Add basic ability to login to an existing numberless account.

app/src/main/java/org/thoughtcrime/securesms/backup/v2/ui/status/ArchiveUploadStatusBannerView.kt

@@ -213,7 +213,7 @@ fun ArchiveUploadStatusBannerView(
         ) {
           DropdownMenus.ItemWithIcon(
             menuController = menuController,
-            drawableResId = R.drawable.symbol_visible_slash,
+            imageVector = SignalIcons.VisibleSlash.imageVector,
             stringResId = R.string.BackupStatus__hide,
             onClick = { emitter(ArchiveUploadStatusBannerViewEvents.HideClicked) }
           )

app/src/main/java/org/thoughtcrime/securesms/registration/v2/AppRegistrationNetworkController.kt

@@ -182,7 +182,8 @@ class AppRegistrationNetworkController(
     aciPreKeys: PreKeyCollection,
     pniPreKeys: PreKeyCollection?,
     fcmToken: String?,
-    skipDeviceTransfer: Boolean
+    skipDeviceTransfer: Boolean,
+    aci: ACI?
   ): RequestResult<RegisterAccountResponse, RegisterAccountError> {
     return registrationApi.registerAccount(
       e164 = e164,
@@ -194,7 +195,8 @@ class AppRegistrationNetworkController(
       aciPreKeys = aciPreKeys,
       pniPreKeys = pniPreKeys,
       fcmToken = fcmToken,
-      skipDeviceTransfer = skipDeviceTransfer
+      skipDeviceTransfer = skipDeviceTransfer,
+      aci = aci
     )
   }
 

core/serialization/src/main/java/org/signal/core/util/serialization/ACISerializer.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.core.util.serialization
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import org.signal.core.models.ServiceId.ACI
+
+class ACISerializer : KSerializer<ACI> {
+  override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("ACI", PrimitiveKind.STRING)
+
+  override fun deserialize(decoder: Decoder): ACI {
+    return ACI.parseOrThrow(decoder.decodeString())
+  }
+
+  override fun serialize(encoder: Encoder, value: ACI) {
+    encoder.encodeString(value.toString())
+  }
+}

core/ui/src/main/java/org/signal/core/ui/compose/SignalIcons.kt

@@ -114,6 +114,8 @@ enum class SignalIcons(private val icon: SignalIcon) : SignalIcon by icon {
   Video(icon(R.drawable.symbol_video_24)),
   ViewOnce(icon(R.drawable.symbol_view_once_24)),
   ViewOnceInfinite(icon(R.drawable.symbol_view_once_infinite_24)),
+  Visible(icon(R.drawable.symbol_visible_24)),
+  VisibleSlash(icon(R.drawable.symbol_visible_slash_24)),
   X(icon(R.drawable.symbol_x_24)),
   XCircle(icon(R.drawable.symbol_x_circle_24)),
   XCircleFill(icon(R.drawable.symbol_x_circle_fill_24))

demo/registration/src/main/java/org/signal/registration/sample/debug/DebugNetworkController.kt

@@ -139,13 +139,14 @@ class DebugNetworkController(
     aciPreKeys: PreKeyCollection,
     pniPreKeys: PreKeyCollection?,
     fcmToken: String?,
-    skipDeviceTransfer: Boolean
+    skipDeviceTransfer: Boolean,
+    aci: ACI?
   ): RequestResult<RegisterAccountResponse, RegisterAccountError> {
     NetworkDebugState.getOverride<RequestResult<RegisterAccountResponse, RegisterAccountError>>("registerAccount")?.let {
       Log.d(TAG, "[registerAccount] Returning debug override")
       return it
     }
-    return delegate.registerAccount(e164, password, sessionId, recoveryPassword, receiptCredentialPresentation, attributes, aciPreKeys, pniPreKeys, fcmToken, skipDeviceTransfer)
+    return delegate.registerAccount(e164, password, sessionId, recoveryPassword, receiptCredentialPresentation, attributes, aciPreKeys, pniPreKeys, fcmToken, skipDeviceTransfer, aci)
   }
 
   override suspend fun createLoginPurchaseReceiptCredential(

demo/registration/src/main/java/org/signal/registration/sample/dependencies/DemoNetworkController.kt

@@ -25,6 +25,7 @@ import okhttp3.Response
 import org.signal.core.models.AccountEntropyPool
 import org.signal.core.models.MasterKey
 import org.signal.core.models.ServiceId
+import org.signal.core.models.ServiceId.ACI
 import org.signal.core.models.backup.MessageBackupKey
 import org.signal.core.util.Base64
 import org.signal.core.util.Hex
@@ -212,7 +213,8 @@ class DemoNetworkController(
     aciPreKeys: PreKeyCollection,
     pniPreKeys: PreKeyCollection?,
     fcmToken: String?,
-    skipDeviceTransfer: Boolean
+    skipDeviceTransfer: Boolean,
+    aci: ACI?
   ): RequestResult<RegisterAccountResponse, RegisterAccountError> {
     return registrationApi.registerAccount(
       e164 = e164,
@@ -224,7 +226,8 @@ class DemoNetworkController(
       aciPreKeys = aciPreKeys,
       pniPreKeys = pniPreKeys,
       fcmToken = fcmToken,
-      skipDeviceTransfer = skipDeviceTransfer
+      skipDeviceTransfer = skipDeviceTransfer,
+      aci = aci
     )
   }
 

feature/registration/src/main/java/org/signal/registration/NetworkController.kt

@@ -100,15 +100,19 @@ interface NetworkController {
    * Must provide exactly one of [sessionId], [recoveryPassword], or [receiptCredentialPresentation].
    *
    * Providing a [receiptCredentialPresentation] (built by [createReceiptCredentialPresentation] from the credential
-   * issued by [createLoginPurchaseReceiptCredential]) registers an account that has no phone number. For that mode,
-   * [e164] and [pniPreKeys] must be null, and [attributes] must have a null `pniRegistrationId` and a null
-   * `discoverableByPhoneNumber`.
+   * issued by [createLoginPurchaseReceiptCredential]) registers a new account that has no phone number, and providing
+   * an [aci] alongside a [recoveryPassword] logs back in to an existing one. For both, [e164] must be null and
+   * [attributes] must have a null `discoverableByPhoneNumber`. Creating a new account also requires a null
+   * [pniPreKeys] and a null `attributes.pniRegistrationId`, while logging back in requires both to be present -- the
+   * service demands PNI key material of any recovery-by-identifier, then ignores it for an account with no phone
+   * number, so throwaway material is fine.
    *
    * `POST /v1/registration`
    *
    * @param e164 The phone number in E.164 format (used as username for basic auth). Null when registering without a
    *   phone number, in which case the implementation generates a placeholder username the service ignores.
    * @param password The password for basic auth
+   * @param aci The ACI of the existing numberless account to log back in to, used as the username for basic auth.
    */
   suspend fun registerAccount(
     e164: String?,
@@ -120,7 +124,8 @@ interface NetworkController {
     aciPreKeys: PreKeyCollection,
     pniPreKeys: PreKeyCollection?,
     fcmToken: String?,
-    skipDeviceTransfer: Boolean
+    skipDeviceTransfer: Boolean,
+    aci: ACI?
   ): RequestResult<RegisterAccountResponse, RegisterAccountError>
 
   /**

feature/registration/src/main/java/org/signal/registration/PersistedFlowState.kt

@@ -30,6 +30,7 @@ data class PersistedFlowState(
   val restoredAepValue: String? = null,
   val restoreMethodToken: String? = null,
   val storageCapable: Boolean = false,
+  val phoneNumberlessAccount: Boolean = false,
   val smsVerificationCodeRequest: VerificationCodeRequest? = null,
   val callVerificationCodeRequest: VerificationCodeRequest? = null
 )
@@ -49,6 +50,7 @@ fun RegistrationFlowState.toPersistedFlowState(): PersistedFlowState {
     restoredAepValue = unverifiedRestoredAep?.value,
     restoreMethodToken = restoreMethodToken,
     storageCapable = storageCapable,
+    phoneNumberlessAccount = isPhoneNumberlessAccount,
     smsVerificationCodeRequest = lastSmsVerificationCodeRequest,
     callVerificationCodeRequest = lastCallVerificationCodeRequest
   )
@@ -80,6 +82,7 @@ fun PersistedFlowState.toRegistrationFlowState(
     unverifiedRestoredAep = restoredAepValue?.let { AccountEntropyPool(it) },
     restoreMethodToken = restoreMethodToken,
     storageCapable = storageCapable,
+    isPhoneNumberlessAccount = phoneNumberlessAccount,
     lastSmsVerificationCodeRequest = smsVerificationCodeRequest,
     lastCallVerificationCodeRequest = callVerificationCodeRequest
   )

feature/registration/src/main/java/org/signal/registration/RegistrationFlowEvent.kt

@@ -75,9 +75,11 @@ sealed interface RegistrationFlowEvent {
    * @param aci The account identifier the server assigned (or re-confirmed) in the registration response.
    * @param storageCapable Whether the server reports that this account already has SVR/PIN data, as returned in the
    * registration response. Used later (e.g. when skipping a restore) to decide between PIN entry and PIN creation.
+   * @param phoneNumberless Whether the registration response came back without a phone number. Such an account has no
+   * PIN, so the screens that would otherwise ask for or create one must be skipped.
    */
-  data class Registered(val aci: ACI, val accountEntropyPool: AccountEntropyPool, val storageCapable: Boolean) : RegistrationFlowEvent {
-    override fun toString(): String = "Registered(aci=${aci.logString()}, accountEntropyPool=${accountEntropyPool.displayValue.censor()}, storageCapable=$storageCapable)"
+  data class Registered(val aci: ACI, val accountEntropyPool: AccountEntropyPool, val storageCapable: Boolean, val phoneNumberless: Boolean) : RegistrationFlowEvent {
+    override fun toString(): String = "Registered(aci=${aci.logString()}, accountEntropyPool=${accountEntropyPool.displayValue.censor()}, storageCapable=$storageCapable, phoneNumberless=$phoneNumberless)"
   }
 
   /** The master key has been restored from SVR. */

feature/registration/src/main/java/org/signal/registration/RegistrationFlowState.kt

@@ -46,6 +46,9 @@ data class RegistrationFlowState(
   /** Whether the server reported that this account already has SVR/PIN data, captured from the registration response. */
   val storageCapable: Boolean = false,
 
+  /** Whether this account has no phone number, captured from the registration response. Such an account has no PIN. */
+  val isPhoneNumberlessAccount: Boolean = false,
+
   /** The master key we restored from SVR. Needed for initial storage service restore, but afterwards we'll generate a new one. */
   val temporaryMasterKey: MasterKey? = null,
 
@@ -77,7 +80,7 @@ data class RegistrationFlowState(
   val isRestoringNavigationState: Boolean = true
 ) : Parcelable {
   override fun toString(): String {
-    return "RegistrationFlowState(backStack=${backStack.joinToString()}, sessionMetadata=$sessionMetadata, sessionE164=$sessionE164, submittedVerificationCode=${submittedVerificationCode?.censor()}, accountEntropyPool=${accountEntropyPool?.displayValue?.censor()}, aci=${aci?.logString()}, storageCapable=$storageCapable, temporaryMasterKey=${temporaryMasterKey?.toString()?.censor()}, preExistingRegistrationData=$preExistingRegistrationData, doNotAttemptRecoveryPassword=$doNotAttemptRecoveryPassword, pendingRestoreOption=$pendingRestoreOption, unverifiedRestoredAep=${unverifiedRestoredAep?.displayValue?.censor()}, restoreMethodToken=${restoreMethodToken?.censor()}, lastSmsVerificationCodeRequest=$lastSmsVerificationCodeRequest, lastCallVerificationCodeRequest=$lastCallVerificationCodeRequest, isRestoringNavigation=$isRestoringNavigationState)"
+    return "RegistrationFlowState(backStack=${backStack.joinToString()}, sessionMetadata=$sessionMetadata, sessionE164=$sessionE164, submittedVerificationCode=${submittedVerificationCode?.censor()}, accountEntropyPool=${accountEntropyPool?.displayValue?.censor()}, aci=${aci?.logString()}, storageCapable=$storageCapable, isPhoneNumberlessAccount=$isPhoneNumberlessAccount, temporaryMasterKey=${temporaryMasterKey?.toString()?.censor()}, preExistingRegistrationData=$preExistingRegistrationData, doNotAttemptRecoveryPassword=$doNotAttemptRecoveryPassword, pendingRestoreOption=$pendingRestoreOption, unverifiedRestoredAep=${unverifiedRestoredAep?.displayValue?.censor()}, restoreMethodToken=${restoreMethodToken?.censor()}, lastSmsVerificationCodeRequest=$lastSmsVerificationCodeRequest, lastCallVerificationCodeRequest=$lastCallVerificationCodeRequest, isRestoringNavigation=$isRestoringNavigationState)"
   }
 }
 

feature/registration/src/main/java/org/signal/registration/RegistrationNavigation.kt

@@ -114,9 +114,9 @@ import org.signal.registration.screens.restoreselection.ArchiveRestoreOption
 import org.signal.registration.screens.restoreselection.ArchiveRestoreSelectionScreen
 import org.signal.registration.screens.restoreselection.ArchiveRestoreSelectionViewModel
 import org.signal.registration.screens.restoreselection.RegisteredState
-import org.signal.registration.screens.signallogin.SignalLoginScreen
-import org.signal.registration.screens.signallogin.SignalLoginScreenActions
-import org.signal.registration.screens.signallogin.SignalLoginViewModel
+import org.signal.registration.screens.signallogincredentials.SignalLoginCredentialEntryScreen
+import org.signal.registration.screens.signallogincredentials.SignalLoginCredentialEntryScreenActions
+import org.signal.registration.screens.signallogincredentials.SignalLoginCredentialEntryViewModel
 import org.signal.registration.screens.signallogindetails.SignalLoginViewDetailsScreenActions
 import org.signal.registration.screens.signallogindetails.SignalLoginViewDetailsViewModel
 import org.signal.registration.screens.signallogininfo.SignalLoginInfoScreen
@@ -180,9 +180,9 @@ sealed interface RegistrationRoute : NavKey, Parcelable {
   @Serializable
   data object SignalLoginViewDetails : RegistrationRoute
 
-  /** Log in with the account key of a Signal Login the user already owns. */
+  /** Logging in with a Signal Login the user already owns: the account ID and the recovery key that pairs with it. */
   @Serializable
-  data object SignalLogin : RegistrationRoute
+  data object SignalLoginCredentialEntry : RegistrationRoute
 
   /** Optional username selection for a phone-numberless account. */
   @Serializable
@@ -268,6 +268,24 @@ sealed interface RegistrationRoute : NavKey, Parcelable {
           registeredState = RegisteredState.RegisteredAndPinKnown
         )
       }
+
+      /**
+       * For an account reclaimed with an [aep] the user typed in, so either restore source can be read straight away
+       * without asking for a PIN.
+       */
+      fun forPostRegisterWithKnownAep(aep: AccountEntropyPool, hasRemoteBackup: Boolean): ArchiveRestoreSelection {
+        return ArchiveRestoreSelection(
+          restoreOptions = buildList {
+            if (hasRemoteBackup) {
+              add(ArchiveRestoreOption.SignalSecureBackup)
+            }
+            add(ArchiveRestoreOption.LocalBackup)
+            add(ArchiveRestoreOption.None)
+          },
+          registeredState = RegisteredState.RegisteredAndPinKnown,
+          aep = aep
+        )
+      }
     }
   }
 
@@ -301,9 +319,15 @@ sealed interface RegistrationRoute : NavKey, Parcelable {
   @Serializable
   data object EnterAepForRemoteBackupPostRegistration : RegistrationRoute
 
+  /**
+   * @param backwardNavigationAllowed Whether the user can reasonably go backwards in the nav graph.
+   */
   @Serializable
   @TypeParceler<AccountEntropyPool, AccountEntropyPoolParceler>
-  data class RemoteRestore(@Serializable(with = AccountEntropyPoolSerializer::class) val aep: AccountEntropyPool) : RegistrationRoute
+  data class RemoteRestore(
+    @Serializable(with = AccountEntropyPoolSerializer::class) val aep: AccountEntropyPool,
+    val backwardNavigationAllowed: Boolean = false
+  ) : RegistrationRoute
 
   @Serializable
   data object QuickRestoreQrScan : RegistrationRoute
@@ -729,10 +753,10 @@ private fun EntryProviderScope<NavKey>.navigationEntries(
     )
   }
 
-  // -- Signal Login Screen
-  entry<RegistrationRoute.SignalLogin> {
-    val viewModel: SignalLoginViewModel = viewModel(
-      factory = SignalLoginViewModel.Factory(
+  // -- Signal Login Credential Entry Screen
+  entry<RegistrationRoute.SignalLoginCredentialEntry> {
+    val viewModel: SignalLoginCredentialEntryViewModel = viewModel(
+      factory = SignalLoginCredentialEntryViewModel.Factory(
         repository = registrationRepository,
         parentEventEmitter = registrationViewModel::onEvent
       )
@@ -741,11 +765,11 @@ private fun EntryProviderScope<NavKey>.navigationEntries(
     val context = LocalContext.current
     CollectActions(viewModel.actions) { action ->
       when (action) {
-        SignalLoginScreenActions.OpenNeedHelpArticle -> openUrl(context, SIGNAL_LOGIN_LEARN_MORE_URL)
+        SignalLoginCredentialEntryScreenActions.OpenNeedHelpArticle -> openUrl(context, SIGNAL_LOGIN_LEARN_MORE_URL)
       }
     }
 
-    SignalLoginScreen(
+    SignalLoginCredentialEntryScreen(
       state = state,
       onEvent = { viewModel.onEvent(it) }
     )
@@ -889,6 +913,7 @@ private fun EntryProviderScope<NavKey>.navigationEntries(
     val viewModel: RemoteBackupRestoreViewModel = viewModel(
       factory = RemoteBackupRestoreViewModel.Factory(
         aep = key.aep,
+        canNavigateBackwards = key.backwardNavigationAllowed,
         repository = registrationRepository,
         parentState = registrationViewModel.state,
         parentEventEmitter = registrationViewModel::onEvent

feature/registration/src/main/java/org/signal/registration/RegistrationRepository.kt

@@ -22,6 +22,7 @@ import kotlinx.coroutines.tasks.await
 import kotlinx.coroutines.withContext
 import kotlinx.coroutines.withTimeoutOrNull
 import kotlinx.serialization.json.Json
+import okio.ByteString
 import okio.ByteString.Companion.toByteString
 import org.signal.archive.LocalBackupRestoreProgress
 import org.signal.core.models.AccountEntropyPool
@@ -355,7 +356,7 @@ class RegistrationRepository(
   }
 
   /**
-   * Registers a new account that has no phone number, redeeming [receiptCredentialPresentation] (issued for a
+   * Registers a brand new account that has no phone number, by redeeming [receiptCredentialPresentation] (issued for a
    * completed Signal Login purchase) as proof of payment.
    *
    * @return The registration result containing account information or an error
@@ -369,7 +370,10 @@ class RegistrationRepository(
       sessionId = null,
       recoveryPassword = null,
       receiptCredentialPresentation = receiptCredentialPresentation,
-      skipDeviceTransfer = skipDeviceTransfer
+      aci = null,
+      registrationLock = null,
+      skipDeviceTransfer = skipDeviceTransfer,
+      existingAccountEntropyPool = null
     )
 
     if (result is RequestResult.Success) {
@@ -384,6 +388,35 @@ class RegistrationRepository(
     result
   }
 
+  /**
+   * Logs back in to the account with no phone number identified by [aci], using the [recoveryPassword] and [aep]
+   * behind it.
+   */
+  suspend fun reRegisterAccountWithoutPhoneNumber(
+    aci: ACI,
+    recoveryPassword: String,
+    aep: AccountEntropyPool,
+    registrationLock: String? = null,
+    skipDeviceTransfer: Boolean = true
+  ): RequestResult<RegisteredAccountData, RegisterAccountError> = withContext(Dispatchers.IO) {
+    val result = registerAccount(
+      e164 = null,
+      sessionId = null,
+      recoveryPassword = recoveryPassword,
+      receiptCredentialPresentation = null,
+      aci = aci,
+      registrationLock = registrationLock,
+      skipDeviceTransfer = skipDeviceTransfer,
+      existingAccountEntropyPool = aep
+    )
+
+    if (result is RequestResult.Success && result.result.response.authCredentialSalt == null) {
+      Log.w(TAG, "[reRegisterAccountWithoutPhoneNumber] The service did not return an authCredentialSalt!")
+    }
+
+    result
+  }
+
   /**
    * Starts a provisioning session for QR-based quick restore.
    * See [NetworkController.startProvisioning].
@@ -653,8 +686,10 @@ class RegistrationRepository(
    * 4. On success, saves the registration data to persistent storage
    *
    * Must provide exactly one of [sessionId], [recoveryPassword], or [receiptCredentialPresentation]. Providing a
-   * [receiptCredentialPresentation] registers an account that has no phone number, so [e164] must be null and no PNI
-   * key material is generated or sent.
+   * [receiptCredentialPresentation] or an [aci] registers an account that has no phone number, so [e164] must be null.
+   * A [receiptCredentialPresentation] sends no PNI key material at all, while an [aci] always sends throwaway PNI key
+   * material, which the service requires of any recovery-by-identifier. That material is only kept locally if the
+   * response says the reclaimed account has a phone number, meaning the service kept it too.
    *
    * @param e164 The phone number in E.164 format (used for basic auth). Null when registering without a phone number.
    * @param sessionId The verified session ID from phone number verification.
@@ -663,6 +698,7 @@ class RegistrationRepository(
    * @param registrationLock The registration lock token derived from the master key (if unlocking a reglocked account). Important: if you provide this, the user will be registered with reglock enabled.
    * @param skipDeviceTransfer Whether to skip device transfer flow
    * @param preExistingRegistrationData If present, we will use the pre-existing key material from this pre-existing registration rather than generating new key material.
+   * @param aci The ACI of the existing phone-numberless account being logged back in to. Requires a [recoveryPassword], and implies there is no [e164].
    * @return The registration result containing account information or an error
    */
   private suspend fun registerAccount(
@@ -670,6 +706,7 @@ class RegistrationRepository(
     sessionId: String?,
     recoveryPassword: String?,
     receiptCredentialPresentation: ReceiptCredentialPresentation? = null,
+    aci: ACI? = null,
     registrationLock: String? = null,
     skipDeviceTransfer: Boolean = true,
     existingAccountEntropyPool: AccountEntropyPool? = null,
@@ -677,16 +714,17 @@ class RegistrationRepository(
     existingPniIdentityKeyPair: IdentityKeyPair? = null,
     unrestrictedUnidentifiedAccess: Boolean = false
   ): RequestResult<RegisteredAccountData, RegisterAccountError> = withContext(Dispatchers.IO) {
-    val phoneNumberless = receiptCredentialPresentation != null
+    val phoneNumberless = receiptCredentialPresentation != null || aci != null
 
     check(listOfNotNull(sessionId, recoveryPassword, receiptCredentialPresentation).size == 1) { "Must provide exactly one of: sessionId, recoveryPassword, receiptCredentialPresentation" }
+    check(aci == null || recoveryPassword != null) { "Must provide a recoveryPassword alongside an aci" }
     if (phoneNumberless) {
       check(e164 == null) { "Must not provide an e164 when registering without a phone number" }
     } else {
       check(e164 != null) { "Must provide an e164 when registering with a phone number" }
     }
 
-    Log.i(TAG, "[registerAccount] Starting registration for $e164. sessionId: ${sessionId != null}, recoveryPassword: ${recoveryPassword != null}, receiptCredentialPresentation: $phoneNumberless, registrationLock: ${registrationLock != null}, skipDeviceTransfer: $skipDeviceTransfer, existingAep: ${existingAccountEntropyPool != null}")
+    Log.i(TAG, "[registerAccount] Starting registration for $e164. sessionId: ${sessionId != null}, recoveryPassword: ${recoveryPassword != null}, receiptCredentialPresentation: ${receiptCredentialPresentation != null}, aci: ${aci != null}, phoneNumberless: $phoneNumberless, registrationLock: ${registrationLock != null}, skipDeviceTransfer: $skipDeviceTransfer, existingAep: ${existingAccountEntropyPool != null}")
 
     val inProgressData = storageController.readInProgressRegistrationData()
     val resumedAciIdentityKeyPair = inProgressData.accountData?.aciIdentityKeyPair?.takeIf { it.size > 0 }?.let { IdentityKeyPair(it.toByteArray()) }
@@ -732,6 +770,16 @@ class RegistrationRepository(
 
     SensitiveLog.d(TAG, "[registerAccount] Using master key [${Hex.toStringCondensed(newMasterKey.serialize())}] and RRP [$newRecoveryPassword]")
 
+    val pniKeyMaterialForRequest = when {
+      // Traditional registration with a number requires PNI material
+      !phoneNumberless -> checkNotNull(keyMaterial.pni) { "Missing PNI key material for a primary registration!" }
+      // Numberless re-registration requires PNI material just in case, and the response tells us if we should keep it
+      aci != null -> generatePniKeyMaterial()
+      // Fresh numberless registration requires null PNI material
+      receiptCredentialPresentation != null -> null
+      else -> error("Invalid state! numberless: $phoneNumberless, hasAci: ${aci != null}, hasReceiptCredential: ${receiptCredentialPresentation != null}")
+    }
+
     val accountAttributes = AccountAttributes(
       signalingKey = null,
       registrationId = keyMaterial.aciRegistrationId,
@@ -743,18 +791,15 @@ class RegistrationRepository(
       unrestrictedUnidentifiedAccess = unrestrictedUnidentifiedAccess,
       discoverableByPhoneNumber = if (phoneNumberless) null else false, // Important -- this should be false initially, and then the user should be given a choice as to whether to turn it on later
       capabilities = getAccountCapabilities().copy(optionalPhoneNumber = phoneNumberless),
-      pniRegistrationId = keyMaterial.pni?.registrationId,
+      pniRegistrationId = pniKeyMaterialForRequest?.registrationId,
       recoveryPassword = newRecoveryPassword
     )
 
-    val pniPreKeys = if (phoneNumberless) {
-      null
-    } else {
-      val pniKeyMaterial = checkNotNull(keyMaterial.pni) { "Missing PNI key material for a primary registration!" }
+    val pniPreKeys = pniKeyMaterialForRequest?.let {
       PreKeyCollection(
-        identityKey = pniKeyMaterial.identityKeyPair.publicKey,
-        signedPreKey = pniKeyMaterial.signedPreKey,
-        lastResortKyberPreKey = pniKeyMaterial.lastResortKyberPreKey
+        identityKey = it.identityKeyPair.publicKey,
+        signedPreKey = it.signedPreKey,
+        lastResortKyberPreKey = it.lastResortKyberPreKey
       )
     }
 
@@ -768,7 +813,8 @@ class RegistrationRepository(
       aciPreKeys = keyMaterial.toAciPreKeyCollection(),
       pniPreKeys = pniPreKeys,
       fcmToken = fcmToken,
-      skipDeviceTransfer = skipDeviceTransfer
+      skipDeviceTransfer = skipDeviceTransfer,
+      aci = aci
     )
 
     when (result) {
@@ -778,6 +824,14 @@ class RegistrationRepository(
           checkNotNull(result.result.pni) { "Missing PNI in the response for a primary registration!" }
         }
 
+        // Numberless re-reg sends throwaway PNI material, and the response tells us if we had a phone number or not.
+        // Only keep the PNI material if it turns out there was a number associated with the account.
+        val pniKeyMaterialToKeep = keyMaterial.pni ?: pniKeyMaterialForRequest?.takeIf { result.result.pni != null }
+
+        if (aci != null) {
+          Log.i(TAG, "[registerAccount] Reclaimed an account that ${if (result.result.pni != null) "has" else "does not have"} a phone number. Keeping the PNI key material we sent: ${pniKeyMaterialToKeep != null}")
+        }
+
         storageController.updateInProgressRegistrationData {
           this.accountEntropyPool = keyMaterial.accountEntropyPool.value
         }
@@ -788,10 +842,24 @@ class RegistrationRepository(
           this.servicePassword = keyMaterial.servicePassword
           this.reRegistration = result.result.reregistration
           this.authCredentialSalt = result.result.authCredentialSalt?.let { Base64.decode(it).toByteString() }
+
+          if (pniKeyMaterialToKeep != null) {
+            this.pniIdentityKeyPair = pniKeyMaterialToKeep.identityKeyPair.serialize().toByteString()
+            this.pniSignedPreKey = pniKeyMaterialToKeep.signedPreKey.serialize().toByteString()
+            this.pniLastResortKyberPreKey = pniKeyMaterialToKeep.lastResortKyberPreKey.serialize().toByteString()
+            this.pniRegistrationId = pniKeyMaterialToKeep.registrationId
+          } else {
+            // An earlier, abandoned attempt in this same registration may have left PNI material behind, and an
+            // account with no PNI must not be committed holding on to it.
+            this.pniIdentityKeyPair = ByteString.EMPTY
+            this.pniSignedPreKey = ByteString.EMPTY
+            this.pniLastResortKyberPreKey = ByteString.EMPTY
+            this.pniRegistrationId = 0
+          }
         }
         storageController.commitRegistrationData()
 
-        RequestResult.Success(RegisteredAccountData(result.result, keyMaterial, ACI.parseOrThrow(result.result.aci)))
+        RequestResult.Success(RegisteredAccountData(result.result, keyMaterial.copy(pni = pniKeyMaterialToKeep), ACI.parseOrThrow(result.result.aci)))
       }
       is RequestResult.NonSuccess -> result
       is RequestResult.RetryableNetworkError -> result
@@ -1133,7 +1201,8 @@ class RegistrationRepository(
 
   /**
    * @param includePniKeyMaterial Whether to generate PNI key material at all. False for an account with no phone number,
-   *   which has no PNI to attach the keys to.
+   *   which has no PNI to attach the keys to. See [generatePniKeyMaterial] for the material such a registration sends
+   *   without keeping.
    */
   private fun generateKeyMaterial(
     existingAccountEntropyPool: AccountEntropyPool? = null,
@@ -1150,18 +1219,7 @@ class RegistrationRepository(
     val aciSignedPreKey = generateSignedPreKey(generatePreKeyId(), timestamp, aciIdentityKeyPair)
     val aciLastResortKyberPreKey = generateKyberPreKey(generatePreKeyId(), timestamp, aciIdentityKeyPair)
 
-    val pniKeyMaterial = if (includePniKeyMaterial) {
-      val pniIdentityKeyPair = existingPniIdentityKeyPair ?: IdentityKeyPair.generate()
-
-      KeyMaterial.PniKeyMaterial(
-        identityKeyPair = pniIdentityKeyPair,
-        signedPreKey = generateSignedPreKey(generatePreKeyId(), timestamp, pniIdentityKeyPair),
-        lastResortKyberPreKey = generateKyberPreKey(generatePreKeyId(), timestamp, pniIdentityKeyPair),
-        registrationId = generateRegistrationId()
-      )
-    } else {
-      null
-    }
+    val pniKeyMaterial = if (includePniKeyMaterial) generatePniKeyMaterial(existingPniIdentityKeyPair) else null
 
     val profileKey = profileKey ?: generateProfileKey()
 
@@ -1178,6 +1236,19 @@ class RegistrationRepository(
     )
   }
 
+  /** A self-consistent set of PNI key material: the pre-keys are signed by the identity key returned alongside them. */
+  private fun generatePniKeyMaterial(existingPniIdentityKeyPair: IdentityKeyPair? = null): KeyMaterial.PniKeyMaterial {
+    val pniIdentityKeyPair = existingPniIdentityKeyPair ?: IdentityKeyPair.generate()
+    val timestamp = System.currentTimeMillis()
+
+    return KeyMaterial.PniKeyMaterial(
+      identityKeyPair = pniIdentityKeyPair,
+      signedPreKey = generateSignedPreKey(generatePreKeyId(), timestamp, pniIdentityKeyPair),
+      lastResortKyberPreKey = generateKyberPreKey(generatePreKeyId(), timestamp, pniIdentityKeyPair),
+      registrationId = generateRegistrationId()
+    )
+  }
+
   private fun generateSignedPreKey(id: Int, timestamp: Long, identityKeyPair: IdentityKeyPair): SignedPreKeyRecord {
     val keyPair = ECKeyPair.generate()
     val signature = identityKeyPair.privateKey.calculateSignature(keyPair.publicKey.serialize())

feature/registration/src/main/java/org/signal/registration/RegistrationViewModel.kt

@@ -106,7 +106,7 @@ class RegistrationViewModel(
         lastSmsVerificationCodeRequest = event.nextSmsAllowedTimestamp?.let { VerificationCodeRequest(event.e164, it) } ?: state.lastSmsVerificationCodeRequest,
         lastCallVerificationCodeRequest = event.nextCallAllowedTimestamp?.let { VerificationCodeRequest(event.e164, it) } ?: state.lastCallVerificationCodeRequest
       )
-      is RegistrationFlowEvent.Registered -> state.copy(aci = event.aci, accountEntropyPool = event.accountEntropyPool, storageCapable = event.storageCapable)
+      is RegistrationFlowEvent.Registered -> state.copy(aci = event.aci, accountEntropyPool = event.accountEntropyPool, storageCapable = event.storageCapable, isPhoneNumberlessAccount = event.phoneNumberless)
       is RegistrationFlowEvent.MasterKeyRestoredFromSvr -> state.copy(temporaryMasterKey = event.masterKey)
       is RegistrationFlowEvent.NavigateToScreen -> applyNavigationToScreenEvent(state, event)
       is RegistrationFlowEvent.NavigateBackToScreen -> applyNavigateBackToScreenEvent(state, event)
@@ -157,8 +157,8 @@ class RegistrationViewModel(
       is RegistrationRoute.Welcome,
       is RegistrationRoute.PinCreate,
       is RegistrationRoute.PinEntryForSvrRestore,
-      is RegistrationRoute.SignalLoginInfo,
-      is RegistrationRoute.RemoteRestore -> true
+      is RegistrationRoute.SignalLoginInfo -> true
+      is RegistrationRoute.RemoteRestore -> !this.backwardNavigationAllowed
       is RegistrationRoute.ArchiveRestoreSelection -> this.registeredState != RegisteredState.NotRegistered
       else -> false
     }

feature/registration/src/main/java/org/signal/registration/screens/aepentry/AepInput.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.aepentry
+
+import org.signal.core.models.AccountEntropyPool
+import org.signal.core.util.censor
+
+/**
+ * Recovery key text as the user has typed it so far, alongside the normalized form and whatever is currently wrong with
+ * it. Every screen that collects a recovery key shares this so they all agree on when a key is too long, malformed, or
+ * finished.
+ *
+ * @param enteredText The typed text, preserved verbatim (illegal characters stripped) so #/= stay visible as they are typed.
+ * @param normalized Storage-normalized lowercase form of [enteredText], used for validation and submit.
+ */
+data class AepInput(
+  val enteredText: String = "",
+  val normalized: String = "",
+  val isValid: Boolean = false,
+  val error: AepValidationError? = null
+) {
+
+  override fun toString(): String = "AepInput(enteredText=${enteredText.censor()}, normalized=${normalized.censor()}, isValid=$isValid, error=$error)"
+
+  companion object {
+    /**
+     * Normalizes [input] and works out what, if anything, is wrong with it. An error the user has already been shown
+     * sticks around until it is actually resolved, so [previousError] gets a say in the outcome.
+     */
+    fun from(input: String, previousError: AepValidationError? = null): AepInput {
+      val enteredText = AccountEntropyPool.removeIllegalCharacters(input).take(AccountEntropyPool.LENGTH + 16)
+      val normalized = AccountEntropyPool.formatForStorage(enteredText).lowercase()
+
+      val isValid = AccountEntropyPool.isFullyValid(normalized)
+      val isShort = normalized.length < AccountEntropyPool.LENGTH
+      val isExact = normalized.length == AccountEntropyPool.LENGTH
+
+      val carriedError = when (previousError) {
+        is AepValidationError.TooLong -> if (isShort || isExact) null else previousError.copy(count = normalized.length)
+        AepValidationError.Invalid -> if (isValid) null else previousError
+        AepValidationError.Incorrect -> null
+        null -> null
+      }
+
+      val error = carriedError ?: when {
+        !isShort && !isExact -> AepValidationError.TooLong(normalized.length, AccountEntropyPool.LENGTH)
+        !isValid && isExact -> AepValidationError.Invalid
+        else -> null
+      }
+
+      return AepInput(enteredText = enteredText, normalized = normalized, isValid = isValid, error = error)
+    }
+  }
+}

feature/registration/src/main/java/org/signal/registration/screens/aepentry/EnterAepForLocalBackupViewModel.kt

@@ -92,15 +92,15 @@ class EnterAepForLocalBackupViewModel(
   }
 
   private suspend fun applySubmit(inputState: EnterAepState, stateEmitter: (EnterAepState) -> Unit) {
-    check(inputState.isBackupKeyValid) { "AEP is not valid, should not have gotten here." }
+    check(inputState.recoveryKey.isValid) { "AEP is not valid, should not have gotten here." }
 
     if (!isPreRegistration) {
-      resultBus.sendResult(resultKey, EnterAepForLocalBackupResult.RestoreReady(inputState.backupKey))
+      resultBus.sendResult(resultKey, EnterAepForLocalBackupResult.RestoreReady(inputState.recoveryKey.normalized))
       parentEventEmitter.navigateBack()
       return
     }
 
-    val aep = AccountEntropyPool(inputState.backupKey)
+    val aep = AccountEntropyPool(inputState.recoveryKey.normalized)
 
     stateEmitter(inputState.copy(isRegistering = true))
 
@@ -108,7 +108,7 @@ class EnterAepForLocalBackupViewModel(
     // only mean the backup belongs to a different account rather than a mistyped key.
     if (!repository.verifyLocalBackupKey(checkNotNull(backupUri).toUri(), aep)) {
       Log.w(TAG, "[Submit] Entered key cannot decrypt the selected backup.")
-      stateEmitter(inputState.copy(isRegistering = false, aepValidationError = AepValidationError.Incorrect))
+      stateEmitter(inputState.copy(isRegistering = false, recoveryKey = inputState.recoveryKey.copy(error = AepValidationError.Incorrect)))
       return
     }
 
@@ -131,8 +131,8 @@ class EnterAepForLocalBackupViewModel(
         val (response, keyMaterial, aci) = result.result
 
         stateEmitter(inputState.copy(isRegistering = false))
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
-        resultBus.sendResult(resultKey, EnterAepForLocalBackupResult.RestoreReady(inputState.backupKey))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
+        resultBus.sendResult(resultKey, EnterAepForLocalBackupResult.RestoreReady(inputState.recoveryKey.normalized))
         parentEventEmitter.navigateBack()
       }
       is RequestResult.NonSuccess -> {

feature/registration/src/main/java/org/signal/registration/screens/aepentry/EnterAepForRemoteBackupPostRegistrationViewModel.kt

@@ -66,9 +66,9 @@ class EnterAepForRemoteBackupPostRegistrationViewModel(
    * failing partway through a restore with no recourse.
    */
   private suspend fun applySubmit(inputState: EnterAepState, stateEmitter: (EnterAepState) -> Unit) {
-    check(inputState.isBackupKeyValid) { "AEP is not valid, should not have gotten here." }
+    check(inputState.recoveryKey.isValid) { "AEP is not valid, should not have gotten here." }
 
-    val aep = AccountEntropyPool(inputState.backupKey)
+    val aep = AccountEntropyPool(inputState.recoveryKey.normalized)
 
     stateEmitter(inputState.copy(isRegistering = true))
 
@@ -83,10 +83,13 @@ class EnterAepForRemoteBackupPostRegistrationViewModel(
       }
       is RequestResult.NonSuccess -> {
         when (val error = result.error) {
-          is NetworkController.VerifyBackupKeyError.IncorrectKey,
+          is NetworkController.VerifyBackupKeyError.IncorrectKey -> {
+            Log.w(TAG, "[Submit] Entered backup key is incorrect.")
+            stateEmitter(inputState.copy(isRegistering = false, recoveryKey = inputState.recoveryKey.copy(error = AepValidationError.Incorrect)))
+          }
           is NetworkController.VerifyBackupKeyError.NoBackup -> {
-            Log.w(TAG, "[Submit] Entered backup key is incorrect (error: $error).")
-            stateEmitter(inputState.copy(isRegistering = false, aepValidationError = AepValidationError.Incorrect))
+            Log.w(TAG, "[Submit] The key verified, but the account has no remote backup.")
+            stateEmitter(inputState.copy(isRegistering = false, registrationError = RegistrationError.NoRemoteBackup))
           }
           is NetworkController.VerifyBackupKeyError.RateLimited -> {
             Log.w(TAG, "[Submit] Rate limited (retryAfter: ${error.retryAfter}).")

feature/registration/src/main/java/org/signal/registration/screens/aepentry/EnterAepForRemoteBackupPreRegistrationViewModel.kt

@@ -71,9 +71,9 @@ class EnterAepForRemoteBackupPreRegistrationViewModel(
   }
 
   private suspend fun applySubmit(inputState: EnterAepState, stateEmitter: (EnterAepState) -> Unit) {
-    check(inputState.isBackupKeyValid) { "AEP is not valid, should not have gotten here." }
+    check(inputState.recoveryKey.isValid) { "AEP is not valid, should not have gotten here." }
 
-    val aep = AccountEntropyPool(inputState.backupKey)
+    val aep = AccountEntropyPool(inputState.recoveryKey.normalized)
 
     stateEmitter(inputState.copy(isRegistering = true))
     parentEventEmitter(RegistrationFlowEvent.UserSuppliedAepSubmitted(aep))
@@ -94,7 +94,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModel(
         val (response, keyMaterial, aci) = result.result
 
         stateEmitter(inputState.copy(isRegistering = false))
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
         parentEventEmitter.navigateTo(RegistrationRoute.RemoteRestore(aep))
       }
       is RequestResult.NonSuccess -> {
@@ -105,7 +105,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModel(
               inputState.copy(
                 isRegistering = false,
                 registrationError = RegistrationError.IncorrectRecoveryPassword,
-                aepValidationError = AepValidationError.Incorrect
+                recoveryKey = inputState.recoveryKey.copy(error = AepValidationError.Incorrect)
               )
             )
           }

feature/registration/src/main/java/org/signal/registration/screens/aepentry/EnterAepScreen.kt

@@ -21,6 +21,7 @@ import androidx.compose.foundation.text.KeyboardActions
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
@@ -36,6 +37,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
+import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
@@ -102,25 +104,29 @@ private fun DifferentAccountDialog(onEvent: (EnterAepEvents) -> Unit) {
 }
 
 /**
- * Shows a dismissable dialog for generic registration errors (network/rate-limit/unknown). Incorrect-key errors are
- * surfaced inline on the text field instead, so they are intentionally not shown here.
+ * Shows a dismissable dialog for registration errors the text field can't express: the generic ones
+ * (network/rate-limit/unknown), plus [RegistrationError.NoRemoteBackup], which gets its own title and body so it does
+ * not read as a rejected key. Incorrect-key errors are surfaced inline on the text field instead.
  */
 @Composable
 private fun RegistrationErrorDialog(error: RegistrationError?, onEvent: (EnterAepEvents) -> Unit) {
-  val message = when (error) {
-    RegistrationError.NetworkError -> stringResource(R.string.VerificationCodeScreen__network_error)
-    RegistrationError.RateLimited -> stringResource(R.string.VerificationCodeScreen__too_many_attempts)
-    RegistrationError.UnknownError -> stringResource(R.string.VerificationCodeScreen__an_unexpected_error_occurred)
-    RegistrationError.IncorrectRecoveryPassword, null -> null
-  } ?: return
+  val (title, message) = when (error) {
+    RegistrationError.NetworkError -> null to stringResource(R.string.VerificationCodeScreen__network_error)
+    RegistrationError.RateLimited -> null to stringResource(R.string.VerificationCodeScreen__too_many_attempts)
+    RegistrationError.UnknownError -> null to stringResource(R.string.VerificationCodeScreen__an_unexpected_error_occurred)
+    RegistrationError.NoRemoteBackup -> stringResource(R.string.EnterAepScreen__no_backup_found) to stringResource(R.string.EnterAepScreen__no_backup_found_body)
+    RegistrationError.IncorrectRecoveryPassword, null -> return
+  }
 
   Dialogs.SimpleMessageDialog(
+    title = title,
     message = message,
     dismiss = stringResource(android.R.string.ok),
     onDismiss = { onEvent(EnterAepEvents.DismissError) }
   )
 }
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 private fun OnePaneLayout(
   params: RegistrationScaffold.Params.OnePane,
@@ -129,6 +135,7 @@ private fun OnePaneLayout(
   modifier: Modifier = Modifier
 ) {
   val scrollState = rememberScrollState()
+  val topBarScrollBehavior = RegistrationScaffold.rememberTopBarScrollBehavior()
 
   OnePaneRegistrationScaffold(
     modifier = modifier
@@ -139,6 +146,7 @@ private fun OnePaneLayout(
       Column(
         modifier = Modifier
           .fillMaxSize()
+          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
           .verticalScroll(scrollState)
           .padding(paddingValues),
         horizontalAlignment = Alignment.CenterHorizontally
@@ -165,7 +173,7 @@ private fun OnePaneLayout(
             modifier = Modifier.weight(1f),
             contentAlignment = Alignment.CenterStart
           ) {
-            NoRecoverKeyButton(onEvent)
+            NoRecoveryKeyButton(onEvent)
           }
           Box(
             modifier = Modifier.weight(1f),
@@ -179,6 +187,7 @@ private fun OnePaneLayout(
   )
 }
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 private fun TwoPaneLayout(
   params: RegistrationScaffold.Params.TwoPane,
@@ -188,6 +197,7 @@ private fun TwoPaneLayout(
 ) {
   val firstPaneScrollState = rememberScrollState()
   val secondPaneScrollState = rememberScrollState()
+  val topBarScrollBehavior = RegistrationScaffold.rememberTopBarScrollBehavior()
 
   TwoPaneRegistrationScaffold(
     modifier = modifier
@@ -229,7 +239,7 @@ private fun TwoPaneLayout(
             .fillMaxWidth()
             .padding(16.dp)
         ) {
-          NoRecoverKeyButton(onEvent)
+          NoRecoveryKeyButton(onEvent)
           Spacer(modifier = Modifier.size(24.dp))
           NextButton(state, onEvent)
         }
@@ -267,7 +277,7 @@ private fun RecoveryKeyTextField(state: EnterAepState, onEvent: (EnterAepEvents)
   val autoFillHelper = passwordAutoFillHelper { onEvent(EnterAepEvents.BackupKeyChanged(it)) }
 
   TextField(
-    value = state.enteredText,
+    value = state.recoveryKey.enteredText,
     onValueChange = {
       onEvent(EnterAepEvents.BackupKeyChanged(it))
       autoFillHelper.onValueChanged(it)
@@ -290,21 +300,21 @@ private fun RecoveryKeyTextField(state: EnterAepState, onEvent: (EnterAepEvents)
     ),
     keyboardActions = KeyboardActions(
       onNext = {
-        if (state.isBackupKeyValid) {
+        if (state.recoveryKey.isValid) {
           keyboardController?.hide()
           onEvent(EnterAepEvents.Submit)
         }
       }
     ),
     supportingText = {
-      when (val error = state.aepValidationError) {
+      when (val error = state.recoveryKey.error) {
         is AepValidationError.TooLong -> Text(stringResource(R.string.EnterAepScreen__too_long, error.count, error.max))
         is AepValidationError.Invalid -> Text(stringResource(R.string.EnterAepScreen__invalid_recovery_key))
         is AepValidationError.Incorrect -> Text(stringResource(R.string.EnterAepScreen__incorrect_recovery_key))
         null -> {}
       }
     },
-    isError = state.aepValidationError != null,
+    isError = state.recoveryKey.error != null,
     minLines = 4,
     visualTransformation = visualTransform,
     modifier = Modifier
@@ -342,7 +352,7 @@ private fun FillFromPasswordManagerButton(onEvent: (EnterAepEvents) -> Unit, mod
 }
 
 @Composable
-private fun NoRecoverKeyButton(onEvent: (EnterAepEvents) -> Unit, modifier: Modifier = Modifier) {
+private fun NoRecoveryKeyButton(onEvent: (EnterAepEvents) -> Unit, modifier: Modifier = Modifier) {
   TextButton(
     modifier = modifier.testTag(TestTags.ENTER_AEP_NO_KEY_BUTTON),
     shape = RoundedCornerShape(0.dp),
@@ -356,7 +366,7 @@ private fun NoRecoverKeyButton(onEvent: (EnterAepEvents) -> Unit, modifier: Modi
 private fun NextButton(state: EnterAepState, onEvent: (EnterAepEvents) -> Unit, modifier: Modifier = Modifier) {
   Buttons.LargeTonal(
     modifier = modifier.testTag(TestTags.ENTER_AEP_NEXT_BUTTON),
-    enabled = state.isBackupKeyValid && state.aepValidationError == null && !state.isRegistering,
+    enabled = state.recoveryKey.isValid && state.recoveryKey.error == null && !state.isRegistering,
     onClick = { onEvent(EnterAepEvents.Submit) }
   ) {
     if (state.isRegistering) {
@@ -426,9 +436,7 @@ private fun EnterAepScreenFilledPreview() {
   Previews.Preview {
     EnterAepScreen(
       state = EnterAepState(
-        enteredText = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
-        backupKey = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
-        isBackupKeyValid = true,
+        recoveryKey = AepInput.from("uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"),
         isPasswordManagerAvailable = true
       ),
       onEvent = {}
@@ -442,9 +450,7 @@ private fun EnterAepScreenLoadingPreview() {
   Previews.Preview {
     EnterAepScreen(
       state = EnterAepState(
-        enteredText = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
-        backupKey = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
-        isBackupKeyValid = true,
+        recoveryKey = AepInput.from("uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"),
         isRegistering = true,
         isPasswordManagerAvailable = true
       ),
@@ -459,10 +465,12 @@ private fun EnterAepScreenErrorPreview() {
   Previews.Preview {
     EnterAepScreen(
       state = EnterAepState(
-        enteredText = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
-        backupKey = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
-        isBackupKeyValid = false,
-        aepValidationError = AepValidationError.Invalid,
+        recoveryKey = AepInput(
+          enteredText = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
+          normalized = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t",
+          isValid = false,
+          error = AepValidationError.Invalid
+        ),
         isPasswordManagerAvailable = true
       ),
       onEvent = {}

feature/registration/src/main/java/org/signal/registration/screens/aepentry/EnterAepScreenEventHandler.kt

@@ -5,49 +5,13 @@
 
 package org.signal.registration.screens.aepentry
 
-import org.signal.core.models.AccountEntropyPool
-
 object EnterAepScreenEventHandler {
 
   fun applyEvent(state: EnterAepState, event: EnterAepEvents): EnterAepState {
     return when (event) {
-      is EnterAepEvents.BackupKeyChanged -> applyBackupKeyChanged(state, event.value)
+      is EnterAepEvents.BackupKeyChanged -> state.copy(recoveryKey = AepInput.from(event.value, state.recoveryKey.error))
       is EnterAepEvents.DismissError -> state.copy(registrationError = null)
       else -> throw UnsupportedOperationException("This event is not handled generically!")
     }
   }
-
-  private fun applyBackupKeyChanged(state: EnterAepState, key: String): EnterAepState {
-    val enteredText = AccountEntropyPool.removeIllegalCharacters(key)
-      .take(AccountEntropyPool.LENGTH + 16)
-    val newKey = AccountEntropyPool.formatForStorage(enteredText).lowercase()
-
-    val isValid = AccountEntropyPool.isFullyValid(newKey)
-    val isShort = newKey.length < AccountEntropyPool.LENGTH
-    val isExact = newKey.length == AccountEntropyPool.LENGTH
-
-    val previousError = state.aepValidationError
-
-    var updatedError: AepValidationError? = when (previousError) {
-      is AepValidationError.TooLong -> if (isShort || isExact) null else previousError.copy(count = newKey.length)
-      AepValidationError.Invalid -> if (isValid) null else previousError
-      AepValidationError.Incorrect -> null
-      null -> null
-    }
-
-    if (updatedError == null) {
-      updatedError = when {
-        !isShort && !isExact -> AepValidationError.TooLong(newKey.length, AccountEntropyPool.LENGTH)
-        !isValid && isExact -> AepValidationError.Invalid
-        else -> null
-      }
-    }
-
-    return state.copy(
-      enteredText = enteredText,
-      backupKey = newKey,
-      isBackupKeyValid = isValid,
-      aepValidationError = updatedError
-    )
-  }
 }

feature/registration/src/main/java/org/signal/registration/screens/aepentry/EnterAepState.kt

@@ -5,15 +5,8 @@
 
 package org.signal.registration.screens.aepentry
 
-import org.signal.core.util.censor
-
 data class EnterAepState(
-  /** The user's typed text, preserved verbatim (illegal chars stripped). Bound to the TextField so #/= stay visible as the user types them. */
-  val enteredText: String = "",
-  /** Storage-normalized lowercase form of [enteredText], used for validation and submit. */
-  val backupKey: String = "",
-  val isBackupKeyValid: Boolean = false,
-  val aepValidationError: AepValidationError? = null,
+  val recoveryKey: AepInput = AepInput(),
   val chunkLength: Int = 4,
   val isRegistering: Boolean = false,
   val registrationError: RegistrationError? = null,
@@ -22,7 +15,7 @@ data class EnterAepState(
   /** Whether a password manager / credential provider is available to fill the recovery key. */
   val isPasswordManagerAvailable: Boolean = false
 ) {
-  override fun toString(): String = "EnterAepState(enteredText=${enteredText.censor()}, backupKey=${backupKey.censor()}, isBackupKeyValid=$isBackupKeyValid, aepValidationError=$aepValidationError, chunkLength=$chunkLength, isRegistering=$isRegistering, registrationError=$registrationError, showDifferentAccountDialog=$showDifferentAccountDialog, isPasswordManagerAvailable=$isPasswordManagerAvailable)"
+  override fun toString(): String = "EnterAepState(recoveryKey=$recoveryKey, chunkLength=$chunkLength, isRegistering=$isRegistering, registrationError=$registrationError, showDifferentAccountDialog=$showDifferentAccountDialog, isPasswordManagerAvailable=$isPasswordManagerAvailable)"
 }
 
 sealed interface AepValidationError {
@@ -33,6 +26,9 @@ sealed interface AepValidationError {
 
 sealed interface RegistrationError {
   data object IncorrectRecoveryPassword : RegistrationError
+
+  /** The key verified against the account, but there is no remote backup to restore. Distinct from an incorrect key. */
+  data object NoRemoteBackup : RegistrationError
   data object RateLimited : RegistrationError
   data object NetworkError : RegistrationError
   data object UnknownError : RegistrationError

feature/registration/src/main/java/org/signal/registration/screens/localbackuprestore/LocalBackupRestoreViewModel.kt

@@ -11,8 +11,8 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
@@ -35,7 +35,7 @@ import kotlin.time.Duration.Companion.seconds
 
 class LocalBackupRestoreViewModel(
   private val repository: RegistrationRepository,
-  parentState: Flow<RegistrationFlowState>,
+  private val parentState: StateFlow<RegistrationFlowState>,
   private val parentEventEmitter: (RegistrationFlowEvent) -> Unit,
   private val isPreRegistration: Boolean,
   private val resultBus: ResultEventBus,
@@ -166,7 +166,11 @@ class LocalBackupRestoreViewModel(
 
       repository.setRestoreDecision(RestoreDecision.COMPLETED)
 
-      if (progress.restoredSvrPin != null) {
+      if (parentState.value.isPhoneNumberlessAccount) {
+        Log.i(TAG, "[onRestoreComplete] Account has no phone number, and therefore no PIN. Completing registration.")
+        repository.restoreAccountRecord()
+        parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
+      } else if (progress.restoredSvrPin != null) {
         repository.restoreAccountRecord()
         parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
       } else if (state.storageCapable) {
@@ -266,7 +270,7 @@ class LocalBackupRestoreViewModel(
 
   class Factory(
     private val repository: RegistrationRepository,
-    private val parentState: Flow<RegistrationFlowState>,
+    private val parentState: StateFlow<RegistrationFlowState>,
     private val parentEventEmitter: (RegistrationFlowEvent) -> Unit,
     private val isPreRegistration: Boolean,
     private val knownAep: AccountEntropyPool?,

feature/registration/src/main/java/org/signal/registration/screens/phonenumber/PhoneNumberEntryViewModel.kt

@@ -312,7 +312,7 @@ class PhoneNumberEntryViewModel(
           Log.i(TAG, "[Register] Successfully re-registered using RRP from pre-existing data.")
           val (response, keyMaterial, aci) = registerResult.result
 
-          parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+          parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
 
           if (response.storageCapable) {
             parentEventEmitter.navigateTo(RegistrationRoute.PinEntryForSvrRestore)
@@ -417,7 +417,7 @@ class PhoneNumberEntryViewModel(
         Log.i(TAG, "[LocalRestore] Successfully registered using RRP from restored AEP.")
         val (response, keyMaterial, aci) = result.result
 
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
 
         if (response.storageCapable) {
           parentEventEmitter.navigateTo(RegistrationRoute.PinEntryForSvrRestore)

feature/registration/src/main/java/org/signal/registration/screens/pinentry/PinEntryForRegistrationLockViewModel.kt

@@ -174,17 +174,22 @@ class PinEntryForRegistrationLockViewModel(
       is RequestResult.Success -> {
         Log.i(TAG, "[PinEntered] Successfully registered!")
         val (response, keyMaterial, aci) = registerResult.result
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
         repository.enqueueSvrResetGuessCountJob()
-        repository.restoreAccountRecord()
         val pendingRestore = pendingRestoreNavigation()
         when {
           pendingRestore != null -> {
             Log.i(TAG, "[PinEntered] A restore was pending behind the registration lock. Resuming it now.")
+            repository.restoreAccountRecord()
             parentEventEmitter.navigateTo(pendingRestore)
           }
-          response.reregistration && parentState.value.pendingRestoreOption == null && parentState.value.preExistingRegistrationData == null -> parentEventEmitter.navigateTo(RegistrationRoute.ArchiveRestoreSelection.forPostRegisterWithPinKnown())
-          else -> parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
+          response.reregistration && parentState.value.pendingRestoreOption == null && parentState.value.preExistingRegistrationData == null -> {
+            parentEventEmitter.navigateTo(RegistrationRoute.ArchiveRestoreSelection.forPostRegisterWithPinKnown())
+          }
+          else -> {
+            repository.restoreAccountRecord()
+            parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
+          }
         }
         state
       }

feature/registration/src/main/java/org/signal/registration/screens/quickrestore/QuickRestoreQrViewModel.kt

@@ -122,7 +122,7 @@ class QuickRestoreQrViewModel(
       is RequestResult.Success -> {
         val (response, keyMaterial, aci) = registerResult.result
         Log.i(TAG, "[Register] Success! reregistration: ${response.reregistration}")
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
         parentEventEmitter.navigateTo(
           RegistrationRoute.ArchiveRestoreSelection.forQuickRestore(
             aep = AccountEntropyPool(message.accountEntropyPool),

feature/registration/src/main/java/org/signal/registration/screens/remotebackuprestore/RemoteBackupRestoreScreen.kt

@@ -6,6 +6,7 @@
 package org.signal.registration.screens.remotebackuprestore
 
 import android.text.format.DateFormat
+import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -20,6 +21,7 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
@@ -62,6 +64,8 @@ fun RemoteRestoreScreen(
     KeepScreenOnEffect()
   }
 
+  BackHandler(enabled = state.restoreState == RemoteBackupRestoreState.RestoreState.InProgress) {}
+
   when (state.loadState) {
     RemoteBackupRestoreState.LoadState.Loading -> {
       Dialogs.IndeterminateProgressDialog(
@@ -134,8 +138,8 @@ private fun OnePaneLayout(
             .fillMaxWidth()
             .padding(24.dp)
         ) {
-          RestoreButton(onEvent, Modifier.fillMaxWidth())
-          CancelButton(onEvent, Modifier.fillMaxWidth())
+          RestoreButton(state, onEvent, Modifier.fillMaxWidth())
+          CancelButton(state, onEvent, Modifier.fillMaxWidth())
         }
       }
     }
@@ -191,9 +195,9 @@ private fun TwoPaneLayout(
             .padding(24.dp),
           horizontalArrangement = Arrangement.End
         ) {
-          CancelButton(onEvent, Modifier)
+          CancelButton(state, onEvent, Modifier)
           Spacer(modifier = Modifier.size(8.dp))
-          RestoreButton(onEvent, Modifier)
+          RestoreButton(state, onEvent, Modifier)
         }
       }
     }
@@ -271,10 +275,12 @@ private fun BackupInfoDetails(state: RemoteBackupRestoreState, modifier: Modifie
 
 @Composable
 private fun RestoreButton(
+  state: RemoteBackupRestoreState,
   onEvent: (RemoteBackupRestoreScreenEvents) -> Unit,
   modifier: Modifier
 ) {
   Buttons.LargeTonal(
+    enabled = !state.isSkipping,
     onClick = { onEvent(RemoteBackupRestoreScreenEvents.BackupRestoreBackup) },
     modifier = modifier.testTag(TestTags.REMOTE_BACKUP_RESTORE_RESTORE_BUTTON)
   ) {
@@ -284,14 +290,24 @@ private fun RestoreButton(
 
 @Composable
 private fun CancelButton(
+  state: RemoteBackupRestoreState,
   onEvent: (RemoteBackupRestoreScreenEvents) -> Unit,
   modifier: Modifier
 ) {
   TextButton(
+    enabled = !state.isSkipping,
     onClick = { onEvent(RemoteBackupRestoreScreenEvents.Cancel) },
     modifier = modifier.testTag(TestTags.REMOTE_BACKUP_RESTORE_CANCEL_BUTTON)
   ) {
-    Text(text = stringResource(android.R.string.cancel))
+    if (state.isSkipping) {
+      CircularProgressIndicator(
+        modifier = Modifier.size(20.dp),
+        strokeWidth = 3.dp,
+        color = MaterialTheme.colorScheme.primary
+      )
+    } else {
+      Text(text = stringResource(android.R.string.cancel))
+    }
   }
 }
 

feature/registration/src/main/java/org/signal/registration/screens/remotebackuprestore/RemoteBackupRestoreState.kt

@@ -17,10 +17,11 @@ data class RemoteBackupRestoreState(
   val restoreState: RestoreState = RestoreState.None,
   val restoreProgress: RestoreProgress? = null,
   val loadAttempts: Int = 0,
-  val showContactSupportDialog: Boolean = false
+  val showContactSupportDialog: Boolean = false,
+  val isSkipping: Boolean = false
 ) {
 
-  override fun toString(): String = "RemoteBackupRestoreState(aep=${aep.displayValue.censor()}, loadState=$loadState, backupTime=$backupTime, backupSize=$backupSize, restoreState=$restoreState, restoreProgress=$restoreProgress, loadAttempts=$loadAttempts, showContactSupportDialog=$showContactSupportDialog)"
+  override fun toString(): String = "RemoteBackupRestoreState(aep=${aep.displayValue.censor()}, loadState=$loadState, backupTime=$backupTime, backupSize=$backupSize, restoreState=$restoreState, restoreProgress=$restoreProgress, loadAttempts=$loadAttempts, showContactSupportDialog=$showContactSupportDialog, isSkipping=$isSkipping)"
 
   enum class LoadState {
     Loading,

feature/registration/src/main/java/org/signal/registration/screens/remotebackuprestore/RemoteBackupRestoreViewModel.kt

@@ -36,6 +36,7 @@ import kotlin.time.Duration.Companion.seconds
 
 class RemoteBackupRestoreViewModel(
   private val aep: AccountEntropyPool,
+  private val canNavigateBackwards: Boolean,
   private val repository: RegistrationRepository,
   private val parentState: StateFlow<RegistrationFlowState>,
   private val parentEventEmitter: (RegistrationFlowEvent) -> Unit,
@@ -76,8 +77,21 @@ class RemoteBackupRestoreViewModel(
         stateEmitter(state)
       }
       is RemoteBackupRestoreScreenEvents.Cancel -> {
-        parentEventEmitter.navigateBack()
-        stateEmitter(state)
+        if (state.isSkipping) {
+          Log.i(TAG, "[Cancel] Already moving on without a remote restore. Ignoring.")
+          return
+        }
+
+        if (canNavigateBackwards) {
+          Log.i(TAG, "[Cancel] Going back to previous screen.")
+          parentEventEmitter.navigateBack()
+          return
+        }
+
+        Log.i(TAG, "[Cancel] Moving on without a remote restore.")
+        stateEmitter(state.copy(isSkipping = true))
+        repository.setRestoreDecision(RestoreDecision.SKIPPED)
+        continuePastRestore()
       }
       is RemoteBackupRestoreScreenEvents.DismissError -> {
         stateEmitter(state.copy(restoreState = RemoteBackupRestoreState.RestoreState.None, restoreProgress = null))
@@ -91,6 +105,28 @@ class RemoteBackupRestoreViewModel(
     }
   }
 
+  private suspend fun continuePastRestore() {
+    when {
+      parentState.value.isPhoneNumberlessAccount -> {
+        Log.i(TAG, "[continuePastRestore] Account has no phone number, and therefore no PIN. Completing registration.")
+        repository.restoreAccountRecord()
+        parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
+      }
+      repository.hasKnownPin() -> {
+        repository.restoreAccountRecord()
+        parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
+      }
+      parentState.value.storageCapable -> {
+        Log.i(TAG, "[continuePastRestore] No PIN is known and the account is storage capable. Navigating to PIN entry to restore the existing PIN.")
+        parentEventEmitter.navigateTo(RegistrationRoute.PinEntryForSvrRestore)
+      }
+      else -> {
+        Log.i(TAG, "[continuePastRestore] No PIN is known and the account is not storage capable. Navigating to PIN creation.")
+        parentEventEmitter.navigateTo(RegistrationRoute.PinCreate)
+      }
+    }
+  }
+
   private fun restoreBackup() {
     viewModelScope.launch {
       repository.restoreRemoteBackup(_state.value.aep).collect { progress ->
@@ -136,21 +172,7 @@ class RemoteBackupRestoreViewModel(
             )
             repository.persistRestoredBackupState(progress.restoredSvrPin, progress.restoredProfileKey)
             repository.setRestoreDecision(RestoreDecision.COMPLETED)
-
-            when {
-              repository.hasKnownPin() -> {
-                repository.restoreAccountRecord()
-                parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
-              }
-              parentState.value.storageCapable -> {
-                Log.i(TAG, "[restoreBackup] No PIN is known and the account is storage capable. Navigating to PIN entry to restore the existing PIN.")
-                parentEventEmitter.navigateTo(RegistrationRoute.PinEntryForSvrRestore)
-              }
-              else -> {
-                Log.i(TAG, "[restoreBackup] No PIN is known and the account is not storage capable. Navigating to PIN creation.")
-                parentEventEmitter.navigateTo(RegistrationRoute.PinCreate)
-              }
-            }
+            continuePastRestore()
           }
           is RemoteBackupRestoreProgress.NetworkError -> {
             Log.w(TAG, "[restoreBackup] Remote restore failed with network error.", progress.cause)
@@ -267,12 +289,13 @@ class RemoteBackupRestoreViewModel(
 
   class Factory(
     private val aep: AccountEntropyPool,
+    private val canNavigateBackwards: Boolean,
     private val repository: RegistrationRepository,
     private val parentState: StateFlow<RegistrationFlowState>,
     private val parentEventEmitter: (RegistrationFlowEvent) -> Unit
   ) : ViewModelProvider.Factory {
     override fun <T : ViewModel> create(modelClass: Class<T>): T {
-      return RemoteBackupRestoreViewModel(aep, repository, parentState, parentEventEmitter) as T
+      return RemoteBackupRestoreViewModel(aep, canNavigateBackwards, repository, parentState, parentEventEmitter) as T
     }
   }
 }

feature/registration/src/main/java/org/signal/registration/screens/restoreselection/ArchiveRestoreSelectionScreen.kt

@@ -5,6 +5,7 @@
 
 package org.signal.registration.screens.restoreselection
 
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -18,6 +19,7 @@ import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
@@ -160,6 +162,8 @@ private fun RestoreOptions(state: ArchiveRestoreSelectionState, onEvent: (Archiv
     }
     RestoreOptionCard(
       option = option,
+      enabled = !state.isSkipping,
+      showSpinner = state.isSkipping && option == ArchiveRestoreOption.None,
       onClick = { onEvent(ArchiveRestoreSelectionScreenEvents.RestoreOptionSelected(option)) }
     )
   }
@@ -168,6 +172,8 @@ private fun RestoreOptions(state: ArchiveRestoreSelectionState, onEvent: (Archiv
 @Composable
 private fun RestoreOptionCard(
   option: ArchiveRestoreOption,
+  enabled: Boolean,
+  showSpinner: Boolean,
   onClick: () -> Unit,
   modifier: Modifier = Modifier
 ) {
@@ -177,6 +183,7 @@ private fun RestoreOptionCard(
         imageVector = SignalIcons.SignalBackupsDisplay.imageVector,
         title = stringResource(R.string.ArchiveRestoreSelectionScreen__from_signal_backups),
         subtitle = stringResource(R.string.ArchiveRestoreSelectionScreen__your_free_or_paid_signal_backup_plan),
+        enabled = enabled,
         onClick = onClick,
         modifier = modifier.testTag(TestTags.ARCHIVE_RESTORE_SELECTION_FROM_SIGNAL_BACKUPS)
       )
@@ -187,6 +194,7 @@ private fun RestoreOptionCard(
         imageVector = SignalIcons.TransferDisplay.imageVector,
         title = stringResource(R.string.ArchiveRestoreSelectionScreen__from_your_old_phone),
         subtitle = stringResource(R.string.ArchiveRestoreSelectionScreen__transfer_directly_from_old),
+        enabled = enabled,
         onClick = onClick,
         modifier = modifier.testTag(TestTags.ARCHIVE_RESTORE_SELECTION_DEVICE_TRANSFER)
       )
@@ -197,6 +205,7 @@ private fun RestoreOptionCard(
         imageVector = SignalIcons.FolderDisplay.imageVector,
         title = stringResource(R.string.ArchiveRestoreSelectionScreen__local_backup_card_title),
         subtitle = stringResource(R.string.ArchiveRestoreSelectionScreen__local_backup_card_description),
+        enabled = enabled,
         onClick = onClick,
         modifier = modifier.testTag(TestTags.ARCHIVE_RESTORE_SELECTION_FROM_BACKUP_FOLDER)
       )
@@ -207,6 +216,8 @@ private fun RestoreOptionCard(
         imageVector = SignalIcons.MobileNextDisplay.imageVector,
         title = stringResource(R.string.ArchiveRestoreSelectionScreen__skip_restore_title),
         subtitle = stringResource(R.string.ArchiveRestoreSelectionScreen__skip_restore_description),
+        enabled = enabled,
+        showSpinner = showSpinner,
         onClick = onClick,
         modifier = modifier.testTag(TestTags.ARCHIVE_RESTORE_SELECTION_NONE)
       )
@@ -220,10 +231,13 @@ private fun SelectionCard(
   title: String,
   subtitle: String,
   onClick: () -> Unit,
+  enabled: Boolean = true,
+  showSpinner: Boolean = false,
   modifier: Modifier = Modifier
 ) {
   Card(
     onClick = onClick,
+    enabled = enabled,
     colors = CardDefaults.cardColors(
       containerColor = MaterialTheme.colorScheme.surfaceContainerLow
     ),
@@ -233,7 +247,17 @@ private fun SelectionCard(
       verticalAlignment = Alignment.CenterVertically,
       modifier = Modifier.padding(16.dp)
     ) {
-      Icon(imageVector = imageVector, contentDescription = null, tint = MaterialTheme.colorScheme.primary, modifier = Modifier.size(48.dp))
+      if (showSpinner) {
+        Box(contentAlignment = Alignment.Center, modifier = Modifier.size(48.dp)) {
+          CircularProgressIndicator(
+            modifier = Modifier.size(24.dp),
+            strokeWidth = 3.dp,
+            color = MaterialTheme.colorScheme.primary
+          )
+        }
+      } else {
+        Icon(imageVector = imageVector, contentDescription = null, tint = MaterialTheme.colorScheme.primary, modifier = Modifier.size(48.dp))
+      }
 
       Spacer(modifier = Modifier.width(16.dp))
 

feature/registration/src/main/java/org/signal/registration/screens/restoreselection/ArchiveRestoreSelectionState.kt

@@ -13,7 +13,9 @@ data class ArchiveRestoreSelectionState(
   /** Token that, if present, indicates that the user did a quick restore, and we should hit a network endpoint to indicate our restore selection.  */
   val restoreMethodToken: String? = null,
   /** Whether the account already has SVR/PIN data on the server. Determines whether skipping restore leads to PIN entry or PIN creation. */
-  val storageCapable: Boolean = false
+  val storageCapable: Boolean = false,
+  /** Whether the skip is underway. The last of the work it does is a network call, so the skip card shows a spinner until the flow moves on. */
+  val isSkipping: Boolean = false
 ) {
-  override fun toString(): String = "ArchiveRestoreSelectionState(restoreOptions=$restoreOptions, showSkipWarningDialog=$showSkipWarningDialog, restoreMethodToken=${restoreMethodToken?.censor()}, storageCapable=$storageCapable)"
+  override fun toString(): String = "ArchiveRestoreSelectionState(restoreOptions=$restoreOptions, showSkipWarningDialog=$showSkipWarningDialog, restoreMethodToken=${restoreMethodToken?.censor()}, storageCapable=$storageCapable, isSkipping=$isSkipping)"
 }

feature/registration/src/main/java/org/signal/registration/screens/restoreselection/ArchiveRestoreSelectionViewModel.kt

@@ -87,7 +87,7 @@ class ArchiveRestoreSelectionViewModel(
                 parentEventEmitter.navigateTo(RegistrationRoute.PhoneNumberEntry)
               }
               knownAep != null -> {
-                parentEventEmitter.navigateTo(RegistrationRoute.RemoteRestore(knownAep))
+                parentEventEmitter.navigateTo(RegistrationRoute.RemoteRestore(knownAep, backwardNavigationAllowed = true))
               }
               else -> {
                 parentEventEmitter.navigateTo(RegistrationRoute.EnterAepForRemoteBackupPostRegistration)
@@ -137,10 +137,14 @@ class ArchiveRestoreSelectionViewModel(
             state.copy(showSkipWarningDialog = false)
           }
           RegisteredState.RegisteredAndPinKnown -> {
+            val skipping = state.copy(showSkipWarningDialog = false, isSkipping = true)
+            stateEmitter(skipping)
+
             notifyOldDevice(state.restoreMethodToken, RestoreMethod.DECLINE)
             repository.setRestoreDecision(RestoreDecision.SKIPPED)
+            repository.restoreAccountRecord()
             parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
-            state.copy(showSkipWarningDialog = false)
+            skipping
           }
         }
       }

feature/registration/src/main/java/org/signal/registration/screens/signallogin/SignalLoginScreen.kt

@@ -1,421 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-import androidx.compose.foundation.Image
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxHeight
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.rememberScrollState
-import androidx.compose.foundation.shape.RoundedCornerShape
-import androidx.compose.foundation.text.KeyboardActions
-import androidx.compose.foundation.text.KeyboardOptions
-import androidx.compose.foundation.verticalScroll
-import androidx.compose.material3.CircularProgressIndicator
-import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Surface
-import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
-import androidx.compose.material3.TextField
-import androidx.compose.material3.TextFieldDefaults
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.focus.FocusRequester
-import androidx.compose.ui.focus.focusRequester
-import androidx.compose.ui.input.nestedscroll.nestedScroll
-import androidx.compose.ui.layout.onGloballyPositioned
-import androidx.compose.ui.platform.LocalSoftwareKeyboardController
-import androidx.compose.ui.platform.testTag
-import androidx.compose.ui.res.painterResource
-import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.text.AnnotatedString
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.text.input.ImeAction
-import androidx.compose.ui.text.input.KeyboardCapitalization
-import androidx.compose.ui.text.input.KeyboardType
-import androidx.compose.ui.text.input.OffsetMapping
-import androidx.compose.ui.text.input.TransformedText
-import androidx.compose.ui.text.input.VisualTransformation
-import androidx.compose.ui.text.style.TextAlign
-import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
-import org.signal.core.ui.compose.AllDevicePreviews
-import org.signal.core.ui.compose.Buttons
-import org.signal.core.ui.compose.Dialogs
-import org.signal.core.ui.compose.Previews
-import org.signal.registration.R
-import org.signal.registration.fonts.MonoTypeface
-import org.signal.registration.screens.OnePaneRegistrationScaffold
-import org.signal.registration.screens.RegistrationScaffold
-import org.signal.registration.screens.TwoPaneRegistrationScaffold
-import org.signal.registration.screens.attachDebugLogHelper
-import org.signal.registration.screens.shared.BackTopAppBar
-import org.signal.registration.test.TestTags
-
-/**
- * Logs an existing Signal Login in by asking for its account key.
- */
-@Composable
-fun SignalLoginScreen(
-  state: SignalLoginState,
-  onEvent: (SignalLoginScreenEvents) -> Unit,
-  modifier: Modifier = Modifier
-) {
-  val simpleError: Pair<String, SignalLoginScreenEvents>? = when {
-    state.dialogs.networkError -> stringResource(R.string.VerificationCodeScreen__network_error) to SignalLoginScreenEvents.NetworkErrorDialogDismissed
-    state.dialogs.unknownError -> stringResource(R.string.VerificationCodeScreen__an_unexpected_error_occurred) to SignalLoginScreenEvents.UnknownErrorDialogDismissed
-    else -> null
-  }
-
-  simpleError?.let { (message, dismissedEvent) ->
-    Dialogs.SimpleMessageDialog(
-      message = message,
-      dismiss = stringResource(android.R.string.ok),
-      onDismiss = { onEvent(dismissedEvent) }
-    )
-  }
-
-  Surface(
-    modifier = modifier
-      .fillMaxSize()
-      .testTag(TestTags.SIGNAL_LOGIN_SCREEN)
-  ) {
-    when (val params = RegistrationScaffold.rememberLayoutParams()) {
-      is RegistrationScaffold.Params.OnePane -> OnePaneLayout(params, state, onEvent)
-      is RegistrationScaffold.Params.TwoPane -> TwoPaneLayout(params, state, onEvent)
-    }
-  }
-}
-
-@OptIn(ExperimentalMaterial3Api::class)
-@Composable
-private fun OnePaneLayout(
-  params: RegistrationScaffold.Params.OnePane,
-  state: SignalLoginState,
-  onEvent: (SignalLoginScreenEvents) -> Unit
-) {
-  val scrollState = rememberScrollState()
-  val topBarScrollBehavior = RegistrationScaffold.rememberTopBarScrollBehavior()
-
-  OnePaneRegistrationScaffold(
-    params = params,
-    topBar = { BackTopAppBar(scrollBehavior = topBarScrollBehavior, onBackClick = { onEvent(SignalLoginScreenEvents.BackClicked) }) },
-    content = { paddingValues ->
-      Column(
-        horizontalAlignment = Alignment.CenterHorizontally,
-        modifier = Modifier
-          .fillMaxSize()
-          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
-          .verticalScroll(scrollState)
-          .padding(paddingValues)
-      ) {
-        Header()
-
-        Spacer(modifier = Modifier.height(32.dp))
-
-        AccountKeyTextField(state = state, onEvent = onEvent)
-      }
-    },
-    footer = { Footer(params, state, scrollState.canScrollForward, onEvent) }
-  )
-}
-
-@OptIn(ExperimentalMaterial3Api::class)
-@Composable
-private fun TwoPaneLayout(
-  params: RegistrationScaffold.Params.TwoPane,
-  state: SignalLoginState,
-  onEvent: (SignalLoginScreenEvents) -> Unit
-) {
-  val firstPaneScrollState = rememberScrollState()
-  val secondPaneScrollState = rememberScrollState()
-  val topBarScrollBehavior = RegistrationScaffold.rememberTopBarScrollBehavior()
-
-  TwoPaneRegistrationScaffold(
-    params = params,
-    topBar = { BackTopAppBar(scrollBehavior = topBarScrollBehavior, onBackClick = { onEvent(SignalLoginScreenEvents.BackClicked) }) },
-    firstPane = { paddingValues ->
-      Column(
-        horizontalAlignment = Alignment.CenterHorizontally,
-        modifier = Modifier
-          .weight(1f)
-          .fillMaxHeight()
-          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
-          .verticalScroll(firstPaneScrollState)
-          .padding(paddingValues)
-      ) {
-        Header(twoPane = true)
-      }
-    },
-    secondPane = { paddingValues ->
-      Column(
-        verticalArrangement = Arrangement.Center,
-        modifier = Modifier
-          .weight(1f)
-          .fillMaxHeight()
-          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
-          .verticalScroll(secondPaneScrollState)
-          .padding(paddingValues)
-      ) {
-        AccountKeyTextField(state = state, onEvent = onEvent)
-      }
-    },
-    footer = { Footer(params, state, firstPaneScrollState.canScrollForward || secondPaneScrollState.canScrollForward, onEvent) }
-  )
-}
-
-@Composable
-private fun Header(twoPane: Boolean = false) {
-  Image(
-    painter = painterResource(R.drawable.image_signal_login_ring),
-    contentDescription = null,
-    modifier = Modifier.size(64.dp)
-  )
-
-  Spacer(modifier = Modifier.height(20.dp))
-
-  Text(
-    text = stringResource(R.string.SignalLoginScreen__signal_login),
-    style = if (twoPane) MaterialTheme.typography.headlineLarge else MaterialTheme.typography.headlineMedium,
-    textAlign = TextAlign.Center,
-    modifier = Modifier
-      .fillMaxWidth()
-      .attachDebugLogHelper()
-  )
-
-  Spacer(modifier = Modifier.height(12.dp))
-
-  Text(
-    text = stringResource(R.string.SignalLoginScreen__enter_your_32_character_account_key),
-    style = if (twoPane) MaterialTheme.typography.titleMedium.copy(fontWeight = FontWeight.Normal) else MaterialTheme.typography.bodyLarge,
-    color = MaterialTheme.colorScheme.onSurfaceVariant,
-    textAlign = TextAlign.Center,
-    modifier = Modifier.fillMaxWidth()
-  )
-}
-
-@Composable
-private fun AccountKeyTextField(
-  state: SignalLoginState,
-  onEvent: (SignalLoginScreenEvents) -> Unit
-) {
-  val focusRequester = remember { FocusRequester() }
-  var requestFocus by remember { mutableStateOf(true) }
-  val keyboardController = LocalSoftwareKeyboardController.current
-
-  TextField(
-    value = state.accountKey,
-    onValueChange = { onEvent(SignalLoginScreenEvents.AccountKeyChanged(it)) },
-    label = { Text(stringResource(R.string.SignalLoginScreen__account_key)) },
-    enabled = !state.isSubmitting,
-    singleLine = true,
-    textStyle = MaterialTheme.typography.bodyLarge.copy(
-      fontFamily = MonoTypeface.fontFamily(),
-      fontSize = 18.sp,
-      letterSpacing = 1.44.sp
-    ),
-    colors = TextFieldDefaults.colors(
-      unfocusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
-      focusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
-      errorContainerColor = MaterialTheme.colorScheme.surfaceVariant
-    ),
-    keyboardOptions = KeyboardOptions(
-      keyboardType = KeyboardType.Password,
-      capitalization = KeyboardCapitalization.None,
-      imeAction = ImeAction.Next,
-      autoCorrectEnabled = false
-    ),
-    keyboardActions = KeyboardActions(
-      onNext = {
-        if (state.isNextEnabled) {
-          keyboardController?.hide()
-          onEvent(SignalLoginScreenEvents.NextClicked)
-        }
-      }
-    ),
-    supportingText = {
-      when (val error = state.accountKeyError) {
-        is AccountKeyError.TooLong -> Text(stringResource(R.string.SignalLoginScreen__too_long, error.count, SignalLoginState.ACCOUNT_KEY_LENGTH))
-        is AccountKeyError.Invalid -> Text(stringResource(R.string.SignalLoginScreen__invalid_account_key))
-        is AccountKeyError.Incorrect -> Text(stringResource(R.string.SignalLoginScreen__incorrect_account_key))
-        null -> {}
-      }
-    },
-    isError = state.accountKeyError != null,
-    visualTransformation = AccountKeyVisualTransformation,
-    modifier = Modifier
-      .fillMaxWidth()
-      .testTag(TestTags.SIGNAL_LOGIN_ACCOUNT_KEY_FIELD)
-      .focusRequester(focusRequester)
-      .onGloballyPositioned {
-        if (requestFocus) {
-          focusRequester.requestFocus()
-          requestFocus = false
-        }
-      }
-  )
-}
-
-@Composable
-private fun Footer(
-  params: RegistrationScaffold.Params,
-  state: SignalLoginState,
-  isElevated: Boolean,
-  onEvent: (SignalLoginScreenEvents) -> Unit
-) {
-  RegistrationScaffold.FooterSurface(isElevated = isElevated) {
-    Row(
-      verticalAlignment = Alignment.CenterVertically,
-      modifier = Modifier
-        .fillMaxWidth()
-        .padding(params.footerPadding)
-    ) {
-      Box(
-        contentAlignment = Alignment.CenterStart,
-        modifier = Modifier.weight(1f)
-      ) {
-        NeedHelpButton(onEvent)
-      }
-
-      Box(
-        contentAlignment = Alignment.CenterEnd,
-        modifier = Modifier.weight(1f)
-      ) {
-        NextButton(state, onEvent)
-      }
-    }
-  }
-}
-
-@Composable
-private fun NeedHelpButton(onEvent: (SignalLoginScreenEvents) -> Unit) {
-  TextButton(
-    shape = RoundedCornerShape(0.dp),
-    onClick = { onEvent(SignalLoginScreenEvents.NeedHelpClicked) },
-    modifier = Modifier.testTag(TestTags.SIGNAL_LOGIN_NEED_HELP_BUTTON)
-  ) {
-    Text(text = stringResource(R.string.SignalLoginScreen__need_help))
-  }
-}
-
-@Composable
-private fun NextButton(state: SignalLoginState, onEvent: (SignalLoginScreenEvents) -> Unit) {
-  Buttons.LargeTonal(
-    enabled = state.isNextEnabled,
-    onClick = { onEvent(SignalLoginScreenEvents.NextClicked) },
-    modifier = Modifier.testTag(TestTags.SIGNAL_LOGIN_NEXT_BUTTON)
-  ) {
-    if (state.isSubmitting) {
-      CircularProgressIndicator(
-        strokeWidth = 3.dp,
-        color = MaterialTheme.colorScheme.primary,
-        modifier = Modifier.size(24.dp)
-      )
-    } else {
-      Text(text = stringResource(R.string.SignalLoginScreen__next))
-    }
-  }
-}
-
-/**
- * Renders an account key the way its ACI is normally written: uppercased and split into 8-4-4-4-12 groups by dashes.
- * The dashes are display-only, so what the view model sees is always the unformatted key.
- */
-internal object AccountKeyVisualTransformation : VisualTransformation {
-
-  /** Offsets in the raw key that a dash is inserted in front of. */
-  private val DASH_OFFSETS = intArrayOf(8, 12, 16, 20)
-
-  override fun filter(text: AnnotatedString): TransformedText {
-    val transformed = buildString {
-      for ((index, character) in text.text.withIndex()) {
-        if (index in DASH_OFFSETS) {
-          append('-')
-        }
-        append(character.uppercaseChar())
-      }
-    }
-
-    return TransformedText(
-      text = AnnotatedString(transformed),
-      offsetMapping = AccountKeyOffsetMapping(text.length)
-    )
-  }
-
-  /**
-   * A dash is only present if the key is long enough to have a character after it, so [inputLength] decides which of
-   * [DASH_OFFSETS] actually made it into the transformed text.
-   */
-  private class AccountKeyOffsetMapping(private val inputLength: Int) : OffsetMapping {
-    override fun originalToTransformed(offset: Int): Int = offset + DASH_OFFSETS.count { it <= offset && it < inputLength }
-
-    override fun transformedToOriginal(offset: Int): Int = offset - DASH_OFFSETS.withIndex().count { (index, dashOffset) -> dashOffset < inputLength && dashOffset + index < offset }
-  }
-}
-
-@AllDevicePreviews
-@Composable
-private fun SignalLoginScreenPreview() {
-  Previews.Preview {
-    SignalLoginScreen(
-      state = SignalLoginState(),
-      onEvent = {}
-    )
-  }
-}
-
-@AllDevicePreviews
-@Composable
-private fun SignalLoginScreenFilledPreview() {
-  Previews.Preview {
-    SignalLoginScreen(
-      state = SignalLoginState(accountKey = "a6b284822e3283d07f2391360a4c2b91"),
-      onEvent = {}
-    )
-  }
-}
-
-@AllDevicePreviews
-@Composable
-private fun SignalLoginScreenSubmittingPreview() {
-  Previews.Preview {
-    SignalLoginScreen(
-      state = SignalLoginState(
-        accountKey = "a6b284822e3283d07f2391360a4c2b91",
-        isSubmitting = true
-      ),
-      onEvent = {}
-    )
-  }
-}
-
-@AllDevicePreviews
-@Composable
-private fun SignalLoginScreenErrorPreview() {
-  Previews.Preview {
-    SignalLoginScreen(
-      state = SignalLoginState(
-        accountKey = "a6b284822e3283d07f2391360a4c2b91",
-        accountKeyError = AccountKeyError.Incorrect
-      ),
-      onEvent = {}
-    )
-  }
-}

feature/registration/src/main/java/org/signal/registration/screens/signallogin/SignalLoginScreenActions.kt

@@ -1,11 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-sealed interface SignalLoginScreenActions {
-  /** Open the article explaining where to find your account key. */
-  data object OpenNeedHelpArticle : SignalLoginScreenActions
-}

feature/registration/src/main/java/org/signal/registration/screens/signallogin/SignalLoginScreenEvents.kt

@@ -1,30 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-import org.signal.core.util.censor
-
-sealed class SignalLoginScreenEvents {
-  /** The user tapped the back arrow. */
-  data object BackClicked : SignalLoginScreenEvents()
-
-  /** The user edited the account key field. Carries the raw text, formatting and all. */
-  data class AccountKeyChanged(val value: String) : SignalLoginScreenEvents() {
-    override fun toString(): String = "AccountKeyChanged(value=${value.censor()})"
-  }
-
-  /** The user tapped "Need help?". */
-  data object NeedHelpClicked : SignalLoginScreenEvents()
-
-  /** The user submitted the account key, either with the next button or the keyboard's next action. */
-  data object NextClicked : SignalLoginScreenEvents()
-
-  /** The user dismissed the network error dialog. */
-  data object NetworkErrorDialogDismissed : SignalLoginScreenEvents()
-
-  /** The user dismissed the unknown error dialog. */
-  data object UnknownErrorDialogDismissed : SignalLoginScreenEvents()
-}

feature/registration/src/main/java/org/signal/registration/screens/signallogin/SignalLoginState.kt

@@ -1,50 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-import org.signal.core.util.censor
-
-/**
- * State for the screen where a user who already owns a Signal Login types in their account key to log in.
- *
- * [accountKey] holds the key without any of the formatting the user sees: the screen renders the dashes and
- * uppercasing itself, so what is stored here is always the raw lowercase value.
- */
-data class SignalLoginState(
-  val accountKey: String = "",
-  val accountKeyError: AccountKeyError? = null,
-  val isSubmitting: Boolean = false,
-  val dialogs: Dialogs = Dialogs()
-) {
-
-  /** Whether the entered key is complete and well-formed enough to send to the service. */
-  val isNextEnabled: Boolean
-    get() = accountKey.length == ACCOUNT_KEY_LENGTH && accountKeyError == null && !isSubmitting
-
-  override fun toString(): String = "SignalLoginState(accountKey=${accountKey.censor()}, accountKeyError=$accountKeyError, isSubmitting=$isSubmitting, dialogs=$dialogs)"
-
-  data class Dialogs(
-    val networkError: Boolean = false,
-    val unknownError: Boolean = false
-  )
-
-  companion object {
-    /** An account key is an ACI with its dashes removed, so it is always this many hex characters. */
-    const val ACCOUNT_KEY_LENGTH = 32
-  }
-}
-
-/** Why the entered account key can't be submitted. Shown beneath the text field rather than in a dialog. */
-sealed interface AccountKeyError {
-  /** More than [SignalLoginState.ACCOUNT_KEY_LENGTH] characters were entered. */
-  data class TooLong(val count: Int) : AccountKeyError
-
-  /** The entered text contains characters that can't appear in an account key. */
-  data object Invalid : AccountKeyError
-
-  /** The service didn't recognize the entered account key. */
-  data object Incorrect : AccountKeyError
-}

feature/registration/src/main/java/org/signal/registration/screens/signallogin/SignalLoginViewModel.kt

@@ -1,118 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-import androidx.annotation.VisibleForTesting
-import androidx.lifecycle.ViewModel
-import androidx.lifecycle.ViewModelProvider
-import androidx.lifecycle.viewModelScope
-import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.asStateFlow
-import kotlinx.coroutines.flow.launchIn
-import kotlinx.coroutines.flow.onEach
-import kotlinx.coroutines.flow.receiveAsFlow
-import org.signal.core.ui.compose.EventDrivenViewModel
-import org.signal.core.util.logging.Log
-import org.signal.registration.RegistrationFlowEvent
-import org.signal.registration.RegistrationRepository
-import org.signal.registration.screens.util.navigateBack
-
-/**
- * View model for [SignalLoginScreen].
- *
- * Logging in with an account key requires an endpoint that doesn't exist yet, so [SignalLoginScreenEvents.NextClicked]
- * is deliberately left as a stub. Everything the screen needs to validate and format what the user types is here.
- */
-class SignalLoginViewModel(
-  private val repository: RegistrationRepository,
-  private val parentEventEmitter: (RegistrationFlowEvent) -> Unit
-) : EventDrivenViewModel<SignalLoginScreenEvents>(TAG) {
-
-  companion object {
-    private val TAG = Log.tag(SignalLoginViewModel::class)
-
-    /** Formatting the user may have pasted along with the key, which we accept and discard. */
-    private val FORMATTING_CHARACTERS = Regex("""[\s-]""")
-
-    private fun Char.isAccountKeyCharacter(): Boolean = this in '0'..'9' || this in 'a'..'f'
-  }
-
-  private val _state = MutableStateFlow(SignalLoginState())
-  val state: StateFlow<SignalLoginState> = _state.asStateFlow()
-
-  private val _actions = Channel<SignalLoginScreenActions>(Channel.BUFFERED)
-  val actions: Flow<SignalLoginScreenActions> = _actions.receiveAsFlow()
-
-  init {
-    _state
-      .onEach { Log.d(TAG, "[State] $it") }
-      .launchIn(viewModelScope)
-  }
-
-  override suspend fun processEvent(event: SignalLoginScreenEvents) {
-    applyEvent(_state.value, event, parentEventEmitter) { _state.value = it }
-  }
-
-  @VisibleForTesting
-  suspend fun applyEvent(
-    state: SignalLoginState,
-    event: SignalLoginScreenEvents,
-    parentEventEmitter: (RegistrationFlowEvent) -> Unit,
-    stateEmitter: (SignalLoginState) -> Unit
-  ) {
-    when (event) {
-      is SignalLoginScreenEvents.BackClicked -> {
-        parentEventEmitter.navigateBack()
-      }
-
-      is SignalLoginScreenEvents.AccountKeyChanged -> {
-        val accountKey = event.value.replace(FORMATTING_CHARACTERS, "").lowercase()
-        stateEmitter(state.copy(accountKey = accountKey, accountKeyError = validate(accountKey)))
-      }
-
-      is SignalLoginScreenEvents.NeedHelpClicked -> {
-        _actions.trySend(SignalLoginScreenActions.OpenNeedHelpArticle)
-      }
-
-      is SignalLoginScreenEvents.NextClicked -> {
-        Log.i(TAG, "Next clicked, but logging in with an account key isn't implemented yet.")
-      }
-
-      is SignalLoginScreenEvents.NetworkErrorDialogDismissed -> {
-        stateEmitter(state.copy(dialogs = state.dialogs.copy(networkError = false)))
-      }
-
-      is SignalLoginScreenEvents.UnknownErrorDialogDismissed -> {
-        stateEmitter(state.copy(dialogs = state.dialogs.copy(unknownError = false)))
-      }
-    }
-  }
-
-  /**
-   * Checks an already-normalized [accountKey]. A key that is merely incomplete isn't an error — the next button stays
-   * disabled until it is the right length, without nagging the user as they type.
-   */
-  private fun validate(accountKey: String): AccountKeyError? {
-    return when {
-      accountKey.length > SignalLoginState.ACCOUNT_KEY_LENGTH -> AccountKeyError.TooLong(accountKey.length)
-      accountKey.any { !it.isAccountKeyCharacter() } -> AccountKeyError.Invalid
-      else -> null
-    }
-  }
-
-  class Factory(
-    private val repository: RegistrationRepository,
-    private val parentEventEmitter: (RegistrationFlowEvent) -> Unit
-  ) : ViewModelProvider.Factory {
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : ViewModel> create(modelClass: Class<T>): T {
-      return SignalLoginViewModel(repository, parentEventEmitter) as T
-    }
-  }
-}

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/AccountIdFormat.kt

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import org.signal.core.models.ServiceId.ACI
+
+/**
+ * The 8-4-4-4-12 layout an account ID shares with the [ACI] it is written from.
+ * Exists to support formatting ACI's as-you-type.
+ */
+internal object AccountIdFormat {
+
+  /** Offsets in a raw account ID that a dash is inserted in front of. */
+  private val DASH_OFFSETS = intArrayOf(8, 12, 16, 20)
+
+  /** Rewrites a raw account ID with the dashes a UUID is normally written with. */
+  fun dashed(accountId: String): String {
+    return buildString {
+      for ((index, character) in accountId.withIndex()) {
+        if (index in DASH_OFFSETS) {
+          append('-')
+        }
+        append(character)
+      }
+    }
+  }
+
+  /**
+   * How many dashes [dashed] inserts before [offset] in an ID of [length] characters. A dash is only present if the ID
+   * is long enough to have a character after it, so [length] decides which offsets actually contribute.
+   */
+  fun dashesBeforeRawOffset(offset: Int, length: Int): Int {
+    return DASH_OFFSETS.count { it <= offset && it < length }
+  }
+
+  /** How many dashes precede [offset] in the output of [dashed] for an ID of [length] characters. */
+  fun dashesBeforeDashedOffset(offset: Int, length: Int): Int {
+    return DASH_OFFSETS.withIndex().count { (index, dashOffset) -> dashOffset < length && dashOffset + index < offset }
+  }
+
+  /** Parses a complete raw account ID as the [ACI] it stands for. Null if it isn't a valid ACI. */
+  fun toAciOrNull(accountId: String): ACI? {
+    if (accountId.length != SignalLoginCredentialEntryState.ACCOUNT_ID_LENGTH) {
+      return null
+    }
+
+    return ACI.parseOrNull(dashed(accountId))
+  }
+}

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreen.kt

@@ -0,0 +1,493 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TextField
+import androidx.compose.material3.TextFieldDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.platform.LocalSoftwareKeyboardController
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.OffsetMapping
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.input.TransformedText
+import androidx.compose.ui.text.input.VisualTransformation
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import org.signal.core.ui.compose.AllDevicePreviews
+import org.signal.core.ui.compose.Buttons
+import org.signal.core.ui.compose.Dialogs
+import org.signal.core.ui.compose.Previews
+import org.signal.core.ui.compose.SignalIcons
+import org.signal.passwordmanager.compose.attachPasswordAutoFillHelper
+import org.signal.passwordmanager.compose.passwordAutoFillHelper
+import org.signal.registration.R
+import org.signal.registration.fonts.MonoTypeface
+import org.signal.registration.screens.OnePaneRegistrationScaffold
+import org.signal.registration.screens.RegistrationScaffold
+import org.signal.registration.screens.TwoPaneRegistrationScaffold
+import org.signal.registration.screens.aepentry.AepInput
+import org.signal.registration.screens.aepentry.AepValidationError
+import org.signal.registration.screens.aepentry.AepVisualTransformation
+import org.signal.registration.screens.attachDebugLogHelper
+import org.signal.registration.screens.shared.BackTopAppBar
+import org.signal.registration.test.TestTags
+
+/** How the recovery key is grouped when it is spelled out rather than masked. */
+private const val RECOVERY_KEY_CHUNK_LENGTH = 4
+
+/**
+ * Collects an existing Signal Login -- the account ID and the recovery key that pairs with it -- and logs the user
+ * back in with the two together.
+ */
+@Composable
+fun SignalLoginCredentialEntryScreen(
+  state: SignalLoginCredentialEntryState,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit,
+  modifier: Modifier = Modifier
+) {
+  LoginErrorDialog(state.loginError, onEvent)
+
+  Surface(
+    modifier = modifier
+      .fillMaxSize()
+      .testTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_ENTRY_SCREEN)
+  ) {
+    when (val params = RegistrationScaffold.rememberLayoutParams()) {
+      is RegistrationScaffold.Params.OnePane -> OnePaneLayout(params, state, onEvent)
+      is RegistrationScaffold.Params.TwoPane -> TwoPaneLayout(params, state, onEvent)
+    }
+  }
+}
+
+/**
+ * Shows a dismissable dialog for the login failures the text fields can't express. A rejected pair is surfaced inline
+ * on both fields instead, since either half could be the one at fault.
+ */
+@Composable
+private fun LoginErrorDialog(error: SignalLoginError?, onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit) {
+  val message = when (error) {
+    SignalLoginError.NetworkError -> stringResource(R.string.VerificationCodeScreen__network_error)
+    SignalLoginError.RateLimited -> stringResource(R.string.VerificationCodeScreen__too_many_attempts)
+    SignalLoginError.UnknownError -> stringResource(R.string.VerificationCodeScreen__an_unexpected_error_occurred)
+    null -> null
+  } ?: return
+
+  Dialogs.SimpleMessageDialog(
+    message = message,
+    dismiss = stringResource(android.R.string.ok),
+    onDismiss = { onEvent(SignalLoginCredentialEntryScreenEvents.DismissError) }
+  )
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun OnePaneLayout(
+  params: RegistrationScaffold.Params.OnePane,
+  state: SignalLoginCredentialEntryState,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit
+) {
+  val scrollState = rememberScrollState()
+  val topBarScrollBehavior = RegistrationScaffold.rememberTopBarScrollBehavior()
+
+  OnePaneRegistrationScaffold(
+    params = params,
+    topBar = { BackTopAppBar(scrollBehavior = topBarScrollBehavior, onBackClick = { onEvent(SignalLoginCredentialEntryScreenEvents.BackClicked) }) },
+    content = { paddingValues ->
+      Column(
+        horizontalAlignment = Alignment.CenterHorizontally,
+        modifier = Modifier
+          .fillMaxSize()
+          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
+          .verticalScroll(scrollState)
+          .padding(paddingValues)
+      ) {
+        Header()
+
+        Spacer(modifier = Modifier.height(32.dp))
+
+        CredentialTextFields(state = state, onEvent = onEvent)
+      }
+    },
+    footer = { Footer(params, state, scrollState.canScrollForward, onEvent) }
+  )
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun TwoPaneLayout(
+  params: RegistrationScaffold.Params.TwoPane,
+  state: SignalLoginCredentialEntryState,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit
+) {
+  val firstPaneScrollState = rememberScrollState()
+  val secondPaneScrollState = rememberScrollState()
+  val topBarScrollBehavior = RegistrationScaffold.rememberTopBarScrollBehavior()
+
+  TwoPaneRegistrationScaffold(
+    params = params,
+    topBar = { BackTopAppBar(scrollBehavior = topBarScrollBehavior, onBackClick = { onEvent(SignalLoginCredentialEntryScreenEvents.BackClicked) }) },
+    firstPane = { paddingValues ->
+      Column(
+        horizontalAlignment = Alignment.CenterHorizontally,
+        modifier = Modifier
+          .weight(1f)
+          .fillMaxHeight()
+          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
+          .verticalScroll(firstPaneScrollState)
+          .padding(paddingValues)
+      ) {
+        Header(twoPane = true)
+      }
+    },
+    secondPane = { paddingValues ->
+      Column(
+        verticalArrangement = Arrangement.Center,
+        modifier = Modifier
+          .weight(1f)
+          .fillMaxHeight()
+          .nestedScroll(topBarScrollBehavior.nestedScrollConnection)
+          .verticalScroll(secondPaneScrollState)
+          .padding(paddingValues)
+      ) {
+        CredentialTextFields(state = state, onEvent = onEvent)
+      }
+    },
+    footer = { Footer(params, state, firstPaneScrollState.canScrollForward || secondPaneScrollState.canScrollForward, onEvent) }
+  )
+}
+
+@Composable
+private fun Header(twoPane: Boolean = false) {
+  Image(
+    painter = painterResource(R.drawable.image_signal_login_ring),
+    contentDescription = null,
+    modifier = Modifier.size(64.dp)
+  )
+
+  Spacer(modifier = Modifier.height(20.dp))
+
+  Text(
+    text = stringResource(R.string.SignalLoginCredentialEntryScreen__signal_login),
+    style = if (twoPane) MaterialTheme.typography.headlineLarge else MaterialTheme.typography.headlineMedium,
+    textAlign = TextAlign.Center,
+    modifier = Modifier
+      .fillMaxWidth()
+      .attachDebugLogHelper()
+  )
+
+  Spacer(modifier = Modifier.height(12.dp))
+
+  Text(
+    text = stringResource(R.string.SignalLoginCredentialEntryScreen__enter_your_account_id_followed_by_your_recovery_key),
+    style = if (twoPane) MaterialTheme.typography.titleMedium.copy(fontWeight = FontWeight.Normal) else MaterialTheme.typography.bodyLarge,
+    color = MaterialTheme.colorScheme.onSurfaceVariant,
+    textAlign = TextAlign.Center,
+    modifier = Modifier.fillMaxWidth()
+  )
+}
+
+@Composable
+private fun CredentialTextFields(
+  state: SignalLoginCredentialEntryState,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit
+) {
+  AccountIdTextField(state = state, onEvent = onEvent)
+
+  Spacer(modifier = Modifier.height(12.dp))
+
+  RecoveryKeyTextField(state = state, onEvent = onEvent)
+}
+
+@Composable
+private fun AccountIdTextField(
+  state: SignalLoginCredentialEntryState,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit
+) {
+  TextField(
+    value = state.accountId,
+    onValueChange = { onEvent(SignalLoginCredentialEntryScreenEvents.AccountIdChanged(it)) },
+    label = { Text(stringResource(R.string.SignalLoginCredentialEntryScreen__account_id)) },
+    singleLine = true,
+    textStyle = MaterialTheme.typography.bodyLarge.copy(
+      fontFamily = MonoTypeface.fontFamily(),
+      fontSize = 18.sp,
+      letterSpacing = 1.44.sp
+    ),
+    colors = TextFieldDefaults.colors(
+      unfocusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
+      focusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
+      errorContainerColor = MaterialTheme.colorScheme.surfaceVariant
+    ),
+    keyboardOptions = KeyboardOptions(
+      keyboardType = KeyboardType.Password,
+      capitalization = KeyboardCapitalization.None,
+      imeAction = ImeAction.Next,
+      autoCorrectEnabled = false
+    ),
+    supportingText = {
+      when (val error = state.accountIdError) {
+        is AccountIdError.TooLong -> Text(stringResource(R.string.SignalLoginCredentialEntryScreen__too_long, error.count, SignalLoginCredentialEntryState.ACCOUNT_ID_LENGTH))
+        is AccountIdError.Invalid -> Text(stringResource(R.string.SignalLoginCredentialEntryScreen__invalid_account_id))
+        null -> {}
+      }
+    },
+    isError = state.accountIdError != null || state.areCredentialsIncorrect,
+    visualTransformation = AccountIdVisualTransformation,
+    modifier = Modifier
+      .fillMaxWidth()
+      .testTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_ACCOUNT_ID_FIELD)
+  )
+}
+
+@Composable
+private fun RecoveryKeyTextField(
+  state: SignalLoginCredentialEntryState,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit
+) {
+  val keyboardController = LocalSoftwareKeyboardController.current
+  val autoFillHelper = passwordAutoFillHelper { onEvent(SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged(it)) }
+  val revealed = state.isRecoveryKeyRevealed
+  val visualTransformation = remember(revealed) {
+    if (revealed) AepVisualTransformation(RECOVERY_KEY_CHUNK_LENGTH) else PasswordVisualTransformation()
+  }
+
+  TextField(
+    value = state.recoveryKey.enteredText,
+    onValueChange = {
+      onEvent(SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged(it))
+      autoFillHelper.onValueChanged(it)
+    },
+    label = { Text(stringResource(R.string.SignalLoginCredentialEntryScreen__recovery_key)) },
+    singleLine = !revealed,
+    minLines = if (revealed) 3 else 1,
+    textStyle = MaterialTheme.typography.bodyLarge.copy(
+      fontFamily = MonoTypeface.fontFamily(),
+      lineHeight = 36.sp
+    ),
+    colors = TextFieldDefaults.colors(
+      unfocusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
+      focusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
+      errorContainerColor = MaterialTheme.colorScheme.surfaceVariant
+    ),
+    keyboardOptions = KeyboardOptions(
+      keyboardType = KeyboardType.Password,
+      capitalization = KeyboardCapitalization.None,
+      imeAction = ImeAction.Done,
+      autoCorrectEnabled = false
+    ),
+    keyboardActions = KeyboardActions(
+      onDone = {
+        if (state.isNextEnabled) {
+          keyboardController?.hide()
+          onEvent(SignalLoginCredentialEntryScreenEvents.NextClicked)
+        }
+      }
+    ),
+    trailingIcon = { RevealRecoveryKeyButton(revealed, onEvent) },
+    supportingText = {
+      val error = state.recoveryKey.error
+      when {
+        state.areCredentialsIncorrect -> Text(stringResource(R.string.SignalLoginCredentialEntryScreen__incorrect_account_id_or_recovery_key))
+        error is AepValidationError.TooLong -> Text(stringResource(R.string.EnterAepScreen__too_long, error.count, error.max))
+        error != null -> Text(stringResource(R.string.EnterAepScreen__invalid_recovery_key))
+      }
+    },
+    isError = state.recoveryKey.error != null || state.areCredentialsIncorrect,
+    visualTransformation = visualTransformation,
+    modifier = Modifier
+      .fillMaxWidth()
+      .testTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_RECOVERY_KEY_FIELD)
+      .attachPasswordAutoFillHelper(autoFillHelper)
+  )
+}
+
+@Composable
+private fun RevealRecoveryKeyButton(revealed: Boolean, onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit) {
+  IconButton(
+    onClick = { onEvent(SignalLoginCredentialEntryScreenEvents.RecoveryKeyVisibilityToggled) },
+    modifier = Modifier.testTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_REVEAL_RECOVERY_KEY_BUTTON)
+  ) {
+    Icon(
+      painter = if (revealed) SignalIcons.VisibleSlash.painter else SignalIcons.Visible.painter,
+      contentDescription = stringResource(
+        if (revealed) R.string.SignalLoginCredentialEntryScreen__hide_recovery_key else R.string.SignalLoginCredentialEntryScreen__show_recovery_key
+      )
+    )
+  }
+}
+
+@Composable
+private fun Footer(
+  params: RegistrationScaffold.Params,
+  state: SignalLoginCredentialEntryState,
+  isElevated: Boolean,
+  onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit
+) {
+  RegistrationScaffold.FooterSurface(isElevated = isElevated) {
+    Row(
+      verticalAlignment = Alignment.CenterVertically,
+      modifier = Modifier
+        .fillMaxWidth()
+        .padding(params.footerPadding)
+    ) {
+      Box(
+        contentAlignment = Alignment.CenterStart,
+        modifier = Modifier.weight(1f)
+      ) {
+        NeedHelpButton(onEvent)
+      }
+
+      Box(
+        contentAlignment = Alignment.CenterEnd,
+        modifier = Modifier.weight(1f)
+      ) {
+        NextButton(state, onEvent)
+      }
+    }
+  }
+}
+
+@Composable
+private fun NeedHelpButton(onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit) {
+  TextButton(
+    shape = RoundedCornerShape(0.dp),
+    onClick = { onEvent(SignalLoginCredentialEntryScreenEvents.NeedHelpClicked) },
+    modifier = Modifier.testTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEED_HELP_BUTTON)
+  ) {
+    Text(text = stringResource(R.string.SignalLoginCredentialEntryScreen__need_help))
+  }
+}
+
+@Composable
+private fun NextButton(state: SignalLoginCredentialEntryState, onEvent: (SignalLoginCredentialEntryScreenEvents) -> Unit) {
+  Buttons.LargeTonal(
+    enabled = state.isNextEnabled,
+    onClick = { onEvent(SignalLoginCredentialEntryScreenEvents.NextClicked) },
+    modifier = Modifier.testTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON)
+  ) {
+    if (state.isLoggingIn) {
+      CircularProgressIndicator(
+        modifier = Modifier.size(24.dp),
+        strokeWidth = 3.dp,
+        color = MaterialTheme.colorScheme.primary
+      )
+    } else {
+      Text(text = stringResource(R.string.SignalLoginCredentialEntryScreen__next))
+    }
+  }
+}
+
+/**
+ * Renders an account ID the way an ACI is normally written: uppercased and split into 8-4-4-4-12 groups by dashes.
+ * The dashes are display-only, so what the view model sees is always the unformatted ID.
+ */
+internal object AccountIdVisualTransformation : VisualTransformation {
+
+  override fun filter(text: AnnotatedString): TransformedText {
+    return TransformedText(
+      text = AnnotatedString(AccountIdFormat.dashed(text.text).uppercase()),
+      offsetMapping = AccountIdOffsetMapping(text.length)
+    )
+  }
+
+  private class AccountIdOffsetMapping(private val inputLength: Int) : OffsetMapping {
+    override fun originalToTransformed(offset: Int): Int = offset + AccountIdFormat.dashesBeforeRawOffset(offset, inputLength)
+
+    override fun transformedToOriginal(offset: Int): Int = offset - AccountIdFormat.dashesBeforeDashedOffset(offset, inputLength)
+  }
+}
+
+@AllDevicePreviews
+@Composable
+private fun SignalLoginCredentialEntryScreenPreview() {
+  Previews.Preview {
+    SignalLoginCredentialEntryScreen(
+      state = SignalLoginCredentialEntryState(),
+      onEvent = {}
+    )
+  }
+}
+
+@AllDevicePreviews
+@Composable
+private fun SignalLoginCredentialEntryScreenFilledPreview() {
+  Previews.Preview {
+    SignalLoginCredentialEntryScreen(
+      state = SignalLoginCredentialEntryState(
+        accountId = "a6b284822e3283d07f2391360a4c2b91",
+        recoveryKey = AepInput.from("uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t")
+      ),
+      onEvent = {}
+    )
+  }
+}
+
+@AllDevicePreviews
+@Composable
+private fun SignalLoginCredentialEntryScreenRevealedPreview() {
+  Previews.Preview {
+    SignalLoginCredentialEntryScreen(
+      state = SignalLoginCredentialEntryState(
+        accountId = "a6b284822e3283d07f2391360a4c2b91",
+        recoveryKey = AepInput.from("uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"),
+        isRecoveryKeyRevealed = true
+      ),
+      onEvent = {}
+    )
+  }
+}
+
+@AllDevicePreviews
+@Composable
+private fun SignalLoginCredentialEntryScreenErrorPreview() {
+  Previews.Preview {
+    SignalLoginCredentialEntryScreen(
+      state = SignalLoginCredentialEntryState(
+        accountId = "a6b284822e3283d07f2391360a4c2b91",
+        recoveryKey = AepInput.from("uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"),
+        areCredentialsIncorrect = true
+      ),
+      onEvent = {}
+    )
+  }
+}

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenActions.kt

@@ -0,0 +1,11 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+sealed interface SignalLoginCredentialEntryScreenActions {
+  /** Open the article explaining where to find your Signal Login. */
+  data object OpenNeedHelpArticle : SignalLoginCredentialEntryScreenActions
+}

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenEvents.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import org.signal.core.util.censor
+
+sealed class SignalLoginCredentialEntryScreenEvents {
+  /** The user tapped the back arrow. */
+  data object BackClicked : SignalLoginCredentialEntryScreenEvents()
+
+  /** The user edited the account ID field. Carries the raw text, formatting and all. */
+  data class AccountIdChanged(val value: String) : SignalLoginCredentialEntryScreenEvents() {
+    override fun toString(): String = "AccountIdChanged(value=${value.censor()})"
+  }
+
+  /** The user edited the recovery key field. Carries the raw text, formatting and all. */
+  data class RecoveryKeyChanged(val value: String) : SignalLoginCredentialEntryScreenEvents() {
+    override fun toString(): String = "RecoveryKeyChanged(value=${value.censor()})"
+  }
+
+  /** The user tapped the eye button that switches the recovery key between masked and spelled out. */
+  data object RecoveryKeyVisibilityToggled : SignalLoginCredentialEntryScreenEvents()
+
+  /** The user tapped "Need help?". */
+  data object NeedHelpClicked : SignalLoginCredentialEntryScreenEvents()
+
+  /** The user submitted the login, either with the next button or the keyboard's done action. */
+  data object NextClicked : SignalLoginCredentialEntryScreenEvents()
+
+  /** The user dismissed the login error dialog. */
+  data object DismissError : SignalLoginCredentialEntryScreenEvents()
+}

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryState.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import org.signal.core.util.censor
+import org.signal.registration.screens.aepentry.AepInput
+
+/**
+ * State for the screen where a user who already owns a Signal Login types both halves of it in: the account ID and the
+ * recovery key that pairs with it.
+ *
+ * [accountId] holds the ID without any of the formatting the user sees: the screen renders the dashes and the
+ * uppercasing itself, so what is stored here is always the raw lowercase value.
+ */
+data class SignalLoginCredentialEntryState(
+  val accountId: String = "",
+  val accountIdError: AccountIdError? = null,
+  val recoveryKey: AepInput = AepInput(),
+  /** Whether the recovery key is spelled out rather than masked like a password. */
+  val isRecoveryKeyRevealed: Boolean = false,
+  /** The service rejected the pair. Either half could be at fault, so both fields are flagged rather than just one. */
+  val areCredentialsIncorrect: Boolean = false,
+  val isLoggingIn: Boolean = false,
+  val loginError: SignalLoginError? = null
+) {
+
+  /** Whether both halves of the login are complete and well-formed enough to attempt. */
+  val isNextEnabled: Boolean
+    get() = accountId.length == ACCOUNT_ID_LENGTH &&
+      accountIdError == null &&
+      recoveryKey.isValid &&
+      recoveryKey.error == null &&
+      !areCredentialsIncorrect &&
+      !isLoggingIn
+
+  override fun toString(): String = "SignalLoginCredentialEntryState(accountId=${accountId.censor()}, accountIdError=$accountIdError, recoveryKey=$recoveryKey, isRecoveryKeyRevealed=$isRecoveryKeyRevealed, areCredentialsIncorrect=$areCredentialsIncorrect, isLoggingIn=$isLoggingIn, loginError=$loginError)"
+
+  companion object {
+    /** An account ID is an ACI with its dashes removed, so it is always this many hex characters. */
+    const val ACCOUNT_ID_LENGTH = 32
+  }
+}
+
+/** Why the entered account ID can't be submitted. Shown beneath the text field rather than in a dialog. */
+sealed interface AccountIdError {
+  /** More than [SignalLoginCredentialEntryState.ACCOUNT_ID_LENGTH] characters were entered. */
+  data class TooLong(val count: Int) : AccountIdError
+
+  /** The entered text contains characters that can't appear in an account ID. */
+  data object Invalid : AccountIdError
+}
+
+/** A login failure that the text fields can't express, so it gets a dialog instead. */
+sealed interface SignalLoginError {
+  data object RateLimited : SignalLoginError
+  data object NetworkError : SignalLoginError
+  data object UnknownError : SignalLoginError
+}

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryViewModel.kt

@@ -0,0 +1,253 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import androidx.annotation.VisibleForTesting
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.receiveAsFlow
+import org.signal.core.models.AccountEntropyPool
+import org.signal.core.models.ServiceId.ACI
+import org.signal.core.ui.compose.EventDrivenViewModel
+import org.signal.core.util.logging.Log
+import org.signal.libsignal.net.RequestResult
+import org.signal.network.api.RegistrationApiV2.RegisterAccountError
+import org.signal.registration.NetworkController
+import org.signal.registration.RegistrationFlowEvent
+import org.signal.registration.RegistrationRepository
+import org.signal.registration.RegistrationRoute
+import org.signal.registration.RestoreDecision
+import org.signal.registration.screens.aepentry.AepInput
+import org.signal.registration.screens.util.navigateBack
+import org.signal.registration.screens.util.navigateTo
+
+/**
+ * View model for [SignalLoginCredentialEntryScreen], where a user who already owns a Signal Login types in both halves
+ * of it and gets logged back in.
+ */
+class SignalLoginCredentialEntryViewModel(
+  private val repository: RegistrationRepository,
+  private val parentEventEmitter: (RegistrationFlowEvent) -> Unit
+) : EventDrivenViewModel<SignalLoginCredentialEntryScreenEvents>(TAG) {
+
+  companion object {
+    private val TAG = Log.tag(SignalLoginCredentialEntryViewModel::class)
+
+    /** Formatting the user may have pasted along with the account ID, which we accept and discard. */
+    private val FORMATTING_CHARACTERS = Regex("""[\s-]""")
+
+    private fun Char.isAccountIdCharacter(): Boolean = this in '0'..'9' || this in 'a'..'f'
+  }
+
+  private val _state = MutableStateFlow(SignalLoginCredentialEntryState())
+  val state: StateFlow<SignalLoginCredentialEntryState> = _state.asStateFlow()
+
+  private val _actions = Channel<SignalLoginCredentialEntryScreenActions>(Channel.BUFFERED)
+  val actions: Flow<SignalLoginCredentialEntryScreenActions> = _actions.receiveAsFlow()
+
+  init {
+    _state
+      .onEach { Log.d(TAG, "[State] $it") }
+      .launchIn(viewModelScope)
+  }
+
+  override suspend fun processEvent(event: SignalLoginCredentialEntryScreenEvents) {
+    applyEvent(_state.value, event, parentEventEmitter) { _state.value = it }
+  }
+
+  @VisibleForTesting
+  suspend fun applyEvent(
+    state: SignalLoginCredentialEntryState,
+    event: SignalLoginCredentialEntryScreenEvents,
+    parentEventEmitter: (RegistrationFlowEvent) -> Unit,
+    stateEmitter: (SignalLoginCredentialEntryState) -> Unit
+  ) {
+    when (event) {
+      is SignalLoginCredentialEntryScreenEvents.BackClicked -> {
+        parentEventEmitter.navigateBack()
+      }
+
+      is SignalLoginCredentialEntryScreenEvents.AccountIdChanged -> {
+        val accountId = event.value.replace(FORMATTING_CHARACTERS, "").lowercase()
+        stateEmitter(state.copy(accountId = accountId, accountIdError = validateAccountId(accountId), areCredentialsIncorrect = false))
+      }
+
+      is SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged -> {
+        stateEmitter(state.copy(recoveryKey = AepInput.from(event.value, state.recoveryKey.error), areCredentialsIncorrect = false))
+      }
+
+      is SignalLoginCredentialEntryScreenEvents.RecoveryKeyVisibilityToggled -> {
+        stateEmitter(state.copy(isRecoveryKeyRevealed = !state.isRecoveryKeyRevealed))
+      }
+
+      is SignalLoginCredentialEntryScreenEvents.NeedHelpClicked -> {
+        _actions.trySend(SignalLoginCredentialEntryScreenActions.OpenNeedHelpArticle)
+      }
+
+      is SignalLoginCredentialEntryScreenEvents.DismissError -> {
+        stateEmitter(state.copy(loginError = null))
+      }
+
+      is SignalLoginCredentialEntryScreenEvents.NextClicked -> {
+        applyNextClicked(state, parentEventEmitter, stateEmitter)
+      }
+    }
+  }
+
+  private suspend fun applyNextClicked(
+    state: SignalLoginCredentialEntryState,
+    parentEventEmitter: (RegistrationFlowEvent) -> Unit,
+    stateEmitter: (SignalLoginCredentialEntryState) -> Unit
+  ) {
+    val aci = AccountIdFormat.toAciOrNull(state.accountId)
+    if (aci == null) {
+      Log.w(TAG, "[Next] The entered account ID isn't a valid ACI.")
+      stateEmitter(state.copy(accountIdError = AccountIdError.Invalid))
+      return
+    }
+
+    check(state.recoveryKey.isValid) { "Recovery key is not valid, should not have gotten here." }
+
+    val aep = AccountEntropyPool(state.recoveryKey.normalized)
+
+    stateEmitter(state.copy(isLoggingIn = true))
+    parentEventEmitter(RegistrationFlowEvent.UserSuppliedAepSubmitted(aep))
+
+    Log.i(TAG, "[Next] Attempting to log in to ${aci.logString()} with the RRP derived from the entered recovery key.")
+
+    attemptToLogIn(state, aci, aep, provideRegistrationLock = false, parentEventEmitter, stateEmitter)
+  }
+
+  private suspend fun attemptToLogIn(
+    inputState: SignalLoginCredentialEntryState,
+    aci: ACI,
+    aep: AccountEntropyPool,
+    provideRegistrationLock: Boolean,
+    parentEventEmitter: (RegistrationFlowEvent) -> Unit,
+    stateEmitter: (SignalLoginCredentialEntryState) -> Unit
+  ) {
+    val masterKey = aep.deriveMasterKey()
+    val recoveryPassword = masterKey.deriveRegistrationRecoveryPassword()
+    val registrationLock = masterKey.deriveRegistrationLock().takeIf { provideRegistrationLock }
+
+    val result = repository.reRegisterAccountWithoutPhoneNumber(
+      aci = aci,
+      recoveryPassword = recoveryPassword,
+      aep = aep,
+      registrationLock = registrationLock
+    )
+
+    when (result) {
+      is RequestResult.Success -> {
+        Log.i(TAG, "[Next] Successfully logged back in without a phone number.")
+        val (response, keyMaterial, registeredAci) = result.result
+
+        parentEventEmitter(RegistrationFlowEvent.Registered(registeredAci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
+
+        if (response.reregistration) {
+          val hasRemoteBackup = hasRemoteBackup(aep)
+
+          Log.i(TAG, "[Next] Reclaimed an existing account. Letting the user choose how to restore it. hasRemoteBackup: $hasRemoteBackup")
+          stateEmitter(inputState.copy(isLoggingIn = false))
+          parentEventEmitter.navigateTo(RegistrationRoute.ArchiveRestoreSelection.forPostRegisterWithKnownAep(aep, hasRemoteBackup))
+        } else {
+          Log.i(TAG, "[Next] The service reports a brand new account, so there is nothing to restore. Finishing up.")
+          repository.setRestoreDecision(RestoreDecision.NEW_ACCOUNT)
+          repository.restoreAccountRecord()
+          stateEmitter(inputState.copy(isLoggingIn = false))
+          parentEventEmitter(RegistrationFlowEvent.RegistrationComplete)
+        }
+      }
+      is RequestResult.NonSuccess -> {
+        when (val error = result.error) {
+          is RegisterAccountError.RegistrationRecoveryPasswordIncorrect -> {
+            Log.w(TAG, "[Next] RRP incorrect. Either the account ID or the recovery key is wrong. Message: ${error.message}")
+            stateEmitter(inputState.copy(isLoggingIn = false, areCredentialsIncorrect = true))
+          }
+          is RegisterAccountError.RegistrationLock -> {
+            if (provideRegistrationLock) {
+              Log.w(TAG, "[Next] Still registration locked after providing the reglock token derived from the recovery key. Falling back to PIN entry.")
+              stateEmitter(inputState.copy(isLoggingIn = false))
+              parentEventEmitter.navigateTo(
+                RegistrationRoute.PinEntryForRegistrationLock(
+                  timeRemaining = error.data.timeRemaining,
+                  svrCredentials = error.data.svr2Credentials
+                )
+              )
+            } else {
+              Log.w(TAG, "[Next] Registration locked. Retrying with the reglock token derived from the recovery key.")
+              attemptToLogIn(inputState, aci, aep, provideRegistrationLock = true, parentEventEmitter, stateEmitter)
+            }
+          }
+          is RegisterAccountError.RateLimited -> {
+            Log.w(TAG, "[Next] Rate limited (retryAfter: ${error.retryAfter}).")
+            stateEmitter(inputState.copy(isLoggingIn = false, loginError = SignalLoginError.RateLimited))
+          }
+          is RegisterAccountError.SessionNotFoundOrNotVerified -> {
+            error("[Next] Session not found or not verified. This should not happen with RRP-based registration.")
+          }
+          is RegisterAccountError.DeviceTransferPossible -> {
+            error("[Next] Device transfer possible. This should not happen with RRP-based registration.")
+          }
+          is RegisterAccountError.InvalidRequest,
+          is RegisterAccountError.InvalidReceiptCredentialPresentation,
+          RegisterAccountError.TotpMissingOrIncorrect,
+          RegisterAccountError.PostQuantumRatchetRequired -> {
+            Log.w(TAG, "[Next] Unexpected registration error: $error")
+            stateEmitter(inputState.copy(isLoggingIn = false, loginError = SignalLoginError.UnknownError))
+          }
+        }
+      }
+      is RequestResult.RetryableNetworkError -> {
+        Log.w(TAG, "[Next] Network error.", result.networkError)
+        stateEmitter(inputState.copy(isLoggingIn = false, loginError = SignalLoginError.NetworkError))
+      }
+      is RequestResult.ApplicationError -> {
+        Log.w(TAG, "[Next] Application error.", result.cause)
+        stateEmitter(inputState.copy(isLoggingIn = false, loginError = SignalLoginError.UnknownError))
+      }
+    }
+  }
+
+  private suspend fun hasRemoteBackup(aep: AccountEntropyPool): Boolean {
+    val result = repository.getAndMaybeHealRemoteBackupInfo(aep)
+
+    return when {
+      result is RequestResult.Success -> true
+      result is RequestResult.NonSuccess && result.error is NetworkController.GetBackupInfoError.NoBackup -> false
+      else -> {
+        Log.w(TAG, "[hasRemoteBackup] Could not determine whether a remote backup exists ($result). Offering it anyway.")
+        true
+      }
+    }
+  }
+
+  private fun validateAccountId(accountId: String): AccountIdError? {
+    return when {
+      accountId.length > SignalLoginCredentialEntryState.ACCOUNT_ID_LENGTH -> AccountIdError.TooLong(accountId.length)
+      accountId.any { !it.isAccountIdCharacter() } -> AccountIdError.Invalid
+      else -> null
+    }
+  }
+
+  class Factory(
+    private val repository: RegistrationRepository,
+    private val parentEventEmitter: (RegistrationFlowEvent) -> Unit
+  ) : ViewModelProvider.Factory {
+    @Suppress("UNCHECKED_CAST")
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+      return SignalLoginCredentialEntryViewModel(repository, parentEventEmitter) as T
+    }
+  }
+}

feature/registration/src/main/java/org/signal/registration/screens/signalloginpayment/SignalLoginPaymentViewModel.kt

@@ -89,7 +89,7 @@ class SignalLoginPaymentViewModel(
           localState = applyManualReceiptCredentialSubmitted(localState, parentEventEmitter)
           stateEmitter(localState.copy(showSpinner = false))
         } else if (state.selectedOption == SignalLoginPaymentState.Option.ExistingLogin) {
-          parentEventEmitter.navigateTo(RegistrationRoute.SignalLogin)
+          parentEventEmitter.navigateTo(RegistrationRoute.SignalLoginCredentialEntry)
         } else {
           // TODO [phonenumberless] Launch the purchase flow.
           Log.i(TAG, "Continue clicked for ${state.selectedOption}, but the purchase flow isn't implemented yet.")
@@ -134,7 +134,7 @@ class SignalLoginPaymentViewModel(
         Log.i(TAG, "[ManualReceipt] Successfully registered without a phone number.")
         val (response, keyMaterial, aci) = result.result
 
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
         parentEventEmitter.navigateTo(RegistrationRoute.SignalLoginInfo)
         state
       }

feature/registration/src/main/java/org/signal/registration/screens/verificationcode/VerificationCodeViewModel.kt

@@ -372,7 +372,7 @@ class VerificationCodeViewModel(
       is RequestResult.Success -> {
         val (response, keyMaterial, aci) = registerResult.result
 
-        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable))
+        parentEventEmitter(RegistrationFlowEvent.Registered(aci, keyMaterial.accountEntropyPool, response.storageCapable, phoneNumberless = response.e164 == null))
 
         val pendingRestore = pendingRestoreNavigation()
         when {

feature/registration/src/main/java/org/signal/registration/test/TestTags.kt

@@ -57,11 +57,13 @@ object TestTags {
   const val SIGNAL_LOGIN_PAYMENT_CONTINUE_BUTTON = "signal_login_payment_continue_button"
   const val SIGNAL_LOGIN_PAYMENT_RECEIPT_CREDENTIAL_FIELD = "signal_login_payment_receipt_credential_field"
 
-  // Signal Login Screen
-  const val SIGNAL_LOGIN_SCREEN = "signal_login_screen"
-  const val SIGNAL_LOGIN_ACCOUNT_KEY_FIELD = "signal_login_account_key_field"
-  const val SIGNAL_LOGIN_NEED_HELP_BUTTON = "signal_login_need_help_button"
-  const val SIGNAL_LOGIN_NEXT_BUTTON = "signal_login_next_button"
+  // Signal Login Credential Entry Screen
+  const val SIGNAL_LOGIN_CREDENTIAL_ENTRY_SCREEN = "signal_login_credential_entry_screen"
+  const val SIGNAL_LOGIN_CREDENTIAL_ACCOUNT_ID_FIELD = "signal_login_credential_account_id_field"
+  const val SIGNAL_LOGIN_CREDENTIAL_RECOVERY_KEY_FIELD = "signal_login_credential_recovery_key_field"
+  const val SIGNAL_LOGIN_CREDENTIAL_REVEAL_RECOVERY_KEY_BUTTON = "signal_login_credential_reveal_recovery_key_button"
+  const val SIGNAL_LOGIN_CREDENTIAL_NEED_HELP_BUTTON = "signal_login_credential_need_help_button"
+  const val SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON = "signal_login_credential_next_button"
 
   // Signal Login Info Screen
   const val SIGNAL_LOGIN_INFO_SCREEN = "signal_login_info_screen"

feature/registration/src/main/res/values/strings.xml

@@ -242,6 +242,10 @@
     <string name="EnterAepScreen__restore_to_new_account_body">The backup you are restoring was created using a different Signal account. You can restore this backup to a new account, but you will no longer be a member of any groups that were restored.</string>
     <!-- Confirm button label for the restore to new account dialog -->
     <string name="EnterAepScreen__restore">Restore</string>
+    <!-- Title of the dialog shown when the entered recovery key is correct, but the account has no Signal Backup to restore -->
+    <string name="EnterAepScreen__no_backup_found">No backup found</string>
+    <!-- Body of the dialog shown when the entered recovery key is correct, but the account has no Signal Backup to restore -->
+    <string name="EnterAepScreen__no_backup_found_body">Your recovery key is correct, but there\'s no Signal Backup for this account. Go back to choose another way to restore, or continue without restoring.</string>
     <!-- Text shown while preparing the restore -->
     <string name="LocalBackupRestoreScreen__preparing_restore">Preparing restore…</string>
     <!-- Title shown while restore is in progress -->
@@ -654,23 +658,29 @@
     <!-- Error shown when the Signal Login could not be stored in the password manager. -->
     <string name="SignalLoginInfoScreen__your_signal_login_could_not_be_saved">Your Signal Login could not be saved. Please save it manually instead.</string>
 
-    <!-- Signal Login account key entry screen -->
-    <!-- Title of the screen where a user with an existing Signal Login types in their account key. -->
-    <string name="SignalLoginScreen__signal_login">Signal Login</string>
+    <!-- Signal Login credential entry screen -->
+    <!-- Title of the screen where a user with an existing Signal Login types it in to log back in. -->
+    <string name="SignalLoginCredentialEntryScreen__signal_login">Signal Login</string>
     <!-- Description telling the user what to enter to log in. -->
-    <string name="SignalLoginScreen__enter_your_32_character_account_key">Enter your 32-character account key to get started.</string>
-    <!-- Label of the text field the account key is typed into. -->
-    <string name="SignalLoginScreen__account_key">Account key</string>
-    <!-- Button that opens a support article for users who can\'t find their account key. -->
-    <string name="SignalLoginScreen__need_help">Need help?</string>
-    <!-- Action button that submits the entered account key. -->
-    <string name="SignalLoginScreen__next">Next</string>
-    <!-- Error shown when too many characters were entered. First placeholder is how many were entered, second is the maximum. -->
-    <string name="SignalLoginScreen__too_long">Too long. %1$d/%2$d characters.</string>
-    <!-- Error shown when the entered account key contains characters that can\'t appear in one. -->
-    <string name="SignalLoginScreen__invalid_account_key">Invalid account key</string>
-    <!-- Error shown when the service doesn\'t recognize the entered account key. -->
-    <string name="SignalLoginScreen__incorrect_account_key">Incorrect account key</string>
+    <string name="SignalLoginCredentialEntryScreen__enter_your_account_id_followed_by_your_recovery_key">Enter your account ID followed by your recovery key to restore your account.</string>
+    <!-- Label of the text field the account ID is typed into. -->
+    <string name="SignalLoginCredentialEntryScreen__account_id">Account ID</string>
+    <!-- Label of the text field the recovery key is typed into. -->
+    <string name="SignalLoginCredentialEntryScreen__recovery_key">Recovery key</string>
+    <!-- Description of the button that spells out the typed recovery key instead of masking it. -->
+    <string name="SignalLoginCredentialEntryScreen__show_recovery_key">Show recovery key</string>
+    <!-- Description of the button that masks the typed recovery key. -->
+    <string name="SignalLoginCredentialEntryScreen__hide_recovery_key">Hide recovery key</string>
+    <!-- Button that opens a support article for users who can\'t find their Signal Login. -->
+    <string name="SignalLoginCredentialEntryScreen__need_help">Need help?</string>
+    <!-- Action button that submits the entered Signal Login. -->
+    <string name="SignalLoginCredentialEntryScreen__next">Next</string>
+    <!-- Error shown when too many characters were entered in the account ID field. First placeholder is how many were entered, second is the maximum. -->
+    <string name="SignalLoginCredentialEntryScreen__too_long">Too long. %1$d/%2$d characters.</string>
+    <!-- Error shown when the entered account ID contains characters that can\'t appear in one. -->
+    <string name="SignalLoginCredentialEntryScreen__invalid_account_id">Invalid account ID</string>
+    <!-- Error shown when the service rejects the entered login, which means one of the two halves is wrong. -->
+    <string name="SignalLoginCredentialEntryScreen__incorrect_account_id_or_recovery_key">Incorrect account ID or recovery key</string>
 
     <!-- Add username screen -->
     <!-- Title of the screen offering the user an optional username. -->

feature/registration/src/screenshotTest/kotlin/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenScreenshotTests.kt

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import androidx.compose.runtime.Composable
+import com.android.tools.screenshot.PreviewTest
+import org.signal.core.ui.compose.Previews
+import org.signal.core.ui.compose.ScreenshotPreviews
+import org.signal.registration.screens.aepentry.AepInput
+
+class SignalLoginCredentialEntryScreenScreenshotTests {
+
+  companion object {
+    private const val ACCOUNT_ID = "a6b284822e3283d07f2391360a4c2b91"
+    private const val RECOVERY_KEY = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"
+  }
+
+  @PreviewTest
+  @ScreenshotPreviews
+  @Composable
+  fun SignalLoginCredentialEntryScreenPreview() {
+    Previews.Preview {
+      SignalLoginCredentialEntryScreen(
+        state = SignalLoginCredentialEntryState(
+          accountId = ACCOUNT_ID,
+          recoveryKey = AepInput.from(RECOVERY_KEY)
+        ),
+        onEvent = {}
+      )
+    }
+  }
+
+  @PreviewTest
+  @ScreenshotPreviews
+  @Composable
+  fun SignalLoginCredentialEntryScreenRevealedPreview() {
+    Previews.Preview {
+      SignalLoginCredentialEntryScreen(
+        state = SignalLoginCredentialEntryState(
+          accountId = ACCOUNT_ID,
+          recoveryKey = AepInput.from(RECOVERY_KEY),
+          isRecoveryKeyRevealed = true
+        ),
+        onEvent = {}
+      )
+    }
+  }
+}

feature/registration/src/screenshotTestDebug/reference/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenScreenshotTests/SignalLoginCredentialEntryScreenPreview_foldable landscape (day)_41c0d57c_0.png

@@ -0,0 +1,3 @@
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@@ -0,0 +1,3 @@
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+oid sha256:2dd6791f21d969a27078997ac7eb17f2647b836a3d03caf2b897eddd8ff050be
+size 118334

feature/registration/src/screenshotTestDebug/reference/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenScreenshotTests/SignalLoginCredentialEntryScreenRevealedPreview_tablet portrait (day)_ae17fb11_0.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:d45c15675a4c6bd7847421fd7006dbd0cdda2f5f2a6bb73b2eb450bdb6876e05
+size 113490

feature/registration/src/test/java/org/signal/registration/PersistedFlowStateTest.kt

@@ -154,6 +154,24 @@ class PersistedFlowStateTest {
     assertThat(decoded).isEqualTo(state)
   }
 
+  @Test
+  fun `round-trip serialization with SignalLoginCredentialEntry`() {
+    val state = PersistedFlowState(
+      backStack = listOf(
+        RegistrationRoute.Welcome,
+        RegistrationRoute.SignalLoginCredentialEntry
+      ),
+      sessionMetadata = null,
+      sessionE164 = null,
+      doNotAttemptRecoveryPassword = false
+    )
+
+    val encoded = json.encodeToString(PersistedFlowState.serializer(), state)
+    val decoded = json.decodeFromString(PersistedFlowState.serializer(), encoded)
+
+    assertThat(decoded).isEqualTo(state)
+  }
+
   @Test
   fun `deserialization ignores unknown keys for forward compatibility`() {
     val validJson = """{"backStack":[{"type":"org.signal.registration.RegistrationRoute.Welcome"}],"sessionMetadata":null,"sessionE164":null,"doNotAttemptRecoveryPassword":false,"unknownField":"value"}"""
@@ -183,6 +201,7 @@ class PersistedFlowStateTest {
       accountEntropyPool = AccountEntropyPool.generate(),
       aci = ACI.from(UUID.fromString("3f8b6a90-8f9c-4a3e-9c7d-1f2e3a4b5c6d")),
       storageCapable = true,
+      isPhoneNumberlessAccount = true,
       temporaryMasterKey = MasterKey(ByteArray(32)),
       doNotAttemptRecoveryPassword = true,
       lastSmsVerificationCodeRequest = VerificationCodeRequest("+15551234567", 12_345L),
@@ -198,6 +217,7 @@ class PersistedFlowStateTest {
     assertThat(persisted.aci).isEqualTo("3f8b6a90-8f9c-4a3e-9c7d-1f2e3a4b5c6d")
     assertThat(persisted.doNotAttemptRecoveryPassword).isEqualTo(true)
     assertThat(persisted.storageCapable).isEqualTo(true)
+    assertThat(persisted.phoneNumberlessAccount).isEqualTo(true)
     assertThat(persisted.smsVerificationCodeRequest).isEqualTo(VerificationCodeRequest("+15551234567", 12_345L))
     assertThat(persisted.callVerificationCodeRequest).isEqualTo(VerificationCodeRequest("+15551234567", 23_456L))
   }
@@ -222,6 +242,7 @@ class PersistedFlowStateTest {
       aci = "3f8b6a90-8f9c-4a3e-9c7d-1f2e3a4b5c6d",
       doNotAttemptRecoveryPassword = true,
       storageCapable = true,
+      phoneNumberlessAccount = true,
       smsVerificationCodeRequest = VerificationCodeRequest("+15551234567", 12_345L),
       callVerificationCodeRequest = VerificationCodeRequest("+15551234567", 23_456L)
     )
@@ -245,6 +266,7 @@ class PersistedFlowStateTest {
     assertThat(flowState.preExistingRegistrationData).isNull()
     assertThat(flowState.doNotAttemptRecoveryPassword).isEqualTo(true)
     assertThat(flowState.storageCapable).isEqualTo(true)
+    assertThat(flowState.isPhoneNumberlessAccount).isEqualTo(true)
     assertThat(flowState.lastSmsVerificationCodeRequest).isEqualTo(VerificationCodeRequest("+15551234567", 12_345L))
     assertThat(flowState.lastCallVerificationCodeRequest).isEqualTo(VerificationCodeRequest("+15551234567", 23_456L))
   }

feature/registration/src/test/java/org/signal/registration/RegistrationRepositoryTest.kt

@@ -16,11 +16,14 @@ import assertk.assertions.isTrue
 import io.mockk.mockk
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.runTest
+import okio.ByteString.Companion.toByteString
 import org.junit.Before
 import org.junit.Test
 import org.signal.core.models.AccountEntropyPool
+import org.signal.core.models.ServiceId.ACI
 import org.signal.core.util.logging.Log
 import org.signal.libsignal.net.RequestResult
+import org.signal.libsignal.protocol.IdentityKeyPair
 import org.signal.network.api.RegistrationApiV2.SvrCredentials
 import org.signal.registration.NetworkController.GetBackupInfoError
 import org.signal.registration.NetworkController.GetBackupInfoResponse
@@ -30,7 +33,9 @@ import org.signal.registration.NetworkController.RestoreMasterKeyError
 import org.signal.registration.fakes.FakeNetworkController
 import org.signal.registration.fakes.FakeStorageController
 import org.signal.registration.fakes.SystemOutLogger
+import org.signal.registration.proto.AccountData
 import java.io.IOException
+import java.util.UUID
 import kotlin.time.Duration.Companion.seconds
 
 /**
@@ -42,6 +47,7 @@ class RegistrationRepositoryTest {
   private lateinit var networkController: FakeNetworkController
   private lateinit var storageController: FakeStorageController
   private lateinit var repository: RegistrationRepository
+  private lateinit var numberlessRepository: RegistrationRepository
 
   private val aep = AccountEntropyPool.generate()
   private val masterKey = aep.deriveMasterKey()
@@ -59,6 +65,13 @@ class RegistrationRepositoryTest {
       storageController = storageController,
       isLinkAndSyncAvailable = false
     )
+    numberlessRepository = RegistrationRepository(
+      context = mockk<Context>(relaxed = true),
+      networkController = networkController,
+      storageController = storageController,
+      isLinkAndSyncAvailable = false,
+      isPhoneNumberlessRegistrationAvailable = true
+    )
   }
 
   // ==================== getAndMaybeHealRemoteBackupInfo ====================
@@ -190,4 +203,95 @@ class RegistrationRepositoryTest {
     assertThat(storageController.committedData).isNull()
     assertThat(storageController.readInProgressRegistrationData().pin).isEmpty()
   }
+
+  // ==================== registerAccountWithoutPhoneNumber / reRegisterAccountWithoutPhoneNumber ====================
+
+  @Test
+  fun `reRegisterAccountWithoutPhoneNumber sends PNI key material when recovering an account by ACI`() = runTest {
+    networkController.onRegisterAccount = { RequestResult.Success(networkController.registerAccountResponse(e164 = null)) }
+
+    val result = numberlessRepository.reRegisterAccountWithoutPhoneNumber(
+      aci = ACI.from(UUID.randomUUID()),
+      recoveryPassword = masterKey.deriveRegistrationRecoveryPassword(),
+      aep = aep
+    )
+
+    assertThat(result).isInstanceOf(RequestResult.Success::class)
+
+    val pniPreKeys = networkController.lastRegisterAccountRequest?.pniPreKeys
+    assertThat(pniPreKeys).isNotNull()
+    assertThat(networkController.lastRegisterAccountRequest?.pniRegistrationId).isNotNull()
+    assertThat(pniPreKeys!!.identityKey.publicKey.verifySignature(pniPreKeys.signedPreKey.keyPair.publicKey.serialize(), pniPreKeys.signedPreKey.signature)).isTrue()
+    assertThat(pniPreKeys.identityKey.publicKey.verifySignature(pniPreKeys.lastResortKyberPreKey.keyPair.publicKey.serialize(), pniPreKeys.lastResortKyberPreKey.signature)).isTrue()
+  }
+
+  @Test
+  fun `reRegisterAccountWithoutPhoneNumber does not keep the PNI key material it sends when recovering an account by ACI`() = runTest {
+    networkController.onRegisterAccount = { RequestResult.Success(networkController.registerAccountResponse(e164 = null)) }
+
+    numberlessRepository.reRegisterAccountWithoutPhoneNumber(
+      aci = ACI.from(UUID.randomUUID()),
+      recoveryPassword = masterKey.deriveRegistrationRecoveryPassword(),
+      aep = aep
+    )
+
+    val accountData = storageController.committedData?.accountData
+    assertThat(accountData).isNotNull()
+    assertThat(accountData!!.pniIdentityKeyPair.size).isEqualTo(0)
+    assertThat(accountData.pniRegistrationId).isEqualTo(0)
+  }
+
+  @Test
+  fun `reRegisterAccountWithoutPhoneNumber keeps the PNI key material it sends when the reclaimed account has a phone number`() = runTest {
+    networkController.onRegisterAccount = { RequestResult.Success(networkController.registerAccountResponse(e164 = "+15551234567")) }
+
+    numberlessRepository.reRegisterAccountWithoutPhoneNumber(
+      aci = ACI.from(UUID.randomUUID()),
+      recoveryPassword = masterKey.deriveRegistrationRecoveryPassword(),
+      aep = aep
+    )
+
+    val sentPniPreKeys = networkController.lastRegisterAccountRequest!!.pniPreKeys!!
+    val accountData = storageController.committedData?.accountData
+    assertThat(accountData).isNotNull()
+    assertThat(IdentityKeyPair(accountData!!.pniIdentityKeyPair.toByteArray()).publicKey).isEqualTo(sentPniPreKeys.identityKey)
+    assertThat(accountData.pniRegistrationId).isEqualTo(networkController.lastRegisterAccountRequest!!.pniRegistrationId)
+  }
+
+  @Test
+  fun `reRegisterAccountWithoutPhoneNumber clears PNI key material left behind by an abandoned attempt`() = runTest {
+    networkController.onRegisterAccount = { RequestResult.Success(networkController.registerAccountResponse(e164 = null)) }
+    storageController.updateInProgressRegistrationData {
+      accountData = AccountData(
+        pniIdentityKeyPair = IdentityKeyPair.generate().serialize().toByteString(),
+        pniSignedPreKey = "abandoned-signed-pre-key".toByteArray().toByteString(),
+        pniLastResortKyberPreKey = "abandoned-kyber-pre-key".toByteArray().toByteString(),
+        pniRegistrationId = 1234
+      )
+    }
+
+    numberlessRepository.reRegisterAccountWithoutPhoneNumber(
+      aci = ACI.from(UUID.randomUUID()),
+      recoveryPassword = masterKey.deriveRegistrationRecoveryPassword(),
+      aep = aep
+    )
+
+    val accountData = storageController.committedData?.accountData
+    assertThat(accountData).isNotNull()
+    assertThat(accountData!!.pniIdentityKeyPair.size).isEqualTo(0)
+    assertThat(accountData.pniSignedPreKey.size).isEqualTo(0)
+    assertThat(accountData.pniLastResortKyberPreKey.size).isEqualTo(0)
+    assertThat(accountData.pniRegistrationId).isEqualTo(0)
+  }
+
+  @Test
+  fun `registerAccountWithoutPhoneNumber does not send PNI key material when creating a brand new account`() = runTest {
+    networkController.onRegisterAccount = { RequestResult.Success(networkController.registerAccountResponse(e164 = null)) }
+
+    val result = numberlessRepository.registerAccountWithoutPhoneNumber(receiptCredentialPresentation = mockk(relaxed = true))
+
+    assertThat(result).isInstanceOf(RequestResult.Success::class)
+    assertThat(networkController.lastRegisterAccountRequest?.pniPreKeys).isNull()
+    assertThat(networkController.lastRegisterAccountRequest?.pniRegistrationId).isNull()
+  }
 }

feature/registration/src/test/java/org/signal/registration/RegistrationViewModelTest.kt

@@ -286,7 +286,7 @@ class RegistrationViewModelTest {
     val viewModel = RegistrationViewModel(mockRepository, SavedStateHandle())
     advanceUntilIdle()
 
-    viewModel.onEvent(RegistrationFlowEvent.Registered(ACI.from(UUID.randomUUID()), AccountEntropyPool.generate(), storageCapable = false))
+    viewModel.onEvent(RegistrationFlowEvent.Registered(ACI.from(UUID.randomUUID()), AccountEntropyPool.generate(), storageCapable = false, phoneNumberless = false))
     advanceUntilIdle()
 
     coVerify(exactly = 0) { mockRepository.saveFlowState(any()) }
@@ -520,6 +520,27 @@ class RegistrationViewModelTest {
     assertThat(result.backStack).isEqualTo(listOf(remoteRestore))
   }
 
+  @Test
+  fun `applyEvent NavigateToScreen RemoteRestore entered from restore selection keeps backStack`() = runTest(testDispatcher) {
+    coEvery { mockRepository.restoreFlowState() } returns null
+    coEvery { mockRepository.getPreExistingRegistrationData() } returns null
+
+    val viewModel = RegistrationViewModel(mockRepository, SavedStateHandle())
+    advanceUntilIdle()
+
+    val restoreSelection = RegistrationRoute.ArchiveRestoreSelection.forPostRegisterWithKnownAep(AccountEntropyPool.generate(), hasRemoteBackup = true)
+    val initialState = RegistrationFlowState(backStack = listOf(restoreSelection))
+
+    val remoteRestore = RegistrationRoute.RemoteRestore(AccountEntropyPool.generate(), backwardNavigationAllowed = true)
+
+    val result = viewModel.applyEvent(
+      initialState,
+      RegistrationFlowEvent.NavigateToScreen(remoteRestore)
+    )
+
+    assertThat(result.backStack).isEqualTo(listOf(restoreSelection, remoteRestore))
+  }
+
   @Test
   fun `applyEvent NavigateToScreen post-registration ArchiveRestoreSelection clears backStack`() = runTest(testDispatcher) {
     coEvery { mockRepository.restoreFlowState() } returns null
@@ -738,7 +759,7 @@ class RegistrationViewModelTest {
 
     val result = viewModel.applyEvent(
       RegistrationFlowState(),
-      RegistrationFlowEvent.Registered(aci, aep, storageCapable = true)
+      RegistrationFlowEvent.Registered(aci, aep, storageCapable = true, phoneNumberless = false)
     )
 
     assertThat(result.aci).isEqualTo(aci)

feature/registration/src/test/java/org/signal/registration/fakes/FakeNetworkController.kt

@@ -87,7 +87,7 @@ class FakeNetworkController(
   }
 
   data class UpdateSessionRequest(val sessionId: String?, val pushChallengeToken: String?, val captchaToken: String?)
-  data class RegisterAccountRequest(val e164: String?, val sessionId: String?, val recoveryPassword: String?, val registrationLock: String?)
+  data class RegisterAccountRequest(val e164: String?, val sessionId: String?, val recoveryPassword: String?, val registrationLock: String?, val aci: ACI? = null, val pniPreKeys: PreKeyCollection? = null, val pniRegistrationId: Int? = null)
   data class SetPinRequest(val pin: String, val masterKey: MasterKey)
   data class RestoreMasterKeyRequest(val svrCredentials: SvrCredentials, val pin: String)
   data class SetRestoreMethodRequest(val token: String, val method: RestoreMethod)
@@ -275,7 +275,8 @@ class FakeNetworkController(
   ): RegisterAccountResponse {
     return RegisterAccountResponse(
       aci = UUID.randomUUID().toString(),
-      pni = UUID.randomUUID().toString(),
+      // An account with no phone number has no PNI, exactly as the service reports it.
+      pni = if (e164 != null) UUID.randomUUID().toString() else null,
       e164 = e164,
       usernameHash = null,
       usernameLinkHandle = null,
@@ -327,9 +328,10 @@ class FakeNetworkController(
     aciPreKeys: PreKeyCollection,
     pniPreKeys: PreKeyCollection?,
     fcmToken: String?,
-    skipDeviceTransfer: Boolean
+    skipDeviceTransfer: Boolean,
+    aci: ACI?
   ): RequestResult<RegisterAccountResponse, RegisterAccountError> {
-    val request = RegisterAccountRequest(e164, sessionId, recoveryPassword, attributes.registrationLock)
+    val request = RegisterAccountRequest(e164, sessionId, recoveryPassword, attributes.registrationLock, aci, pniPreKeys, attributes.pniRegistrationId)
     lastRegisterAccountRequest = request
     return onRegisterAccount(request)
   }

feature/registration/src/test/java/org/signal/registration/screens/aepentry/EnterAepForLocalBackupViewModelTest.kt

@@ -92,7 +92,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `Submit without requiring registration hands the key back and navigates back`() = runTest {
     val viewModel = createViewModel(isPreRegistration = false)
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
 
@@ -107,13 +107,13 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `Submit with a key that cannot decrypt the backup shows an inline error without registering`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.verifyLocalBackupKey(any(), any()) } returns false
 
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
 
-    assertThat(emittedStates.last().aepValidationError).isEqualTo(AepValidationError.Incorrect)
+    assertThat(emittedStates.last().recoveryKey.error).isEqualTo(AepValidationError.Incorrect)
     assertThat(emittedStates.last().isRegistering).isEqualTo(false)
     coVerify(exactly = 0) { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) }
   }
@@ -126,7 +126,7 @@ class EnterAepForLocalBackupViewModelTest {
       io.mockk.every { accountEntropyPool } returns aep
     }
     val mockResponse = mockk<RegisterAccountResponse>(relaxed = true)
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.verifyLocalBackupKey(any(), any()) } returns true
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
@@ -144,7 +144,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `Submit with RegistrationRecoveryPasswordIncorrect shows the different account dialog`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.verifyLocalBackupKey(any(), any()) } returns true
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
@@ -162,7 +162,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `ConfirmDifferentAccountRestore forces the session path and hands control back for SMS verification`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true, showDifferentAccountDialog = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP), showDifferentAccountDialog = true)
 
     viewModel.applyEvent(initialState, EnterAepEvents.ConfirmDifferentAccountRestore, stateEmitter)
 
@@ -176,7 +176,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `DismissDifferentAccountDialog clears the dialog`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true, showDifferentAccountDialog = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP), showDifferentAccountDialog = true)
 
     viewModel.applyEvent(initialState, EnterAepEvents.DismissDifferentAccountDialog, stateEmitter)
 
@@ -192,7 +192,7 @@ class EnterAepForLocalBackupViewModelTest {
       io.mockk.every { accountEntropyPool } returns aep
     }
     val mockResponse = mockk<RegisterAccountResponse>(relaxed = true)
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     val registrationLockData = RegistrationLockResponse(
       timeRemaining = 86400000L,
       svr2Credentials = SvrCredentials(username = "test-username", password = "test-password")
@@ -217,7 +217,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `Submit with RegistrationLock when already providing the reglock token navigates to PinEntryForRegistrationLock`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     val registrationLockData = RegistrationLockResponse(
       timeRemaining = 86400000L,
       svr2Credentials = SvrCredentials(username = "test-username", password = "test-password")
@@ -241,7 +241,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `Submit with RateLimited sets registrationError to RateLimited`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.verifyLocalBackupKey(any(), any()) } returns true
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
@@ -258,7 +258,7 @@ class EnterAepForLocalBackupViewModelTest {
   @Test
   fun `Submit with RetryableNetworkError sets registrationError to NetworkError`() = runTest {
     val viewModel = createViewModel()
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.verifyLocalBackupKey(any(), any()) } returns true
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns

feature/registration/src/test/java/org/signal/registration/screens/aepentry/EnterAepForRemoteBackupPostRegistrationViewModelTest.kt

@@ -55,14 +55,14 @@ class EnterAepForRemoteBackupPostRegistrationViewModelTest {
     viewModel.applyEvent(EnterAepState(), EnterAepEvents.BackupKeyChanged(VALID_AEP), stateEmitter)
 
     assertThat(emittedStates).hasSize(1)
-    assertThat(emittedStates.last().backupKey).isEqualTo(VALID_AEP)
+    assertThat(emittedStates.last().recoveryKey.normalized).isEqualTo(VALID_AEP)
   }
 
   // ==================== Submit Tests ====================
 
   @Test
   fun `Submit with verified key emits UserSuppliedAepSubmitted then NavigateToScreen with RemoteRestore`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     coEvery { mockRepository.verifyBackupKeyAssociatedWithAccount(any()) } returns RequestResult.Success(Unit)
 
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
@@ -81,7 +81,7 @@ class EnterAepForRemoteBackupPostRegistrationViewModelTest {
 
   @Test
   fun `Submit sets isRegistering true before verification then false`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     coEvery { mockRepository.verifyBackupKeyAssociatedWithAccount(any()) } returns RequestResult.Success(Unit)
 
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
@@ -92,32 +92,33 @@ class EnterAepForRemoteBackupPostRegistrationViewModelTest {
   }
 
   @Test
-  fun `Submit with incorrect key sets aepValidationError and does not navigate`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+  fun `Submit with incorrect key flags the recovery key and does not navigate`() = runTest {
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     coEvery { mockRepository.verifyBackupKeyAssociatedWithAccount(any()) } returns
       RequestResult.NonSuccess(NetworkController.VerifyBackupKeyError.IncorrectKey)
 
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
 
     assertThat(emittedParentEvents).isEmpty()
-    assertThat(emittedStates.last().aepValidationError).isEqualTo(AepValidationError.Incorrect)
+    assertThat(emittedStates.last().recoveryKey.error).isEqualTo(AepValidationError.Incorrect)
   }
 
   @Test
-  fun `Submit with no backup is treated as an incorrect key and does not navigate`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+  fun `Submit with no backup sets NoRemoteBackup rather than marking the key incorrect`() = runTest {
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     coEvery { mockRepository.verifyBackupKeyAssociatedWithAccount(any()) } returns
       RequestResult.NonSuccess(NetworkController.VerifyBackupKeyError.NoBackup)
 
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
 
     assertThat(emittedParentEvents).isEmpty()
-    assertThat(emittedStates.last().aepValidationError).isEqualTo(AepValidationError.Incorrect)
+    assertThat(emittedStates.last().registrationError).isEqualTo(RegistrationError.NoRemoteBackup)
+    assertThat(emittedStates.last().recoveryKey.error).isNull()
   }
 
   @Test
   fun `Submit with rate limited sets registrationError and does not navigate`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     coEvery { mockRepository.verifyBackupKeyAssociatedWithAccount(any()) } returns
       RequestResult.NonSuccess(NetworkController.VerifyBackupKeyError.RateLimited(30.seconds))
 
@@ -129,7 +130,7 @@ class EnterAepForRemoteBackupPostRegistrationViewModelTest {
 
   @Test
   fun `Submit with network error sets registrationError and does not navigate`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     coEvery { mockRepository.verifyBackupKeyAssociatedWithAccount(any()) } returns
       RequestResult.RetryableNetworkError(IOException("network"))
 

feature/registration/src/test/java/org/signal/registration/screens/aepentry/EnterAepForRemoteBackupPreRegistrationViewModelTest.kt

@@ -66,7 +66,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
     viewModel.applyEvent(initialState, EnterAepEvents.BackupKeyChanged(VALID_AEP), stateEmitter)
 
     assertThat(emittedStates).hasSize(1)
-    assertThat(emittedStates.last().backupKey).isEqualTo(VALID_AEP)
+    assertThat(emittedStates.last().recoveryKey.normalized).isEqualTo(VALID_AEP)
   }
 
   // ==================== Submit Success Tests ====================
@@ -78,7 +78,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
       io.mockk.every { accountEntropyPool } returns aep
     }
     val mockResponse = mockk<RegisterAccountResponse>(relaxed = true)
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.Success(RegisteredAccountData(mockResponse, mockKeyMaterial, testAci))
@@ -101,7 +101,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
       io.mockk.every { accountEntropyPool } returns aep
     }
     val mockResponse = mockk<RegisterAccountResponse>(relaxed = true)
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.Success(RegisteredAccountData(mockResponse, mockKeyMaterial, testAci))
@@ -116,8 +116,8 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
   // ==================== Submit Error Tests ====================
 
   @Test
-  fun `Submit with RegistrationRecoveryPasswordIncorrect sets registrationError and aepValidationError`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+  fun `Submit with RegistrationRecoveryPasswordIncorrect sets registrationError and flags the recovery key`() = runTest {
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.NonSuccess(
@@ -127,13 +127,13 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
     viewModel.applyEvent(initialState, EnterAepEvents.Submit, stateEmitter)
 
     assertThat(emittedStates.last().registrationError).isEqualTo(RegistrationError.IncorrectRecoveryPassword)
-    assertThat(emittedStates.last().aepValidationError).isEqualTo(AepValidationError.Incorrect)
+    assertThat(emittedStates.last().recoveryKey.error).isEqualTo(AepValidationError.Incorrect)
     assertThat(emittedStates.last().isRegistering).isEqualTo(false)
   }
 
   @Test
   fun `Submit with InvalidRequest sets registrationError to UnknownError`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.NonSuccess(
@@ -153,7 +153,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
       io.mockk.every { accountEntropyPool } returns aep
     }
     val mockResponse = mockk<RegisterAccountResponse>(relaxed = true)
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     val registrationLockData = RegistrationLockResponse(
       timeRemaining = 86400000L,
       svr2Credentials = SvrCredentials(username = "test-username", password = "test-password")
@@ -182,7 +182,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
 
   @Test
   fun `Submit with RegistrationLock when already providing the reglock token navigates to PinEntryForRegistrationLock`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
     val svrCredentials = SvrCredentials(username = "test-username", password = "test-password")
     val registrationLockData = RegistrationLockResponse(
       timeRemaining = 86400000L,
@@ -206,7 +206,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
 
   @Test
   fun `Submit with RateLimited sets registrationError to RateLimited`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.NonSuccess(
@@ -221,7 +221,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
 
   @Test(expected = IllegalStateException::class)
   fun `Submit with SessionNotFoundOrNotVerified throws IllegalStateException`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.NonSuccess(
@@ -233,7 +233,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
 
   @Test(expected = IllegalStateException::class)
   fun `Submit with DeviceTransferPossible throws IllegalStateException`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.NonSuccess(
@@ -245,7 +245,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
 
   @Test
   fun `Submit with RetryableNetworkError sets registrationError to NetworkError`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.RetryableNetworkError(java.io.IOException("Network error"))
@@ -258,7 +258,7 @@ class EnterAepForRemoteBackupPreRegistrationViewModelTest {
 
   @Test
   fun `Submit with ApplicationError sets registrationError to UnknownError`() = runTest {
-    val initialState = EnterAepState(backupKey = VALID_AEP, isBackupKeyValid = true)
+    val initialState = EnterAepState(recoveryKey = AepInput.from(VALID_AEP))
 
     coEvery { mockRepository.registerAccountWithRecoveryPassword(any(), any(), any(), any(), any(), any()) } returns
       RequestResult.ApplicationError(RuntimeException("Unexpected"))

feature/registration/src/test/java/org/signal/registration/screens/aepentry/EnterAepScreenEventHandlerTest.kt

@@ -18,7 +18,7 @@ class EnterAepScreenEventHandlerTest {
       EnterAepEvents.BackupKeyChanged("a0O#=b")
     )
 
-    assertThat(updated.enteredText).isEqualTo("a0O#=b")
-    assertThat(updated.backupKey).isEqualTo("a0oo0b")
+    assertThat(updated.recoveryKey.enteredText).isEqualTo("a0O#=b")
+    assertThat(updated.recoveryKey.normalized).isEqualTo("a0oo0b")
   }
 }

feature/registration/src/test/java/org/signal/registration/screens/aepentry/EnterAepScreenTest.kt

@@ -101,8 +101,7 @@ class EnterAepScreenTest {
       SignalTheme {
         EnterAepScreen(
           state = EnterAepState(
-            isBackupKeyValid = true,
-            aepValidationError = null,
+            recoveryKey = AepInput(isValid = true),
             isRegistering = false
           ),
           onEvent = { event ->

feature/registration/src/test/java/org/signal/registration/screens/localbackuprestore/LocalBackupRestoreViewModelTest.kt

@@ -21,6 +21,7 @@ import io.mockk.every
 import io.mockk.mockk
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.UnconfinedTestDispatcher
@@ -80,7 +81,7 @@ class LocalBackupRestoreViewModelTest {
   ): LocalBackupRestoreViewModel {
     return LocalBackupRestoreViewModel(
       repository = mockRepository,
-      parentState = flowOf(parentState),
+      parentState = MutableStateFlow(parentState),
       parentEventEmitter = parentEventEmitter,
       isPreRegistration = isPreRegistration,
       resultBus = resultBus,
@@ -401,6 +402,28 @@ class LocalBackupRestoreViewModelTest {
     assertThat(emittedParentEvents).contains(RegistrationFlowEvent.RegistrationComplete)
   }
 
+  @Test
+  fun `restore without a PIN for a phone-numberless account completes registration, since it has no PIN`() = runTest(testDispatcher) {
+    val viewModel = createViewModel(
+      isPreRegistration = false,
+      parentState = RegistrationFlowState(storageCapable = true, isPhoneNumberlessAccount = true)
+    )
+    val backupInfo = LocalBackupInfo(
+      type = LocalBackupInfo.BackupType.V1,
+      date = LocalDateTime.now(),
+      name = "backup.backup",
+      uri = mockk()
+    )
+    val initialState = LocalBackupRestoreState(backupInfo = backupInfo, selectedFolderUri = mockk())
+
+    every { mockRepository.restoreV1Backup(any(), any(), any()) } returns flowOf(LocalBackupRestoreProgress.Complete(restoredSvrPin = null, restoredProfileKey = null))
+
+    viewModel.applyEvent(initialState, LocalBackupRestoreEvents.PassphraseSubmitted("passphrase"), stateEmitter)
+
+    coVerify { mockRepository.restoreAccountRecord(any()) }
+    assertThat(emittedParentEvents).contains(RegistrationFlowEvent.RegistrationComplete)
+  }
+
   @Test
   fun `V1 restore without a PIN when storage capable navigates to PinEntryForSvrRestore`() = runTest(testDispatcher) {
     val viewModel = createViewModel(isPreRegistration = false, storageCapable = true)

feature/registration/src/test/java/org/signal/registration/screens/pinentry/PinEntryForRegistrationLockViewModelTest.kt

@@ -125,7 +125,7 @@ class PinEntryForRegistrationLockViewModelTest {
       .isInstanceOf<RegistrationFlowEvent.NavigateToScreen>()
       .prop(RegistrationFlowEvent.NavigateToScreen::route)
       .isEqualTo(RegistrationRoute.ArchiveRestoreSelection.forPostRegisterWithPinKnown())
-    coVerify { mockRepository.restoreAccountRecord(any()) }
+    coVerify(exactly = 0) { mockRepository.restoreAccountRecord(any()) }
     assertThat(emittedStates.last().loading).isEqualTo(true)
   }
 

feature/registration/src/test/java/org/signal/registration/screens/remotebackuprestore/RemoteBackupRestoreViewModelTest.kt

@@ -6,6 +6,8 @@
 package org.signal.registration.screens.remotebackuprestore
 
 import assertk.assertThat
+import assertk.assertions.containsExactly
+import assertk.assertions.doesNotContain
 import assertk.assertions.hasSize
 import assertk.assertions.isEqualTo
 import assertk.assertions.isNull
@@ -70,11 +72,16 @@ class RemoteBackupRestoreViewModelTest {
     Dispatchers.resetMain()
   }
 
-  private fun createViewModel(storageCapable: Boolean = false): RemoteBackupRestoreViewModel {
+  private fun createViewModel(
+    storageCapable: Boolean = false,
+    phoneNumberless: Boolean = false,
+    canNavigateBackwards: Boolean = false
+  ): RemoteBackupRestoreViewModel {
     return RemoteBackupRestoreViewModel(
       aep = aep,
+      canNavigateBackwards = canNavigateBackwards,
       repository = mockRepository,
-      parentState = MutableStateFlow(RegistrationFlowState(storageCapable = storageCapable)),
+      parentState = MutableStateFlow(RegistrationFlowState(storageCapable = storageCapable, isPhoneNumberlessAccount = phoneNumberless)),
       parentEventEmitter = parentEventEmitter,
       ioDispatcher = testDispatcher
     )
@@ -116,14 +123,88 @@ class RemoteBackupRestoreViewModelTest {
   // ==================== Cancel ====================
 
   @Test
-  fun `Cancel emits NavigateBack`() = runTest(testDispatcher) {
+  fun `Cancel records the skip and completes registration when a pin is known`() = runTest(testDispatcher) {
+    coEvery { mockRepository.hasKnownPin() } returns true
     val viewModel = createViewModel()
-    val initialState = RemoteBackupRestoreState(aep = aep)
 
-    viewModel.applyEvent(initialState, RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
 
-    assertThat(emittedParentEvents).hasSize(1)
-    assertThat(emittedParentEvents.first()).isEqualTo(RegistrationFlowEvent.NavigateBack)
+    coVerify { mockRepository.setRestoreDecision(RestoreDecision.SKIPPED) }
+    coVerify { mockRepository.restoreAccountRecord() }
+    assertThat(emittedParentEvents.last()).isEqualTo(RegistrationFlowEvent.RegistrationComplete)
+  }
+
+  @Test
+  fun `Cancel navigates to pin creation when no pin is known and the account is not storage capable`() = runTest(testDispatcher) {
+    coEvery { mockRepository.hasKnownPin() } returns false
+    val viewModel = createViewModel(storageCapable = false)
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+
+    coVerify { mockRepository.setRestoreDecision(RestoreDecision.SKIPPED) }
+    assertThat(emittedParentEvents.last()).isEqualTo(RegistrationFlowEvent.NavigateToScreen(RegistrationRoute.PinCreate))
+  }
+
+  @Test
+  fun `Cancel navigates to SVR pin entry when no pin is known and the account is storage capable`() = runTest(testDispatcher) {
+    coEvery { mockRepository.hasKnownPin() } returns false
+    val viewModel = createViewModel(storageCapable = true)
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+
+    coVerify { mockRepository.setRestoreDecision(RestoreDecision.SKIPPED) }
+    assertThat(emittedParentEvents.last()).isEqualTo(RegistrationFlowEvent.NavigateToScreen(RegistrationRoute.PinEntryForSvrRestore))
+  }
+
+  @Test
+  fun `Cancel completes registration for a phone-numberless account, which has no pin`() = runTest(testDispatcher) {
+    coEvery { mockRepository.hasKnownPin() } returns false
+    val viewModel = createViewModel(storageCapable = true, phoneNumberless = true)
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+
+    coVerify { mockRepository.setRestoreDecision(RestoreDecision.SKIPPED) }
+    coVerify { mockRepository.restoreAccountRecord() }
+    assertThat(emittedParentEvents.last()).isEqualTo(RegistrationFlowEvent.RegistrationComplete)
+  }
+
+  @Test
+  fun `Complete progress completes registration for a phone-numberless account, which has no pin`() = runTest(testDispatcher) {
+    coEvery { mockRepository.hasKnownPin() } returns false
+    every { mockRepository.restoreRemoteBackup(any()) } returns flowOf(RemoteBackupRestoreProgress.Complete(restoredSvrPin = null, restoredProfileKey = null))
+    val viewModel = createViewModel(storageCapable = true, phoneNumberless = true)
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.BackupRestoreBackup, stateEmitter)
+
+    assertThat(emittedParentEvents.last()).isEqualTo(RegistrationFlowEvent.RegistrationComplete)
+  }
+
+  @Test
+  fun `Cancel never navigates back, since this screen cleared the back stack`() = runTest(testDispatcher) {
+    val viewModel = createViewModel()
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+
+    assertThat(emittedParentEvents).doesNotContain(RegistrationFlowEvent.NavigateBack)
+  }
+
+  @Test
+  fun `Cancel navigates back to the restore selection screen when it is still behind us`() = runTest(testDispatcher) {
+    val viewModel = createViewModel(canNavigateBackwards = true)
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+
+    assertThat(emittedParentEvents).containsExactly(RegistrationFlowEvent.NavigateBack)
+  }
+
+  @Test
+  fun `Cancel does not record a skip when handing control back to the restore selection screen`() = runTest(testDispatcher) {
+    val viewModel = createViewModel(canNavigateBackwards = true)
+
+    viewModel.applyEvent(RemoteBackupRestoreState(aep = aep), RemoteBackupRestoreScreenEvents.Cancel, stateEmitter)
+
+    coVerify(exactly = 0) { mockRepository.setRestoreDecision(any()) }
+    assertThat(emittedParentEvents).doesNotContain(RegistrationFlowEvent.RegistrationComplete)
   }
 
   // ==================== Retry ====================

feature/registration/src/test/java/org/signal/registration/screens/restoreselection/ArchiveRestoreSelectionViewModelTest.kt

@@ -225,13 +225,14 @@ class ArchiveRestoreSelectionViewModelTest {
   }
 
   @Test
-  fun `ConfirmSkip post-registration when PIN is known records skip and completes registration`() = runTest {
+  fun `ConfirmSkip post-registration when PIN is known records skip, restores the account record, and completes registration`() = runTest {
     val viewModel = createViewModel(registeredState = RegisteredState.RegisteredAndPinKnown)
     val initialState = ArchiveRestoreSelectionState(showSkipWarningDialog = true)
 
     viewModel.applyEvent(initialState, ArchiveRestoreSelectionScreenEvents.ConfirmSkip, stateEmitter)
 
     coVerify { mockRepository.setRestoreDecision(RestoreDecision.SKIPPED) }
+    coVerify { mockRepository.restoreAccountRecord() }
     assertThat(emittedParentEvents).hasSize(1)
     assertThat(emittedParentEvents.first()).isEqualTo(RegistrationFlowEvent.RegistrationComplete)
     assertThat(emittedStates.last().showSkipWarningDialog).isFalse()

feature/registration/src/test/java/org/signal/registration/screens/signallogin/SignalLoginScreenTest.kt

@@ -1,101 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-import android.app.Application
-import androidx.compose.ui.test.assertIsEnabled
-import androidx.compose.ui.test.assertIsNotEnabled
-import androidx.compose.ui.test.junit4.createComposeRule
-import androidx.compose.ui.test.onNodeWithTag
-import androidx.compose.ui.test.performClick
-import androidx.compose.ui.test.performTextInput
-import androidx.test.core.app.ApplicationProvider
-import assertk.assertThat
-import assertk.assertions.contains
-import org.junit.Rule
-import org.junit.Test
-import org.junit.runner.RunWith
-import org.robolectric.RobolectricTestRunner
-import org.robolectric.annotation.Config
-import org.signal.core.ui.CoreUiDependenciesRule
-import org.signal.core.ui.compose.theme.SignalTheme
-import org.signal.registration.test.TestTags
-
-@RunWith(RobolectricTestRunner::class)
-@Config(application = Application::class)
-class SignalLoginScreenTest {
-
-  companion object {
-    private const val VALID_ACCOUNT_KEY = "a6b284822e3283d07f2391360a4c2b91"
-  }
-
-  @get:Rule
-  val composeTestRule = createComposeRule()
-
-  @get:Rule
-  val coreUiDependenciesRule = CoreUiDependenciesRule(ApplicationProvider.getApplicationContext())
-
-  private val events = mutableListOf<SignalLoginScreenEvents>()
-
-  @Test
-  fun `when text is typed into the account key field, AccountKeyChanged is emitted`() {
-    setContent(SignalLoginState())
-
-    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_ACCOUNT_KEY_FIELD).performTextInput("a6b2")
-
-    assertThat(events).contains(SignalLoginScreenEvents.AccountKeyChanged("a6b2"))
-  }
-
-  @Test
-  fun `when Need help is clicked, NeedHelpClicked is emitted`() {
-    setContent(SignalLoginState())
-
-    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_NEED_HELP_BUTTON).performClick()
-
-    assertThat(events).contains(SignalLoginScreenEvents.NeedHelpClicked)
-  }
-
-  @Test
-  fun `when Next is clicked with a complete key, NextClicked is emitted`() {
-    setContent(SignalLoginState(accountKey = VALID_ACCOUNT_KEY))
-
-    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_NEXT_BUTTON).performClick()
-
-    assertThat(events).contains(SignalLoginScreenEvents.NextClicked)
-  }
-
-  @Test
-  fun `given an incomplete key, Next is disabled`() {
-    setContent(SignalLoginState(accountKey = "a6b28482"))
-
-    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_NEXT_BUTTON).assertIsNotEnabled()
-  }
-
-  @Test
-  fun `given a complete key, Next is enabled`() {
-    setContent(SignalLoginState(accountKey = VALID_ACCOUNT_KEY))
-
-    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_NEXT_BUTTON).assertIsEnabled()
-  }
-
-  @Test
-  fun `given a submission is in flight, Next is disabled`() {
-    setContent(SignalLoginState(accountKey = VALID_ACCOUNT_KEY, isSubmitting = true))
-
-    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_NEXT_BUTTON).assertIsNotEnabled()
-  }
-
-  private fun setContent(state: SignalLoginState) {
-    composeTestRule.setContent {
-      SignalTheme {
-        SignalLoginScreen(
-          state = state,
-          onEvent = { events += it }
-        )
-      }
-    }
-  }
-}

feature/registration/src/test/java/org/signal/registration/screens/signallogin/SignalLoginViewModelTest.kt

@@ -1,148 +0,0 @@
-/*
- * Copyright 2026 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.signal.registration.screens.signallogin
-
-import assertk.assertThat
-import assertk.assertions.containsExactly
-import assertk.assertions.isEmpty
-import assertk.assertions.isEqualTo
-import assertk.assertions.isFalse
-import assertk.assertions.isNull
-import assertk.assertions.isTrue
-import io.mockk.mockk
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.flow.toList
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.test.UnconfinedTestDispatcher
-import kotlinx.coroutines.test.resetMain
-import kotlinx.coroutines.test.runTest
-import kotlinx.coroutines.test.setMain
-import org.junit.After
-import org.junit.Before
-import org.junit.Test
-import org.signal.registration.RegistrationFlowEvent
-import org.signal.registration.RegistrationRepository
-
-@OptIn(ExperimentalCoroutinesApi::class)
-class SignalLoginViewModelTest {
-
-  companion object {
-    private const val VALID_ACCOUNT_KEY = "a6b284822e3283d07f2391360a4c2b91"
-  }
-
-  private val testDispatcher = UnconfinedTestDispatcher()
-
-  private lateinit var mockRepository: RegistrationRepository
-  private lateinit var viewModel: SignalLoginViewModel
-
-  @Before
-  fun setup() {
-    Dispatchers.setMain(testDispatcher)
-    mockRepository = mockk(relaxed = true)
-    viewModel = SignalLoginViewModel(repository = mockRepository, parentEventEmitter = {})
-  }
-
-  @After
-  fun tearDown() {
-    Dispatchers.resetMain()
-  }
-
-  @Test
-  fun `BackClicked navigates back`() = runTest(testDispatcher) {
-    val parentEvents = mutableListOf<RegistrationFlowEvent>()
-
-    viewModel.applyEvent(SignalLoginState(), SignalLoginScreenEvents.BackClicked, { parentEvents.add(it) }) {}
-
-    assertThat(parentEvents).containsExactly(RegistrationFlowEvent.NavigateBack)
-  }
-
-  @Test
-  fun `AccountKeyChanged strips formatting and lowercases the entered key`() = runTest(testDispatcher) {
-    val state = applyAccountKey("A6B28482-2E32-83D0-7F23 91360A4C2B91")
-
-    assertThat(state.accountKey).isEqualTo(VALID_ACCOUNT_KEY)
-    assertThat(state.accountKeyError).isNull()
-    assertThat(state.isNextEnabled).isTrue()
-  }
-
-  @Test
-  fun `AccountKeyChanged does not report an error for a partially typed key`() = runTest(testDispatcher) {
-    val state = applyAccountKey("a6b28482")
-
-    assertThat(state.accountKeyError).isNull()
-    assertThat(state.isNextEnabled).isFalse()
-  }
-
-  @Test
-  fun `AccountKeyChanged reports non-hex characters as invalid`() = runTest(testDispatcher) {
-    val state = applyAccountKey(VALID_ACCOUNT_KEY.dropLast(1) + "z")
-
-    assertThat(state.accountKeyError).isEqualTo(AccountKeyError.Invalid)
-    assertThat(state.isNextEnabled).isFalse()
-  }
-
-  @Test
-  fun `AccountKeyChanged reports an over-long key as too long`() = runTest(testDispatcher) {
-    val state = applyAccountKey(VALID_ACCOUNT_KEY + "ab")
-
-    assertThat(state.accountKeyError).isEqualTo(AccountKeyError.TooLong(34))
-    assertThat(state.isNextEnabled).isFalse()
-  }
-
-  @Test
-  fun `NeedHelpClicked opens the help article`() = runTest(testDispatcher) {
-    val actions = mutableListOf<SignalLoginScreenActions>()
-    backgroundScope.launch { viewModel.actions.toList(actions) }
-
-    viewModel.applyEvent(SignalLoginState(), SignalLoginScreenEvents.NeedHelpClicked, {}) {}
-
-    assertThat(actions).containsExactly(SignalLoginScreenActions.OpenNeedHelpArticle)
-  }
-
-  @Test
-  fun `NextClicked does nothing yet because logging in is not implemented`() = runTest(testDispatcher) {
-    val parentEvents = mutableListOf<RegistrationFlowEvent>()
-    val states = mutableListOf<SignalLoginState>()
-
-    viewModel.applyEvent(SignalLoginState(accountKey = VALID_ACCOUNT_KEY), SignalLoginScreenEvents.NextClicked, { parentEvents.add(it) }) { states.add(it) }
-
-    assertThat(parentEvents).isEmpty()
-    assertThat(states).isEmpty()
-  }
-
-  @Test
-  fun `NetworkErrorDialogDismissed clears the dialog`() = runTest(testDispatcher) {
-    var state: SignalLoginState? = null
-
-    viewModel.applyEvent(
-      SignalLoginState(dialogs = SignalLoginState.Dialogs(networkError = true)),
-      SignalLoginScreenEvents.NetworkErrorDialogDismissed,
-      {}
-    ) { state = it }
-
-    assertThat(state!!.dialogs.networkError).isFalse()
-  }
-
-  @Test
-  fun `UnknownErrorDialogDismissed clears the dialog`() = runTest(testDispatcher) {
-    var state: SignalLoginState? = null
-
-    viewModel.applyEvent(
-      SignalLoginState(dialogs = SignalLoginState.Dialogs(unknownError = true)),
-      SignalLoginScreenEvents.UnknownErrorDialogDismissed,
-      {}
-    ) { state = it }
-
-    assertThat(state!!.dialogs.unknownError).isFalse()
-  }
-
-  private suspend fun applyAccountKey(value: String): SignalLoginState {
-    var state = SignalLoginState()
-    viewModel.applyEvent(state, SignalLoginScreenEvents.AccountKeyChanged(value), {}) { state = it }
-    return state
-  }
-}

feature/registration/src/test/java/org/signal/registration/screens/signallogincredentials/AccountIdVisualTransformationTest.kt

@@ -3,14 +3,14 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-package org.signal.registration.screens.signallogin
+package org.signal.registration.screens.signallogincredentials
 
 import androidx.compose.ui.text.AnnotatedString
 import assertk.assertThat
 import assertk.assertions.isEqualTo
 import org.junit.Test
 
-class AccountKeyVisualTransformationTest {
+class AccountIdVisualTransformationTest {
 
   companion object {
     private const val FULL_KEY = "a6b284822e3283d07f2391360a4c2b91"
@@ -42,7 +42,7 @@ class AccountKeyVisualTransformationTest {
   fun `every cursor position maps into the transformed text and back`() {
     for (length in 0..FULL_KEY.length) {
       val key = FULL_KEY.take(length)
-      val mapping = AccountKeyVisualTransformation.filter(AnnotatedString(key)).offsetMapping
+      val mapping = AccountIdVisualTransformation.filter(AnnotatedString(key)).offsetMapping
       val transformedLength = transform(key).length
 
       for (offset in 0..length) {
@@ -54,5 +54,5 @@ class AccountKeyVisualTransformationTest {
     }
   }
 
-  private fun transform(text: String): String = AccountKeyVisualTransformation.filter(AnnotatedString(text)).text.text
+  private fun transform(text: String): String = AccountIdVisualTransformation.filter(AnnotatedString(text)).text.text
 }

feature/registration/src/test/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenTest.kt

@@ -0,0 +1,150 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import android.app.Application
+import androidx.compose.ui.test.assertIsEnabled
+import androidx.compose.ui.test.assertIsNotEnabled
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithTag
+import androidx.compose.ui.test.performClick
+import androidx.compose.ui.test.performScrollTo
+import androidx.compose.ui.test.performTextInput
+import androidx.test.core.app.ApplicationProvider
+import assertk.assertThat
+import assertk.assertions.contains
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.signal.core.ui.CoreUiDependenciesRule
+import org.signal.core.ui.compose.theme.SignalTheme
+import org.signal.registration.screens.aepentry.AepInput
+import org.signal.registration.test.TestTags
+
+@RunWith(RobolectricTestRunner::class)
+@Config(application = Application::class)
+class SignalLoginCredentialEntryScreenTest {
+
+  companion object {
+    private const val VALID_ACCOUNT_ID = "a6b284822e3283d07f2391360a4c2b91"
+    private const val VALID_RECOVERY_KEY = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"
+  }
+
+  @get:Rule
+  val composeTestRule = createComposeRule()
+
+  @get:Rule
+  val coreUiDependenciesRule = CoreUiDependenciesRule(ApplicationProvider.getApplicationContext())
+
+  private val events = mutableListOf<SignalLoginCredentialEntryScreenEvents>()
+
+  @Test
+  fun `when text is typed into the account ID field, AccountIdChanged is emitted`() {
+    setContent(SignalLoginCredentialEntryState())
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_ACCOUNT_ID_FIELD).performTextInput("a6b2")
+
+    assertThat(events).contains(SignalLoginCredentialEntryScreenEvents.AccountIdChanged("a6b2"))
+  }
+
+  @Test
+  fun `when text is typed into the recovery key field, RecoveryKeyChanged is emitted`() {
+    setContent(SignalLoginCredentialEntryState())
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_RECOVERY_KEY_FIELD).performTextInput("uy38")
+
+    assertThat(events).contains(SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged("uy38"))
+  }
+
+  @Test
+  fun `when the eye button is clicked, RecoveryKeyVisibilityToggled is emitted`() {
+    setContent(SignalLoginCredentialEntryState())
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_REVEAL_RECOVERY_KEY_BUTTON, useUnmergedTree = true).performScrollTo().performClick()
+
+    assertThat(events).contains(SignalLoginCredentialEntryScreenEvents.RecoveryKeyVisibilityToggled)
+  }
+
+  @Test
+  fun `when Need help is clicked, NeedHelpClicked is emitted`() {
+    setContent(SignalLoginCredentialEntryState())
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEED_HELP_BUTTON).performClick()
+
+    assertThat(events).contains(SignalLoginCredentialEntryScreenEvents.NeedHelpClicked)
+  }
+
+  @Test
+  fun `when Next is clicked with a complete login, NextClicked is emitted`() {
+    setContent(completeState())
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).performClick()
+
+    assertThat(events).contains(SignalLoginCredentialEntryScreenEvents.NextClicked)
+  }
+
+  @Test
+  fun `given a complete login, Next is enabled`() {
+    setContent(completeState())
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).assertIsEnabled()
+  }
+
+  @Test
+  fun `given an incomplete account ID, Next is disabled`() {
+    setContent(completeState().copy(accountId = "a6b28482"))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).assertIsNotEnabled()
+  }
+
+  @Test
+  fun `given an incomplete recovery key, Next is disabled`() {
+    setContent(completeState().copy(recoveryKey = AepInput.from("uy38jh27")))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).assertIsNotEnabled()
+  }
+
+  @Test
+  fun `given an account ID with an invalid character, Next is disabled`() {
+    setContent(completeState().copy(accountIdError = AccountIdError.Invalid))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).assertIsNotEnabled()
+  }
+
+  @Test
+  fun `given a rejected login, Next stays disabled until something is edited`() {
+    setContent(completeState().copy(areCredentialsIncorrect = true))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).assertIsNotEnabled()
+  }
+
+  @Test
+  fun `while logging in, Next is disabled`() {
+    setContent(completeState().copy(isLoggingIn = true))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_NEXT_BUTTON).assertIsNotEnabled()
+  }
+
+  private fun completeState(): SignalLoginCredentialEntryState {
+    return SignalLoginCredentialEntryState(
+      accountId = VALID_ACCOUNT_ID,
+      recoveryKey = AepInput.from(VALID_RECOVERY_KEY)
+    )
+  }
+
+  private fun setContent(state: SignalLoginCredentialEntryState) {
+    composeTestRule.setContent {
+      SignalTheme {
+        SignalLoginCredentialEntryScreen(
+          state = state,
+          onEvent = { events += it }
+        )
+      }
+    }
+  }
+}

feature/registration/src/test/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryViewModelTest.kt

@@ -0,0 +1,414 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.signal.registration.screens.signallogincredentials
+
+import assertk.assertThat
+import assertk.assertions.containsExactly
+import assertk.assertions.hasSize
+import assertk.assertions.isEmpty
+import assertk.assertions.isEqualTo
+import assertk.assertions.isFalse
+import assertk.assertions.isInstanceOf
+import assertk.assertions.isNotNull
+import assertk.assertions.isNull
+import assertk.assertions.isTrue
+import assertk.assertions.prop
+import io.mockk.coEvery
+import io.mockk.coVerify
+import io.mockk.every
+import io.mockk.mockk
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.toList
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+import org.signal.core.models.AccountEntropyPool
+import org.signal.core.models.ServiceId.ACI
+import org.signal.libsignal.net.RequestResult
+import org.signal.network.api.RegistrationApiV2.RegisterAccountError
+import org.signal.network.api.RegistrationApiV2.RegisterAccountResponse
+import org.signal.network.api.RegistrationApiV2.RegistrationLockResponse
+import org.signal.network.api.RegistrationApiV2.SvrCredentials
+import org.signal.registration.KeyMaterial
+import org.signal.registration.NetworkController
+import org.signal.registration.RegisteredAccountData
+import org.signal.registration.RegistrationFlowEvent
+import org.signal.registration.RegistrationRepository
+import org.signal.registration.RegistrationRoute
+import org.signal.registration.RestoreDecision
+import org.signal.registration.screens.aepentry.AepInput
+import org.signal.registration.screens.restoreselection.ArchiveRestoreOption
+import org.signal.registration.screens.restoreselection.RegisteredState
+import java.io.IOException
+import java.util.UUID
+import kotlin.time.Duration
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class SignalLoginCredentialEntryViewModelTest {
+
+  companion object {
+    private const val VALID_ACCOUNT_ID = "a6b284822e3283d07f2391360a4c2b91"
+    private const val VALID_AEP = "uy38jh2778hjjhj8lk19ga61s672jsj089r023s6a57809bap92j2yh5t326vv7t"
+    private val VALID_ACI = ACI.from(UUID.fromString("a6b28482-2e32-83d0-7f23-91360a4c2b91"))
+  }
+
+  private val testDispatcher = UnconfinedTestDispatcher()
+
+  private lateinit var viewModel: SignalLoginCredentialEntryViewModel
+  private lateinit var mockRepository: RegistrationRepository
+  private lateinit var emittedParentEvents: MutableList<RegistrationFlowEvent>
+  private lateinit var emittedStates: MutableList<SignalLoginCredentialEntryState>
+  private lateinit var parentEventEmitter: (RegistrationFlowEvent) -> Unit
+  private lateinit var stateEmitter: (SignalLoginCredentialEntryState) -> Unit
+
+  @Before
+  fun setup() {
+    Dispatchers.setMain(testDispatcher)
+    mockRepository = mockk(relaxed = true)
+    emittedParentEvents = mutableListOf()
+    emittedStates = mutableListOf()
+    parentEventEmitter = { event -> emittedParentEvents.add(event) }
+    stateEmitter = { state -> emittedStates.add(state) }
+    viewModel = SignalLoginCredentialEntryViewModel(repository = mockRepository, parentEventEmitter = parentEventEmitter)
+  }
+
+  @After
+  fun tearDown() {
+    Dispatchers.resetMain()
+  }
+
+  @Test
+  fun `BackClicked navigates back`() = runTest(testDispatcher) {
+    applyEvent(SignalLoginCredentialEntryState(), SignalLoginCredentialEntryScreenEvents.BackClicked)
+
+    assertThat(emittedParentEvents).containsExactly(RegistrationFlowEvent.NavigateBack)
+  }
+
+  @Test
+  fun `AccountIdChanged strips formatting and lowercases the entered ID`() = runTest(testDispatcher) {
+    val state = applyAccountId("A6B28482-2E32-83D0-7F23 91360A4C2B91")
+
+    assertThat(state.accountId).isEqualTo(VALID_ACCOUNT_ID)
+    assertThat(state.accountIdError).isNull()
+  }
+
+  @Test
+  fun `AccountIdChanged does not report an error for a partially typed ID`() = runTest(testDispatcher) {
+    val state = applyAccountId("a6b28482")
+
+    assertThat(state.accountIdError).isNull()
+    assertThat(state.isNextEnabled).isFalse()
+  }
+
+  @Test
+  fun `AccountIdChanged reports non-hex characters as invalid`() = runTest(testDispatcher) {
+    val state = applyAccountId(VALID_ACCOUNT_ID.dropLast(1) + "z")
+
+    assertThat(state.accountIdError).isEqualTo(AccountIdError.Invalid)
+    assertThat(state.isNextEnabled).isFalse()
+  }
+
+  @Test
+  fun `AccountIdChanged reports an over-long ID as too long`() = runTest(testDispatcher) {
+    val state = applyAccountId(VALID_ACCOUNT_ID + "ab")
+
+    assertThat(state.accountIdError).isEqualTo(AccountIdError.TooLong(34))
+    assertThat(state.isNextEnabled).isFalse()
+  }
+
+  @Test
+  fun `RecoveryKeyChanged normalizes the entered key`() = runTest(testDispatcher) {
+    applyEvent(SignalLoginCredentialEntryState(), SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged(VALID_AEP.uppercase()))
+
+    assertThat(emittedStates.last().recoveryKey.normalized).isEqualTo(VALID_AEP)
+    assertThat(emittedStates.last().recoveryKey.isValid).isTrue()
+  }
+
+  @Test
+  fun `editing either half clears a rejected login`() = runTest(testDispatcher) {
+    val rejected = completeState().copy(areCredentialsIncorrect = true)
+
+    applyEvent(rejected, SignalLoginCredentialEntryScreenEvents.AccountIdChanged(VALID_ACCOUNT_ID.dropLast(1)))
+    assertThat(emittedStates.last().areCredentialsIncorrect).isFalse()
+
+    applyEvent(rejected, SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged(VALID_AEP.dropLast(1)))
+    assertThat(emittedStates.last().areCredentialsIncorrect).isFalse()
+  }
+
+  @Test
+  fun `RecoveryKeyVisibilityToggled flips whether the key is spelled out`() = runTest(testDispatcher) {
+    applyEvent(SignalLoginCredentialEntryState(), SignalLoginCredentialEntryScreenEvents.RecoveryKeyVisibilityToggled)
+
+    assertThat(emittedStates.last().isRecoveryKeyRevealed).isTrue()
+  }
+
+  @Test
+  fun `NeedHelpClicked opens the help article`() = runTest(testDispatcher) {
+    val actions = mutableListOf<SignalLoginCredentialEntryScreenActions>()
+    backgroundScope.launch { viewModel.actions.toList(actions) }
+
+    applyEvent(SignalLoginCredentialEntryState(), SignalLoginCredentialEntryScreenEvents.NeedHelpClicked)
+
+    assertThat(actions).containsExactly(SignalLoginCredentialEntryScreenActions.OpenNeedHelpArticle)
+  }
+
+  @Test
+  fun `DismissError clears the login error`() = runTest(testDispatcher) {
+    applyEvent(completeState().copy(loginError = SignalLoginError.NetworkError), SignalLoginCredentialEntryScreenEvents.DismissError)
+
+    assertThat(emittedStates.last().loginError).isNull()
+  }
+
+  @Test
+  fun `NextClicked with an account ID that is not a valid ACI reports it as invalid`() = runTest(testDispatcher) {
+    applyEvent(completeState().copy(accountId = "a6b28482"), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedParentEvents).isEmpty()
+    assertThat(emittedStates.last().accountIdError).isEqualTo(AccountIdError.Invalid)
+  }
+
+  @Test
+  fun `NextClicked logs in with the entered account ID and the recovery password derived from the entered key`() = runTest(testDispatcher) {
+    val aep = AccountEntropyPool(VALID_AEP)
+    stubSuccessfulLogin(aep)
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    coVerify {
+      mockRepository.reRegisterAccountWithoutPhoneNumber(
+        aci = VALID_ACI,
+        recoveryPassword = aep.deriveMasterKey().deriveRegistrationRecoveryPassword(),
+        aep = match { it.value == VALID_AEP },
+        registrationLock = null
+      )
+    }
+  }
+
+  @Test
+  fun `NextClicked reclaiming an existing account emits UserSuppliedAepSubmitted, Registered, and navigates to the restore selection`() = runTest(testDispatcher) {
+    val aep = AccountEntropyPool(VALID_AEP)
+    stubSuccessfulLogin(aep, reregistration = true)
+    stubRemoteBackup(exists = true)
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedParentEvents).hasSize(3)
+    assertThat(emittedParentEvents[0]).isInstanceOf<RegistrationFlowEvent.UserSuppliedAepSubmitted>()
+    assertThat(emittedParentEvents[1])
+      .isInstanceOf<RegistrationFlowEvent.Registered>()
+      .prop(RegistrationFlowEvent.Registered::phoneNumberless)
+      .isEqualTo(true)
+
+    val route = assertThat(emittedParentEvents[2])
+      .isInstanceOf<RegistrationFlowEvent.NavigateToScreen>()
+      .prop(RegistrationFlowEvent.NavigateToScreen::route)
+      .isInstanceOf<RegistrationRoute.ArchiveRestoreSelection>()
+
+    route.prop(RegistrationRoute.ArchiveRestoreSelection::aep).isNotNull().prop(AccountEntropyPool::value).isEqualTo(aep.value)
+    route.prop(RegistrationRoute.ArchiveRestoreSelection::registeredState).isEqualTo(RegisteredState.RegisteredAndPinKnown)
+    route.prop(RegistrationRoute.ArchiveRestoreSelection::restoreOptions)
+      .containsExactly(ArchiveRestoreOption.SignalSecureBackup, ArchiveRestoreOption.LocalBackup, ArchiveRestoreOption.None)
+  }
+
+  @Test
+  fun `NextClicked reclaiming an account with no remote backup does not offer a remote restore`() = runTest(testDispatcher) {
+    stubSuccessfulLogin(AccountEntropyPool(VALID_AEP), reregistration = true)
+    stubRemoteBackup(exists = false)
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedParentEvents.last())
+      .isInstanceOf<RegistrationFlowEvent.NavigateToScreen>()
+      .prop(RegistrationFlowEvent.NavigateToScreen::route)
+      .isInstanceOf<RegistrationRoute.ArchiveRestoreSelection>()
+      .prop(RegistrationRoute.ArchiveRestoreSelection::restoreOptions)
+      .containsExactly(ArchiveRestoreOption.LocalBackup, ArchiveRestoreOption.None)
+  }
+
+  @Test
+  fun `NextClicked reclaiming an account still offers a remote restore when the backup check fails`() = runTest(testDispatcher) {
+    stubSuccessfulLogin(AccountEntropyPool(VALID_AEP), reregistration = true)
+    coEvery { mockRepository.getAndMaybeHealRemoteBackupInfo(any()) } returns RequestResult.RetryableNetworkError(IOException("Network error"))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedParentEvents.last())
+      .isInstanceOf<RegistrationFlowEvent.NavigateToScreen>()
+      .prop(RegistrationFlowEvent.NavigateToScreen::route)
+      .isInstanceOf<RegistrationRoute.ArchiveRestoreSelection>()
+      .prop(RegistrationRoute.ArchiveRestoreSelection::restoreOptions)
+      .containsExactly(ArchiveRestoreOption.SignalSecureBackup, ArchiveRestoreOption.LocalBackup, ArchiveRestoreOption.None)
+  }
+
+  @Test
+  fun `NextClicked registering a brand new account restores the account record and completes registration`() = runTest(testDispatcher) {
+    stubSuccessfulLogin(AccountEntropyPool(VALID_AEP), reregistration = false)
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    coVerify { mockRepository.setRestoreDecision(RestoreDecision.NEW_ACCOUNT) }
+    coVerify { mockRepository.restoreAccountRecord() }
+    assertThat(emittedParentEvents.last()).isEqualTo(RegistrationFlowEvent.RegistrationComplete)
+  }
+
+  @Test
+  fun `NextClicked shows a spinner while the login is in flight`() = runTest(testDispatcher) {
+    stubSuccessfulLogin(AccountEntropyPool(VALID_AEP))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates).hasSize(2)
+    assertThat(emittedStates[0].isLoggingIn).isEqualTo(true)
+    assertThat(emittedStates[1].isLoggingIn).isEqualTo(false)
+  }
+
+  @Test
+  fun `NextClicked with an incorrect recovery password flags the entered login`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.NonSuccess(RegisterAccountError.RegistrationRecoveryPasswordIncorrect("Incorrect"))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates.last().areCredentialsIncorrect).isTrue()
+    assertThat(emittedStates.last().isLoggingIn).isEqualTo(false)
+    assertThat(emittedStates.last().isNextEnabled).isFalse()
+  }
+
+  @Test
+  fun `NextClicked with RegistrationLock retries with the reglock token derived from the recovery key`() = runTest(testDispatcher) {
+    val aep = AccountEntropyPool(VALID_AEP)
+    val reglock = aep.deriveMasterKey().deriveRegistrationLock()
+
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), registrationLock = null, any()) } returns
+      RequestResult.NonSuccess(RegisterAccountError.RegistrationLock(registrationLockResponse()))
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), registrationLock = reglock, any()) } returns
+      successfulResult(aep)
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    coVerify { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), registrationLock = reglock, any()) }
+    assertThat(emittedParentEvents[2])
+      .isInstanceOf<RegistrationFlowEvent.NavigateToScreen>()
+      .prop(RegistrationFlowEvent.NavigateToScreen::route)
+      .isInstanceOf<RegistrationRoute.ArchiveRestoreSelection>()
+  }
+
+  @Test
+  fun `NextClicked still registration locked after providing the reglock token falls back to PIN entry`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.NonSuccess(RegisterAccountError.RegistrationLock(registrationLockResponse()))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates.last().isLoggingIn).isEqualTo(false)
+    assertThat(emittedParentEvents).hasSize(2)
+    assertThat(emittedParentEvents[1])
+      .isInstanceOf<RegistrationFlowEvent.NavigateToScreen>()
+      .prop(RegistrationFlowEvent.NavigateToScreen::route)
+      .isInstanceOf<RegistrationRoute.PinEntryForRegistrationLock>()
+  }
+
+  @Test
+  fun `NextClicked with RateLimited sets loginError to RateLimited`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.NonSuccess(RegisterAccountError.RateLimited(Duration.parse("1m")))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates.last().loginError).isEqualTo(SignalLoginError.RateLimited)
+  }
+
+  @Test
+  fun `NextClicked with InvalidRequest sets loginError to UnknownError`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.NonSuccess(RegisterAccountError.InvalidRequest("Bad request"))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates.last().loginError).isEqualTo(SignalLoginError.UnknownError)
+  }
+
+  @Test
+  fun `NextClicked with a network error sets loginError to NetworkError`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.RetryableNetworkError(IOException("Network error"))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates.last().loginError).isEqualTo(SignalLoginError.NetworkError)
+  }
+
+  @Test
+  fun `NextClicked with an application error sets loginError to UnknownError`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.ApplicationError(RuntimeException("Unexpected"))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+
+    assertThat(emittedStates.last().loginError).isEqualTo(SignalLoginError.UnknownError)
+  }
+
+  @Test(expected = IllegalStateException::class)
+  fun `NextClicked with SessionNotFoundOrNotVerified throws`() = runTest(testDispatcher) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns
+      RequestResult.NonSuccess(RegisterAccountError.SessionNotFoundOrNotVerified("Not found"))
+
+    applyEvent(completeState(), SignalLoginCredentialEntryScreenEvents.NextClicked)
+  }
+
+  private suspend fun applyEvent(state: SignalLoginCredentialEntryState, event: SignalLoginCredentialEntryScreenEvents) {
+    viewModel.applyEvent(state, event, parentEventEmitter, stateEmitter)
+  }
+
+  private suspend fun applyAccountId(value: String): SignalLoginCredentialEntryState {
+    applyEvent(SignalLoginCredentialEntryState(), SignalLoginCredentialEntryScreenEvents.AccountIdChanged(value))
+    return emittedStates.last()
+  }
+
+  private fun completeState(): SignalLoginCredentialEntryState {
+    return SignalLoginCredentialEntryState(
+      accountId = VALID_ACCOUNT_ID,
+      recoveryKey = AepInput.from(VALID_AEP)
+    )
+  }
+
+  private fun registrationLockResponse(): RegistrationLockResponse {
+    return RegistrationLockResponse(
+      timeRemaining = 86400000L,
+      svr2Credentials = SvrCredentials(username = "test-username", password = "test-password")
+    )
+  }
+
+  private fun successfulResult(aep: AccountEntropyPool, reregistration: Boolean = true): RequestResult.Success<RegisteredAccountData> {
+    val keyMaterial = mockk<KeyMaterial>(relaxed = true) {
+      every { accountEntropyPool } returns aep
+    }
+    val response = mockk<RegisterAccountResponse>(relaxed = true) {
+      every { this@mockk.reregistration } returns reregistration
+      every { e164 } returns null
+      every { pni } returns null
+    }
+    return RequestResult.Success(RegisteredAccountData(response, keyMaterial, VALID_ACI))
+  }
+
+  private fun stubSuccessfulLogin(aep: AccountEntropyPool, reregistration: Boolean = true) {
+    coEvery { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) } returns successfulResult(aep, reregistration)
+  }
+
+  private fun stubRemoteBackup(exists: Boolean) {
+    coEvery { mockRepository.getAndMaybeHealRemoteBackupInfo(any()) } returns if (exists) {
+      RequestResult.Success(NetworkController.GetBackupInfoResponse(cdn = 3, backupDir = "dir", mediaDir = "media", backupName = "backup", usedSpace = 1024))
+    } else {
+      RequestResult.NonSuccess(NetworkController.GetBackupInfoError.NoBackup)
+    }
+  }
+}

lib/network/src/main/java/org/signal/network/api/RegistrationApiV2.kt

@@ -280,11 +280,18 @@ class RegistrationApiV2(
    * Submit the cryptographic assets required for an account to use the service.
    * Must provide exactly one of [sessionId], [recoveryPassword], or [receiptCredentialPresentation].
    *
-   * Providing a [receiptCredentialPresentation] (issued by [createLoginPurchaseReceiptCredential]) registers an
-   * account that has no phone number. For that mode, [e164] and [pniPreKeys] must be null, [attributes] must have a
-   * null `pniRegistrationId` and a null `discoverableByPhoneNumber`, and the basic auth username is a placeholder the
-   * service ignores (it must not parse as an e164 or a UUID -- the service reads a UUID username as a request to
-   * recover the account with that ACI; re-registering an existing numberless account isn't supported yet).
+   * There are two ways to register an account that has no phone number, and both require [e164] to be null and
+   * [attributes] to have a null `discoverableByPhoneNumber`:
+   *
+   * - Providing a [receiptCredentialPresentation] (issued by [createLoginPurchaseReceiptCredential]) creates a brand
+   *   new numberless account. [pniPreKeys] and `attributes.pniRegistrationId` must be null. The basic auth username is
+   *   a placeholder the service ignores; it must not parse as an e164 or a UUID, because the service reads a UUID
+   *   username as a request to recover the account with that ACI.
+   * - Providing an [aci] alongside a [recoveryPassword] logs back in to the numberless account with that ACI. The
+   *   ACI is the basic auth username, which is exactly how the service is told which account to recover. A full set of
+   *   [pniPreKeys] and an `attributes.pniRegistrationId` are required even so: the service demands them of any
+   *   recovery-by-identifier, and then ignores them when the recovered account has no phone number. Throwaway key
+   *   material is fine, as long as the pre-keys are signed by the PNI identity key sent alongside them.
    *
    * `POST /v1/registration`
    * - 200: Success, body is the account response
@@ -300,6 +307,7 @@ class RegistrationApiV2(
    *
    * @param e164 The phone number in E.164 format (used as username for basic auth). Null when registering without a phone number.
    * @param password The password for basic auth
+   * @param aci The ACI of the existing numberless account to log back in to, used as the username for basic auth.
    * @param totp A TOTP one-time password, required when recovering an account that has TOTP keys.
    */
   suspend fun registerAccount(
@@ -313,16 +321,23 @@ class RegistrationApiV2(
     pniPreKeys: PreKeyCollection?,
     fcmToken: String?,
     skipDeviceTransfer: Boolean,
+    aci: ACI? = null,
     totp: Int? = null
   ): RequestResult<RegisterAccountResponse, RegisterAccountError> {
-    val phoneNumberless = receiptCredentialPresentation != null
+    val redeemingReceipt = receiptCredentialPresentation != null
+    val phoneNumberless = redeemingReceipt || aci != null
 
     require(listOfNotNull(sessionId, recoveryPassword, receiptCredentialPresentation).size == 1) { "You must supply exactly one of: Session ID, Recovery Password, or Receipt Credential Presentation." }
+    require(aci == null || recoveryPassword != null) { "Must send a recovery password alongside an ACI." }
     if (phoneNumberless) {
       check(phonenumberlessRegistrationAllowed) { "Phone-number-less registration is not allowed in this build!" }
-      require(e164 == null && pniPreKeys == null) { "Must not send an e164 or PNI key material when registering without a phone number." }
-      require(attributes.pniRegistrationId == null) { "Must not send PNI key material when registering without a phone number." }
+      require(e164 == null) { "Must not send an e164 when registering without a phone number." }
       require(attributes.discoverableByPhoneNumber == null) { "Must not set phone number discoverability when registering without a phone number." }
+      if (aci != null) {
+        require(pniPreKeys != null && attributes.pniRegistrationId != null) { "Must send PNI key material when recovering an account by identifier, even though the service ignores it." }
+      } else {
+        require(pniPreKeys == null && attributes.pniRegistrationId == null) { "Must not send PNI key material when registering a new account without a phone number." }
+      }
     } else {
       require(e164 != null && pniPreKeys != null) { "Must send an e164 and PNI key material when registering with a phone number." }
       require(attributes.pniRegistrationId != null) { "Must send PNI key material when registering with a phone number." }
@@ -351,7 +366,7 @@ class RegistrationApiV2(
         host = RequestSpec.Host.Service,
         path = "/v1/registration",
         body = if (phoneNumberless) body.toJsonRequestBodyOmittingNulls() else body.toJsonRequestBody(),
-        auth = RequestSpec.Auth.Header("Authorization", basicAuth(e164 ?: NO_NUMBER_AUTH_USERNAME, password))
+        auth = RequestSpec.Auth.Header("Authorization", basicAuth(e164 ?: aci?.toString() ?: NO_NUMBER_AUTH_USERNAME, password))
       )
     )
 
@@ -359,7 +374,7 @@ class RegistrationApiV2(
       parseSuccess = { SignalJson.json.decodeFromString<RegisterAccountResponse>(it.bodyString()) },
       mapError = { error ->
         when (error.statusCode) {
-          400 -> if (phoneNumberless) RegisterAccountError.InvalidReceiptCredentialPresentation(error.bodyString()) else RegisterAccountError.InvalidRequest(error.bodyString())
+          400 -> if (redeemingReceipt) RegisterAccountError.InvalidReceiptCredentialPresentation(error.bodyString()) else RegisterAccountError.InvalidRequest(error.bodyString())
           422 -> RegisterAccountError.InvalidRequest(error.bodyString())
           401 -> RegisterAccountError.SessionNotFoundOrNotVerified(error.bodyString())
           403 -> RegisterAccountError.RegistrationRecoveryPasswordIncorrect(error.bodyString())
@@ -827,7 +842,10 @@ class RegistrationApiV2(
     val code: String
   )
 
-  /** The PNI properties are all null when registering an account that has no phone number, in which case they are omitted from the request. */
+  /**
+   * The PNI properties are all null when registering a new account that has no phone number, in which case they are
+   * omitted from the request.
+   */
   @OptIn(ExperimentalSerializationApi::class)
   @Serializable
   private class RegisterAccountRequestBody(