From 2c48d40375a631b1e46e261d1f31f44b37a1f313 Mon Sep 17 00:00:00 2001
From: Alex Hart <alex@signal.org>
Date: Thu, 9 Feb 2023 13:59:36 -0400
Subject: [PATCH] Update API endpoints and integration for usernames.

---
 .idea/codeStyles/Project.xml                  |  7 --
 .../securesms/jobs/RefreshOwnProfileJob.java  |  3 -
 .../manage/ManageProfileFragment.java         |  8 +-
 .../manage/UsernameEditRepository.java        | 45 +++++++---
 .../manage/UsernameEditViewModel.java         | 10 ++-
 .../manage/UsernameShareBottomSheet.kt        |  8 +-
 .../profiles/manage/UsernameState.kt          |  5 +-
 .../storage/AccountRecordProcessor.java       | 12 ++-
 .../securesms/storage/StorageSyncHelper.java  |  1 +
 .../securesms/util/CommunicationActions.java  |  2 +-
 .../securesms/util/UsernameUtil.java          | 24 ++++--
 app/src/main/res/layout/copy_button.xml       |  2 +
 .../res/layout/manage_profile_fragment.xml    |  2 +
 .../securesms/util/UsernameUtilTest.java      |  4 +-
 .../api/SignalServiceAccountManager.java      | 29 ++-----
 .../api/storage/SignalAccountRecord.java      | 20 +++++
 .../internal/push/ConfirmUsernameRequest.java | 10 +--
 .../internal/push/PushServiceSocket.java      | 84 +++++++++----------
 .../internal/push/ReserveUsernameRequest.java | 13 +--
 .../push/ReserveUsernameResponse.java         | 18 ++--
 .../internal/push/WhoAmIResponse.java         |  6 +-
 .../src/main/proto/StorageService.proto       |  1 +
 22 files changed, 172 insertions(+), 142 deletions(-)

diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index 6a5c9cbb8c..12d1a43375 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -41,13 +41,6 @@
         </value>
       </option>
     </JavaCodeStyleSettings>
-    <JetCodeStyleSettings>
-      <option name="PACKAGES_TO_USE_STAR_IMPORTS">
-        <value />
-      </option>
-      <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="2147483647" />
-      <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="2147483647" />
-    </JetCodeStyleSettings>
     <codeStyleSettings language="HTML">
       <indentOptions>
         <option name="INDENT_SIZE" value="2" />
diff --git a/app/src/main/java/org/thoughtcrime/securesms/jobs/RefreshOwnProfileJob.java b/app/src/main/java/org/thoughtcrime/securesms/jobs/RefreshOwnProfileJob.java
index 9dfdac71b7..aef468bba0 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/jobs/RefreshOwnProfileJob.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/jobs/RefreshOwnProfileJob.java
@@ -141,9 +141,6 @@ public class RefreshOwnProfileJob extends BaseJob {
     profileAndCredential.getExpiringProfileKeyCredential()
                         .ifPresent(expiringProfileKeyCredential -> setExpiringProfileKeyCredential(self, ProfileKeyUtil.getSelfProfileKey(), expiringProfileKeyCredential));
 
-    String username = ApplicationDependencies.getSignalServiceAccountManager().getWhoAmI().getUsername();
-    SignalDatabase.recipients().setUsername(Recipient.self().getId(), username);
-
     StoryOnboardingDownloadJob.Companion.enqueueIfNeeded();
   }
 
diff --git a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/ManageProfileFragment.java b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/ManageProfileFragment.java
index 5c0ec56519..bed2ec3f24 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/ManageProfileFragment.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/ManageProfileFragment.java
@@ -24,6 +24,8 @@ import com.google.android.material.dialog.MaterialAlertDialogBuilder;
 import com.google.android.material.snackbar.Snackbar;
 
 import org.signal.core.util.logging.Log;
+import org.signal.libsignal.usernames.BaseUsernameException;
+import org.signal.libsignal.usernames.Username;
 import org.thoughtcrime.securesms.AvatarPreviewActivity;
 import org.thoughtcrime.securesms.LoggingFragment;
 import org.thoughtcrime.securesms.R;
@@ -44,6 +46,7 @@ import org.thoughtcrime.securesms.util.NameUtil;
 import org.thoughtcrime.securesms.util.livedata.LiveDataUtil;
 import org.thoughtcrime.securesms.util.navigation.SafeNavigation;
 import org.thoughtcrime.securesms.util.views.SimpleProgressDialog;
+import org.whispersystems.util.Base64UrlSafe;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
@@ -242,13 +245,14 @@ public class ManageProfileFragment extends LoggingFragment {
   private void presentUsername(@Nullable String username) {
     if (username == null || username.isEmpty()) {
       binding.manageProfileUsername.setText(R.string.ManageProfileFragment_username);
+      binding.manageProfileUsernameSubtitle.setText(R.string.ManageProfileFragment_your_username);
       binding.manageProfileUsernameShare.setVisibility(View.GONE);
     } else {
       binding.manageProfileUsername.setText(username);
 
       try {
-        binding.manageProfileUsernameSubtitle.setText(getString(R.string.signal_me_username_url_no_scheme, URLEncoder.encode(username, StandardCharsets.UTF_8.toString())));
-      } catch (UnsupportedEncodingException e) {
+        binding.manageProfileUsernameSubtitle.setText(getString(R.string.signal_me_username_url_no_scheme, Base64UrlSafe.encodeBytesWithoutPadding(Username.hash(username))));
+      } catch (BaseUsernameException e) {
         Log.w(TAG, "Could not format username link", e);
         binding.manageProfileUsernameSubtitle.setText(R.string.ManageProfileFragment_your_username);
       }
diff --git a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditRepository.java b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditRepository.java
index c567e6622f..ef5aaeb18b 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditRepository.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditRepository.java
@@ -5,17 +5,22 @@ import androidx.annotation.WorkerThread;
 
 import org.signal.core.util.Result;
 import org.signal.core.util.logging.Log;
+import org.signal.libsignal.usernames.BaseUsernameException;
+import org.signal.libsignal.usernames.Username;
 import org.thoughtcrime.securesms.database.SignalDatabase;
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
-import org.thoughtcrime.securesms.jobs.MultiDeviceProfileContentUpdateJob;
 import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.util.UsernameUtil;
 import org.whispersystems.signalservice.api.SignalServiceAccountManager;
 import org.whispersystems.signalservice.api.push.exceptions.UsernameIsNotReservedException;
 import org.whispersystems.signalservice.api.push.exceptions.UsernameMalformedException;
 import org.whispersystems.signalservice.api.push.exceptions.UsernameTakenException;
 import org.whispersystems.signalservice.internal.push.ReserveUsernameResponse;
+import org.whispersystems.util.Base64UrlSafe;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import io.reactivex.rxjava3.core.Single;
 import io.reactivex.rxjava3.schedulers.Schedulers;
@@ -30,12 +35,12 @@ class UsernameEditRepository {
     this.accountManager = ApplicationDependencies.getSignalServiceAccountManager();
   }
 
-  @NonNull Single<Result<ReserveUsernameResponse, UsernameSetResult>> reserveUsername(@NonNull String nickname) {
+  @NonNull Single<Result<UsernameState.Reserved, UsernameSetResult>> reserveUsername(@NonNull String nickname) {
     return Single.fromCallable(() -> reserveUsernameInternal(nickname)).subscribeOn(Schedulers.io());
   }
 
-  @NonNull Single<UsernameSetResult> confirmUsername(@NonNull ReserveUsernameResponse reserveUsernameResponse) {
-    return Single.fromCallable(() -> confirmUsernameInternal(reserveUsernameResponse)).subscribeOn(Schedulers.io());
+  @NonNull Single<UsernameSetResult> confirmUsername(@NonNull UsernameState.Reserved reserved) {
+    return Single.fromCallable(() -> confirmUsernameInternal(reserved)).subscribeOn(Schedulers.io());
   }
 
   @NonNull Single<UsernameDeleteResult> deleteUsername() {
@@ -43,11 +48,28 @@ class UsernameEditRepository {
   }
 
   @WorkerThread
-  private @NonNull Result<ReserveUsernameResponse, UsernameSetResult> reserveUsernameInternal(@NonNull String nickname) {
+  private @NonNull Result<UsernameState.Reserved, UsernameSetResult> reserveUsernameInternal(@NonNull String nickname) {
     try {
-      ReserveUsernameResponse username = accountManager.reserveUsername(nickname);
+      List<String> candidates = Username.generateCandidates(nickname, UsernameUtil.MIN_LENGTH, UsernameUtil.MAX_LENGTH);
+      List<String> hashes     = new ArrayList<>();
+
+      for (String candidate : candidates) {
+        byte[] hash = Username.hash(candidate);
+        hashes.add(Base64UrlSafe.encodeBytesWithoutPadding(hash));
+      }
+
+      ReserveUsernameResponse response  = accountManager.reserveUsername(hashes);
+      int                     hashIndex = hashes.indexOf(response.getUsernameHash());
+      if (hashIndex == -1) {
+        Log.w(TAG, "[reserveUsername] The response hash could not be found in our set of hashes.");
+        return Result.failure(UsernameSetResult.CANDIDATE_GENERATION_ERROR);
+      }
+
       Log.i(TAG, "[reserveUsername] Successfully reserved username.");
-      return Result.success(username);
+      return Result.success(new UsernameState.Reserved(candidates.get(hashIndex), response));
+    } catch (BaseUsernameException e) {
+      Log.w(TAG, "[reserveUsername] An error occurred while generating candidates.");
+      return Result.failure(UsernameSetResult.CANDIDATE_GENERATION_ERROR);
     } catch (UsernameTakenException e) {
       Log.w(TAG, "[reserveUsername] Username taken.");
       return Result.failure(UsernameSetResult.USERNAME_UNAVAILABLE);
@@ -61,11 +83,10 @@ class UsernameEditRepository {
   }
 
   @WorkerThread
-  private @NonNull UsernameSetResult confirmUsernameInternal(@NonNull ReserveUsernameResponse reserveUsernameResponse) {
+  private @NonNull UsernameSetResult confirmUsernameInternal(@NonNull UsernameState.Reserved reserved) {
     try {
-      accountManager.confirmUsername(reserveUsernameResponse);
-      SignalDatabase.recipients().setUsername(Recipient.self().getId(), reserveUsernameResponse.getUsername());
-      ApplicationDependencies.getJobManager().add(new MultiDeviceProfileContentUpdateJob());
+      accountManager.confirmUsername(reserved.getUsername(), reserved.getReserveUsernameResponse());
+      SignalDatabase.recipients().setUsername(Recipient.self().getId(), reserved.getUsername());
       Log.i(TAG, "[confirmUsername] Successfully reserved username.");
       return UsernameSetResult.SUCCESS;
     } catch (UsernameTakenException e) {
@@ -94,7 +115,7 @@ class UsernameEditRepository {
   }
 
   enum UsernameSetResult {
-    SUCCESS, USERNAME_UNAVAILABLE, USERNAME_INVALID, NETWORK_ERROR
+    SUCCESS, USERNAME_UNAVAILABLE, USERNAME_INVALID, NETWORK_ERROR, CANDIDATE_GENERATION_ERROR
   }
 
   enum UsernameDeleteResult {
diff --git a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditViewModel.java b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditViewModel.java
index 68a50a55b7..c453756c3f 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditViewModel.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEditViewModel.java
@@ -110,7 +110,7 @@ class UsernameEditViewModel extends ViewModel {
 
     uiState.update(state -> new State(ButtonState.SUBMIT_LOADING, UsernameStatus.NONE, state.usernameState));
 
-    Disposable confirmUsernameDisposable = repo.confirmUsername(((UsernameState.Reserved) usernameState).getReserveUsernameResponse())
+    Disposable confirmUsernameDisposable = repo.confirmUsername((UsernameState.Reserved) usernameState)
                                                .subscribe(result -> {
                                                  String nickname = usernameState.getNickname();
 
@@ -181,8 +181,8 @@ class UsernameEditViewModel extends ViewModel {
     uiState.update(state -> new State(ButtonState.SUBMIT_DISABLED, UsernameStatus.NONE, UsernameState.Loading.INSTANCE));
     Disposable reserveDisposable = repo.reserveUsername(nickname).subscribe(result -> {
       result.either(
-          reserveUsernameJsonResponse -> {
-            uiState.update(state -> new State(ButtonState.SUBMIT, UsernameStatus.NONE, new UsernameState.Reserved(reserveUsernameJsonResponse)));
+          reserved -> {
+            uiState.update(state -> new State(ButtonState.SUBMIT, UsernameStatus.NONE, reserved));
             return null;
           },
           failure -> {
@@ -199,6 +199,10 @@ class UsernameEditViewModel extends ViewModel {
                 uiState.update(state -> new State(ButtonState.SUBMIT, UsernameStatus.NONE, UsernameState.NoUsername.INSTANCE));
                 events.onNext(Event.NETWORK_FAILURE);
                 break;
+              case CANDIDATE_GENERATION_ERROR:
+                // TODO -- Retry
+                uiState.update(state -> new State(ButtonState.SUBMIT_DISABLED, UsernameStatus.TAKEN, UsernameState.NoUsername.INSTANCE));
+                break;
             }
 
             return null;
diff --git a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameShareBottomSheet.kt b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameShareBottomSheet.kt
index 91c87723b5..1b88b37162 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameShareBottomSheet.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameShareBottomSheet.kt
@@ -9,6 +9,7 @@ import androidx.core.content.ContextCompat
 import androidx.fragment.app.setFragmentResult
 import androidx.navigation.fragment.findNavController
 import org.signal.core.util.DimensionUnit
+import org.signal.libsignal.usernames.Username
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.components.settings.DSLConfiguration
 import org.thoughtcrime.securesms.components.settings.DSLSettingsAdapter
@@ -19,8 +20,7 @@ import org.thoughtcrime.securesms.recipients.Recipient
 import org.thoughtcrime.securesms.util.FragmentResultContract
 import org.thoughtcrime.securesms.util.LifecycleDisposable
 import org.thoughtcrime.securesms.util.Util
-import java.net.URLEncoder
-import java.nio.charset.StandardCharsets
+import org.whispersystems.util.Base64UrlSafe
 
 /**
  * Allows the user to either share their username directly or to copy it to their clipboard.
@@ -71,7 +71,7 @@ class UsernameShareBottomSheet : DSLSettingsBottomSheetFragment() {
 
       customPref(
         CopyButton.Model(
-          text = getString(R.string.signal_me_username_url, URLEncoder.encode(username, StandardCharsets.UTF_8.toString())),
+          text = getString(R.string.signal_me_username_url, Base64UrlSafe.encodeBytesWithoutPadding(Username.hash(username))),
           onClick = {
             copyToClipboard(it)
           }
@@ -82,7 +82,7 @@ class UsernameShareBottomSheet : DSLSettingsBottomSheetFragment() {
 
       customPref(
         ShareButton.Model(
-          text = getString(R.string.signal_me_username_url, URLEncoder.encode(username, StandardCharsets.UTF_8.toString())),
+          text = getString(R.string.signal_me_username_url, Base64UrlSafe.encodeBytesWithoutPadding(Username.hash(username))),
           onClick = {
             openShareSheet(it.text)
           }
diff --git a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameState.kt b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameState.kt
index 1a0c3e3b46..a4b2ebcee7 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameState.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameState.kt
@@ -17,10 +17,9 @@ sealed class UsernameState {
   object NoUsername : UsernameState()
 
   data class Reserved(
+    override val username: String,
     val reserveUsernameResponse: ReserveUsernameResponse
-  ) : UsernameState() {
-    override val username: String? = reserveUsernameResponse.username
-  }
+  ) : UsernameState()
 
   data class Set(
     override val username: String
diff --git a/app/src/main/java/org/thoughtcrime/securesms/storage/AccountRecordProcessor.java b/app/src/main/java/org/thoughtcrime/securesms/storage/AccountRecordProcessor.java
index 5113e1f6d7..37016b9fbd 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/storage/AccountRecordProcessor.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/storage/AccountRecordProcessor.java
@@ -125,8 +125,9 @@ public class AccountRecordProcessor extends DefaultStorageRecordProcessor<Signal
     boolean                              storiesDisabled               = remote.isStoriesDisabled();
     boolean                              hasReadOnboardingStory        = remote.hasReadOnboardingStory() || remote.hasViewedOnboardingStory() || local.hasReadOnboardingStory() || local.hasViewedOnboardingStory() ;
     boolean                              hasSeenGroupStoryEducation    = remote.hasSeenGroupStoryEducationSheet() || local.hasSeenGroupStoryEducationSheet();
-    boolean                              matchesRemote                 = doParamsMatch(remote, unknownFields, givenName, familyName, avatarUrlPath, profileKey, noteToSelfArchived, noteToSelfForcedUnread, readReceipts, typingIndicators, sealedSenderIndicators, linkPreviews, phoneNumberSharingMode, unlisted, pinnedConversations, preferContactAvatars, payments, universalExpireTimer, primarySendsSms, e164, defaultReactions, subscriber, displayBadgesOnProfile, subscriptionManuallyCancelled, keepMutedChatsArchived, hasSetMyStoriesPrivacy, hasViewedOnboardingStory, storiesDisabled, storyViewReceiptsState, hasReadOnboardingStory);
-    boolean                              matchesLocal                  = doParamsMatch(local, unknownFields, givenName, familyName, avatarUrlPath, profileKey, noteToSelfArchived, noteToSelfForcedUnread, readReceipts, typingIndicators, sealedSenderIndicators, linkPreviews, phoneNumberSharingMode, unlisted, pinnedConversations, preferContactAvatars, payments, universalExpireTimer, primarySendsSms, e164, defaultReactions, subscriber, displayBadgesOnProfile, subscriptionManuallyCancelled, keepMutedChatsArchived, hasSetMyStoriesPrivacy, hasViewedOnboardingStory, storiesDisabled, storyViewReceiptsState, hasReadOnboardingStory);
+    String                               username                      = remote.getUsername();
+    boolean                              matchesRemote                 = doParamsMatch(remote, unknownFields, givenName, familyName, avatarUrlPath, profileKey, noteToSelfArchived, noteToSelfForcedUnread, readReceipts, typingIndicators, sealedSenderIndicators, linkPreviews, phoneNumberSharingMode, unlisted, pinnedConversations, preferContactAvatars, payments, universalExpireTimer, primarySendsSms, e164, defaultReactions, subscriber, displayBadgesOnProfile, subscriptionManuallyCancelled, keepMutedChatsArchived, hasSetMyStoriesPrivacy, hasViewedOnboardingStory, storiesDisabled, storyViewReceiptsState, hasReadOnboardingStory, username);
+    boolean                              matchesLocal                  = doParamsMatch(local, unknownFields, givenName, familyName, avatarUrlPath, profileKey, noteToSelfArchived, noteToSelfForcedUnread, readReceipts, typingIndicators, sealedSenderIndicators, linkPreviews, phoneNumberSharingMode, unlisted, pinnedConversations, preferContactAvatars, payments, universalExpireTimer, primarySendsSms, e164, defaultReactions, subscriber, displayBadgesOnProfile, subscriptionManuallyCancelled, keepMutedChatsArchived, hasSetMyStoriesPrivacy, hasViewedOnboardingStory, storiesDisabled, storyViewReceiptsState, hasReadOnboardingStory, username);
 
     if (matchesRemote) {
       return remote;
@@ -163,6 +164,7 @@ public class AccountRecordProcessor extends DefaultStorageRecordProcessor<Signal
                                     .setStoriesDisabled(storiesDisabled)
                                     .setHasReadOnboardingStory(hasReadOnboardingStory)
                                     .setHasSeenGroupStoryEducationSheet(hasSeenGroupStoryEducation)
+                                    .setUsername(username)
                                     .build();
     }
   }
@@ -211,7 +213,8 @@ public class AccountRecordProcessor extends DefaultStorageRecordProcessor<Signal
                                        boolean hasViewedOnboardingStory,
                                        boolean storiesDisabled,
                                        @NonNull OptionalBool storyViewReceiptsState,
-                                       boolean hasReadOnboardingStory)
+                                       boolean hasReadOnboardingStory,
+                                       @Nullable String username)
   {
     return Arrays.equals(contact.serializeUnknownFields(), unknownFields)        &&
            Objects.equals(contact.getGivenName().orElse(""), givenName)          &&
@@ -241,6 +244,7 @@ public class AccountRecordProcessor extends DefaultStorageRecordProcessor<Signal
            contact.hasViewedOnboardingStory() == hasViewedOnboardingStory &&
            contact.isStoriesDisabled() == storiesDisabled &&
            contact.getStoryViewReceiptsState().equals(storyViewReceiptsState) &&
-           contact.hasReadOnboardingStory() == hasReadOnboardingStory;
+           contact.hasReadOnboardingStory() == hasReadOnboardingStory &&
+           Objects.equals(contact.getUsername(), username);
   }
 }
diff --git a/app/src/main/java/org/thoughtcrime/securesms/storage/StorageSyncHelper.java b/app/src/main/java/org/thoughtcrime/securesms/storage/StorageSyncHelper.java
index 21cf4a972c..a8e939b6be 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/storage/StorageSyncHelper.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/storage/StorageSyncHelper.java
@@ -153,6 +153,7 @@ public final class StorageSyncHelper {
                                                          .setStoryViewReceiptsState(storyViewReceiptsState)
                                                          .setHasReadOnboardingStory(hasReadOnboardingStory)
                                                          .setHasSeenGroupStoryEducationSheet(SignalStore.storyValues().getUserHasSeenGroupStoryEducationSheet())
+                                                         .setUsername(self.getUsername().orElse(null))
                                                          .build();
 
     return SignalStorageRecord.forAccount(account);
diff --git a/app/src/main/java/org/thoughtcrime/securesms/util/CommunicationActions.java b/app/src/main/java/org/thoughtcrime/securesms/util/CommunicationActions.java
index 5f5e206b28..4e663bcca7 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/util/CommunicationActions.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/util/CommunicationActions.java
@@ -291,7 +291,7 @@ public class CommunicationActions {
             }
           }
         } else {
-          Optional<ServiceId> serviceId = UsernameUtil.fetchAciForUsername(username);
+          Optional<ServiceId> serviceId = UsernameUtil.fetchAciForUsernameHash(username);
           if (serviceId.isPresent()) {
             recipient = Recipient.externalUsername(serviceId.get(), username);
           }
diff --git a/app/src/main/java/org/thoughtcrime/securesms/util/UsernameUtil.java b/app/src/main/java/org/thoughtcrime/securesms/util/UsernameUtil.java
index 71f38ca50e..c5ea443867 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/util/UsernameUtil.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/util/UsernameUtil.java
@@ -7,13 +7,15 @@ import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
 
 import org.signal.core.util.logging.Log;
+import org.signal.libsignal.usernames.BaseUsernameException;
+import org.signal.libsignal.usernames.Username;
 import org.thoughtcrime.securesms.database.SignalDatabase;
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientId;
-import org.whispersystems.signalservice.api.profiles.SignalServiceProfile;
 import org.whispersystems.signalservice.api.push.ACI;
 import org.whispersystems.signalservice.api.push.ServiceId;
+import org.whispersystems.util.Base64UrlSafe;
 
 import java.io.IOException;
 import java.util.Locale;
@@ -24,10 +26,10 @@ public class UsernameUtil {
 
   private static final String TAG = Log.tag(UsernameUtil.class);
 
-  public static final int MIN_LENGTH = 4;
-  public static final int MAX_LENGTH = 26;
+  public static final int MIN_LENGTH = 3;
+  public static final int MAX_LENGTH = 32;
 
-  private static final Pattern FULL_PATTERN        = Pattern.compile("^[a-z_][a-z0-9_]{3,25}$", Pattern.CASE_INSENSITIVE);
+  private static final Pattern FULL_PATTERN        = Pattern.compile(String.format(Locale.US, "^[a-zA-Z_][a-zA-Z0-9_]{%d,%d}$", MIN_LENGTH - 1, MAX_LENGTH - 1), Pattern.CASE_INSENSITIVE);
   private static final Pattern DIGIT_START_PATTERN = Pattern.compile("^[0-9].*$");
 
   public static boolean isValidUsernameForSearch(@Nullable String value) {
@@ -66,9 +68,19 @@ public class UsernameUtil {
       }
     }
 
+    Log.d(TAG, "No local user with this username. Searching remotely.");
     try {
-      Log.d(TAG, "No local user with this username. Searching remotely.");
-      ACI aci = ApplicationDependencies.getSignalServiceAccountManager().getAciByUsername(username);
+      return fetchAciForUsernameHash(Base64UrlSafe.encodeBytesWithoutPadding(Username.hash(username)));
+    } catch (BaseUsernameException e) {
+      return Optional.empty();
+    }
+  }
+
+  @WorkerThread
+  public static @NonNull Optional<ServiceId> fetchAciForUsernameHash(@NonNull String base64UrlSafeEncodedUsernameHash) {
+    try {
+      ACI aci = ApplicationDependencies.getSignalServiceAccountManager()
+                                       .getAciByUsernameHash(base64UrlSafeEncodedUsernameHash);
       return Optional.ofNullable(aci);
     } catch (IOException e) {
       return Optional.empty();
diff --git a/app/src/main/res/layout/copy_button.xml b/app/src/main/res/layout/copy_button.xml
index 529ee49feb..41ed1db634 100644
--- a/app/src/main/res/layout/copy_button.xml
+++ b/app/src/main/res/layout/copy_button.xml
@@ -7,6 +7,8 @@
     android:layout_height="wrap_content"
     android:layout_marginStart="@dimen/dsl_settings_gutter"
     android:layout_marginEnd="@dimen/dsl_settings_gutter"
+    android:ellipsize="end"
+    android:lines="1"
     android:minHeight="56dp"
     android:paddingHorizontal="16dp"
     android:textAlignment="viewStart"
diff --git a/app/src/main/res/layout/manage_profile_fragment.xml b/app/src/main/res/layout/manage_profile_fragment.xml
index 98773e6d81..6531fb9e6e 100644
--- a/app/src/main/res/layout/manage_profile_fragment.xml
+++ b/app/src/main/res/layout/manage_profile_fragment.xml
@@ -186,6 +186,8 @@
                     style="@style/Signal.Text.Preview"
                     android:layout_width="0dp"
                     android:layout_height="wrap_content"
+                    android:ellipsize="end"
+                    android:lines="1"
                     android:text="@string/ManageProfileFragment_your_username"
                     android:textColor="@color/signal_text_secondary"
                     app:layout_constraintBottom_toBottomOf="parent"
diff --git a/app/src/test/java/org/thoughtcrime/securesms/util/UsernameUtilTest.java b/app/src/test/java/org/thoughtcrime/securesms/util/UsernameUtilTest.java
index 8925473f6d..00f0cce462 100644
--- a/app/src/test/java/org/thoughtcrime/securesms/util/UsernameUtilTest.java
+++ b/app/src/test/java/org/thoughtcrime/securesms/util/UsernameUtilTest.java
@@ -11,12 +11,12 @@ public class UsernameUtilTest {
   public void checkUsername_tooShort() {
     assertEquals(UsernameUtil.InvalidReason.TOO_SHORT, UsernameUtil.checkUsername(null).get());
     assertEquals(UsernameUtil.InvalidReason.TOO_SHORT, UsernameUtil.checkUsername("").get());
-    assertEquals(UsernameUtil.InvalidReason.TOO_SHORT, UsernameUtil.checkUsername("abc").get());
+    assertEquals(UsernameUtil.InvalidReason.TOO_SHORT, UsernameUtil.checkUsername("ab").get());
   }
 
   @Test
   public void checkUsername_tooLong() {
-    assertEquals(UsernameUtil.InvalidReason.TOO_LONG, UsernameUtil.checkUsername("abcdefghijklmnopqrstuvwxyz1").get());
+    assertEquals(UsernameUtil.InvalidReason.TOO_LONG, UsernameUtil.checkUsername("abcdefghijklmnopqrstuvwxyz1234567").get());
   }
 
   @Test
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java
index ab87d047ea..5a058dab41 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java
@@ -20,7 +20,6 @@ import org.signal.libsignal.zkgroup.profiles.ExpiringProfileKeyCredential;
 import org.signal.libsignal.zkgroup.profiles.ProfileKey;
 import org.whispersystems.signalservice.api.account.AccountAttributes;
 import org.whispersystems.signalservice.api.account.ChangePhoneNumberRequest;
-import org.whispersystems.signalservice.api.crypto.InvalidCiphertextException;
 import org.whispersystems.signalservice.api.crypto.ProfileCipher;
 import org.whispersystems.signalservice.api.crypto.ProfileCipherOutputStream;
 import org.whispersystems.signalservice.api.groupsv2.ClientZkOperations;
@@ -55,19 +54,11 @@ import org.whispersystems.signalservice.api.util.CredentialsProvider;
 import org.whispersystems.signalservice.api.util.Preconditions;
 import org.whispersystems.signalservice.internal.ServiceResponse;
 import org.whispersystems.signalservice.internal.configuration.SignalServiceConfiguration;
-import org.whispersystems.signalservice.internal.contacts.crypto.ContactDiscoveryCipher;
-import org.whispersystems.signalservice.internal.contacts.crypto.Quote;
-import org.whispersystems.signalservice.internal.contacts.crypto.RemoteAttestation;
-import org.whispersystems.signalservice.internal.contacts.crypto.UnauthenticatedQuoteException;
-import org.whispersystems.signalservice.internal.contacts.crypto.UnauthenticatedResponseException;
-import org.whispersystems.signalservice.internal.contacts.entities.DiscoveryRequest;
-import org.whispersystems.signalservice.internal.contacts.entities.DiscoveryResponse;
 import org.whispersystems.signalservice.internal.crypto.PrimaryProvisioningCipher;
 import org.whispersystems.signalservice.internal.push.AuthCredentials;
 import org.whispersystems.signalservice.internal.push.CdsiAuthResponse;
 import org.whispersystems.signalservice.internal.push.ProfileAvatarData;
 import org.whispersystems.signalservice.internal.push.PushServiceSocket;
-import org.whispersystems.signalservice.internal.push.RemoteAttestationUtil;
 import org.whispersystems.signalservice.internal.push.RemoteConfigResponse;
 import org.whispersystems.signalservice.internal.push.RequestVerificationCodeResponse;
 import org.whispersystems.signalservice.internal.push.ReserveUsernameResponse;
@@ -85,13 +76,10 @@ import org.whispersystems.signalservice.internal.util.StaticCredentialsProvider;
 import org.whispersystems.signalservice.internal.util.Util;
 import org.whispersystems.util.Base64;
 
-import java.io.ByteArrayInputStream;
-import java.io.DataInputStream;
 import java.io.IOException;
 import java.security.KeyStore;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
-import java.security.SignatureException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -102,7 +90,6 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
-import java.util.UUID;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -823,20 +810,16 @@ public class SignalServiceAccountManager {
     }
   }
 
-  public ACI getAciByUsername(String username) throws IOException {
-    return this.pushServiceSocket.getAciByUsername(username);
+  public ACI getAciByUsernameHash(String usernameHash) throws IOException {
+    return this.pushServiceSocket.getAciByUsernameHash(usernameHash);
   }
 
-  public void setUsername(String nickname, String existingUsername) throws IOException {
-    this.pushServiceSocket.setUsername(nickname, existingUsername);
+  public ReserveUsernameResponse reserveUsername(List<String> usernameHashes) throws IOException {
+    return this.pushServiceSocket.reserveUsername(usernameHashes);
   }
 
-  public ReserveUsernameResponse reserveUsername(String nickname) throws IOException {
-    return this.pushServiceSocket.reserveUsername(nickname);
-  }
-
-  public void confirmUsername(ReserveUsernameResponse reserveUsernameResponse) throws IOException {
-    this.pushServiceSocket.confirmUsername(reserveUsernameResponse);
+  public void confirmUsername(String username, ReserveUsernameResponse reserveUsernameResponse) throws IOException {
+    this.pushServiceSocket.confirmUsername(username, reserveUsernameResponse);
   }
 
   public void deleteUsername() throws IOException {
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/storage/SignalAccountRecord.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/storage/SignalAccountRecord.java
index dffa9f0f19..c4cb2f7c03 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/storage/SignalAccountRecord.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/storage/SignalAccountRecord.java
@@ -19,6 +19,8 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 
+import javax.annotation.Nullable;
+
 public final class SignalAccountRecord implements SignalRecord {
 
   private static final String TAG = SignalAccountRecord.class.getSimpleName();
@@ -195,6 +197,10 @@ public final class SignalAccountRecord implements SignalRecord {
         diff.add("HasSeenGroupStoryEducationSheet");
       }
 
+      if (!Objects.equals(getUsername(), that.getUsername())) {
+        diff.add("Username");
+      }
+
       return diff.toString();
     } else {
       return "Different class. " + getClass().getSimpleName() + " | " + other.getClass().getSimpleName();
@@ -325,6 +331,10 @@ public final class SignalAccountRecord implements SignalRecord {
     return proto.getHasSeenGroupStoryEducationSheet();
   }
 
+  public @Nullable String getUsername() {
+    return proto.getUsername();
+  }
+
   public AccountRecord toProto() {
     return proto;
   }
@@ -697,6 +707,16 @@ public final class SignalAccountRecord implements SignalRecord {
       return this;
     }
 
+    public Builder setUsername(@Nullable String username) {
+      if (username == null || username.isEmpty()) {
+        builder.clearUsername();
+      } else {
+        builder.setUsername(username);
+      }
+
+      return this;
+    }
+
     private static AccountRecord.Builder parseUnknowns(byte[] serializedUnknowns) {
       try {
         return AccountRecord.parseFrom(serializedUnknowns).toBuilder();
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ConfirmUsernameRequest.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ConfirmUsernameRequest.java
index 9e2c2612b2..cd617ace4b 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ConfirmUsernameRequest.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ConfirmUsernameRequest.java
@@ -4,13 +4,13 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 
 class ConfirmUsernameRequest {
   @JsonProperty
-  private String usernameToConfirm;
+  private String usernameHash;
 
   @JsonProperty
-  private String reservationToken;
+  private String zkProof;
 
-  ConfirmUsernameRequest(String usernameToConfirm, String reservationToken) {
-    this.usernameToConfirm = usernameToConfirm;
-    this.reservationToken  = reservationToken;
+  ConfirmUsernameRequest(String usernameHash, String zkProof) {
+    this.usernameHash = usernameHash;
+    this.zkProof      = zkProof;
   }
 }
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java
index a97eb1fdfd..be7175b174 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java
@@ -19,6 +19,8 @@ import org.signal.libsignal.protocol.state.PreKeyBundle;
 import org.signal.libsignal.protocol.state.PreKeyRecord;
 import org.signal.libsignal.protocol.state.SignedPreKeyRecord;
 import org.signal.libsignal.protocol.util.Pair;
+import org.signal.libsignal.usernames.BaseUsernameException;
+import org.signal.libsignal.usernames.Username;
 import org.signal.libsignal.zkgroup.VerificationFailedException;
 import org.signal.libsignal.zkgroup.profiles.ClientZkProfileOperations;
 import org.signal.libsignal.zkgroup.profiles.ExpiringProfileKeyCredential;
@@ -97,8 +99,6 @@ import org.whispersystems.signalservice.internal.configuration.SignalCdnUrl;
 import org.whispersystems.signalservice.internal.configuration.SignalProxy;
 import org.whispersystems.signalservice.internal.configuration.SignalServiceConfiguration;
 import org.whispersystems.signalservice.internal.configuration.SignalUrl;
-import org.whispersystems.signalservice.internal.contacts.entities.DiscoveryRequest;
-import org.whispersystems.signalservice.internal.contacts.entities.DiscoveryResponse;
 import org.whispersystems.signalservice.internal.contacts.entities.KeyBackupRequest;
 import org.whispersystems.signalservice.internal.contacts.entities.KeyBackupResponse;
 import org.whispersystems.signalservice.internal.contacts.entities.TokenResponse;
@@ -161,7 +161,6 @@ import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.TrustManager;
 import javax.net.ssl.X509TrustManager;
@@ -202,10 +201,10 @@ public class PushServiceSocket {
   private static final String REGISTRATION_LOCK_PATH     = "/v1/accounts/registration_lock";
   private static final String REQUEST_PUSH_CHALLENGE     = "/v1/accounts/fcm/preauth/%s/%s";
   private static final String WHO_AM_I                   = "/v1/accounts/whoami";
-  private static final String GET_USERNAME_PATH          = "/v1/accounts/username/%s";
-  private static final String MODIFY_USERNAME_PATH       = "/v1/accounts/username";
-  private static final String RESERVE_USERNAME_PATH      = "/v1/accounts/username/reserved";
-  private static final String CONFIRM_USERNAME_PATH      = "/v1/accounts/username/confirm";
+  private static final String GET_USERNAME_PATH          = "/v1/accounts/username_hash/%s";
+  private static final String MODIFY_USERNAME_PATH       = "/v1/accounts/username_hash";
+  private static final String RESERVE_USERNAME_PATH      = "/v1/accounts/username_hash/reserve";
+  private static final String CONFIRM_USERNAME_PATH      = "/v1/accounts/username_hash/confirm";
   private static final String DELETE_ACCOUNT_PATH        = "/v1/accounts/me";
   private static final String CHANGE_NUMBER_PATH         = "/v1/accounts/number";
   private static final String IDENTIFIER_REGISTERED_PATH = "/v1/accounts/account/%s";
@@ -896,7 +895,9 @@ public class PushServiceSocket {
   }
 
   /**
-   * Gets the ACI for the given username, if it exists. This is an unauthenticated request.
+   * GET /v1/accounts/username_hash/{usernameHash}
+   *
+   * Gets the ACI for the given username hash, if it exists. This is an unauthenticated request.
    *
    * This network request can have the following error responses:
    * <ul>
@@ -905,13 +906,13 @@ public class PushServiceSocket {
    *   <li>400 - Bad Request. The request included authentication.</li>
    * </ul>
    *
-   * @param username The username to look up.
+   * @param usernameHash The usernameHash to look up.
    * @return The ACI for the given username if it exists.
    * @throws IOException if a network exception occurs.
    */
-  public @NonNull ACI getAciByUsername(String username) throws IOException {
+  public @NonNull ACI getAciByUsernameHash(String usernameHash) throws IOException {
     String response = makeServiceRequestWithoutAuthentication(
-        String.format(GET_USERNAME_PATH, URLEncoder.encode(username, StandardCharsets.UTF_8.toString())),
+        String.format(GET_USERNAME_PATH, URLEncoder.encode(usernameHash, StandardCharsets.UTF_8.toString())),
         "GET",
         null,
         NO_HEADERS,
@@ -927,38 +928,16 @@ public class PushServiceSocket {
   }
 
   /**
-   * Set the username for the account without seeing the discriminator first.
-   *
-   * @param nickname          The user-supplied nickname, which must meet the requirements for usernames.
-   * @param existingUsername  (Optional) If the account has a current username, indicates what the client thinks the current username is. Allows the server to
-   *                          deduplicate repeated requests.
-   * @return                  The username as set by the server, which includes both the nickname and discriminator.
-   * @throws IOException      Thrown when the username is invalid or taken, or when another network error occurs.
-   */
-  public @NonNull String setUsername(@NonNull String nickname, @Nullable String existingUsername) throws IOException {
-    SetUsernameRequest setUsernameRequest = new SetUsernameRequest(nickname, existingUsername);
-
-    String responseString = makeServiceRequest(MODIFY_USERNAME_PATH, "PUT", JsonUtil.toJson(setUsernameRequest), NO_HEADERS, (responseCode, body) -> {
-      switch (responseCode) {
-        case 422: throw new UsernameMalformedException();
-        case 409: throw new UsernameTakenException();
-      }
-    }, Optional.empty());
-
-    SetUsernameResponse response = JsonUtil.fromJsonResponse(responseString, SetUsernameResponse.class);
-    return response.getUsername();
-  }
-
-  /**
+   * PUT /v1/accounts/username_hash/reserve
    * Reserve a username for the account. This replaces an existing reservation if one exists. The username is guaranteed to be available for 5 minutes and can
    * be confirmed with confirmUsername.
    *
-   * @param nickname          The user-supplied nickname, which must meet the requirements for usernames.
+   * @param usernameHashes    A list of hashed usernames encoded as web-safe base64 strings without padding. The list will have a max length of 20, and each hash will be 32 bytes.
    * @return                  The reserved username. It is available for confirmation for 5 minutes.
    * @throws IOException      Thrown when the username is invalid or taken, or when another network error occurs.
    */
-  public @NonNull ReserveUsernameResponse reserveUsername(@NonNull String nickname) throws IOException {
-    ReserveUsernameRequest reserveUsernameRequest = new ReserveUsernameRequest(nickname);
+  public @NonNull ReserveUsernameResponse reserveUsername(@NonNull List<String> usernameHashes) throws IOException {
+    ReserveUsernameRequest reserveUsernameRequest = new ReserveUsernameRequest(usernameHashes);
 
     String responseString = makeServiceRequest(RESERVE_USERNAME_PATH, "PUT", JsonUtil.toJson(reserveUsernameRequest), NO_HEADERS, (responseCode, body) -> {
       switch (responseCode) {
@@ -971,20 +950,33 @@ public class PushServiceSocket {
   }
 
   /**
+   * PUT /v1/accounts/username_hash/confirm
    * Set a previously reserved username for the account.
    *
+   * @param username                The username the user wishes to confirm. For example, myusername.27
    * @param reserveUsernameResponse The response object from the reservation
-   * @throws IOException                Thrown when the username is invalid or taken, or when another network error occurs.
+   * @throws IOException            Thrown when the username is invalid or taken, or when another network error occurs.
    */
-  public void confirmUsername(ReserveUsernameResponse reserveUsernameResponse) throws IOException {
-    ConfirmUsernameRequest confirmUsernameRequest = new ConfirmUsernameRequest(reserveUsernameResponse.getUsername(), reserveUsernameResponse.getReservationToken());
+  public void confirmUsername(String username, ReserveUsernameResponse reserveUsernameResponse) throws IOException {
+    try {
+      byte[] randomness = new byte[32];
+      random.nextBytes(randomness);
 
-    makeServiceRequest(CONFIRM_USERNAME_PATH, "PUT", JsonUtil.toJson(confirmUsernameRequest), NO_HEADERS, (responseCode, body) -> {
-      switch (responseCode) {
-        case 409: throw new UsernameIsNotReservedException();
-        case 410: throw new UsernameTakenException();
-      }
-    }, Optional.empty());
+      byte[]                 proof                  = Username.generateProof(username, randomness);
+      ConfirmUsernameRequest confirmUsernameRequest = new ConfirmUsernameRequest(reserveUsernameResponse.getUsernameHash(),
+                                                                                 Base64UrlSafe.encodeBytesWithoutPadding(proof));
+
+      makeServiceRequest(CONFIRM_USERNAME_PATH, "PUT", JsonUtil.toJson(confirmUsernameRequest), NO_HEADERS, (responseCode, body) -> {
+        switch (responseCode) {
+          case 409:
+            throw new UsernameIsNotReservedException();
+          case 410:
+            throw new UsernameTakenException();
+        }
+      }, Optional.empty());
+    } catch (BaseUsernameException e) {
+      throw new IOException(e);
+    }
   }
 
   /**
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameRequest.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameRequest.java
index 8435c8cedd..eec41934ab 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameRequest.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameRequest.java
@@ -2,15 +2,18 @@ package org.whispersystems.signalservice.internal.push;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import java.util.Collections;
+import java.util.List;
+
 class ReserveUsernameRequest {
   @JsonProperty
-  private String nickname;
+  private List<String> usernameHashes;
 
-  ReserveUsernameRequest(String nickname) {
-    this.nickname = nickname;
+  ReserveUsernameRequest(List<String> usernameHashes) {
+    this.usernameHashes = Collections.unmodifiableList(usernameHashes);
   }
 
-  String getNickname() {
-    return nickname;
+  List<String> getUsernameHashes() {
+    return usernameHashes;
   }
 }
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameResponse.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameResponse.java
index d3d20b12a9..011c0b7268 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameResponse.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/ReserveUsernameResponse.java
@@ -4,26 +4,18 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 
 public class ReserveUsernameResponse {
   @JsonProperty
-  private String username;
-
-  @JsonProperty
-  private String reservationToken;
+  private String usernameHash;
 
   ReserveUsernameResponse() {}
 
   /**
    * Visible for testing.
    */
-  public ReserveUsernameResponse(String username, String reservationToken) {
-    this.username         = username;
-    this.reservationToken = reservationToken;
+  public ReserveUsernameResponse(String usernameHash) {
+    this.usernameHash = usernameHash;
   }
 
-  public String getUsername() {
-    return username;
-  }
-
-  String getReservationToken() {
-    return reservationToken;
+  public String getUsernameHash() {
+    return usernameHash;
   }
 }
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/WhoAmIResponse.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/WhoAmIResponse.java
index af9180b885..2920ccd728 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/WhoAmIResponse.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/WhoAmIResponse.java
@@ -13,7 +13,7 @@ public class WhoAmIResponse {
   public String number;
 
   @JsonProperty
-  public String username;
+  public String usernameHash;
 
   public String getAci() {
     return uuid;
@@ -27,7 +27,7 @@ public class WhoAmIResponse {
     return number;
   }
 
-  public String getUsername() {
-    return username;
+  public String getUsernameHash() {
+    return usernameHash;
   }
 }
diff --git a/libsignal/service/src/main/proto/StorageService.proto b/libsignal/service/src/main/proto/StorageService.proto
index 80f02efba1..4cf7b47d7e 100644
--- a/libsignal/service/src/main/proto/StorageService.proto
+++ b/libsignal/service/src/main/proto/StorageService.proto
@@ -185,6 +185,7 @@ message AccountRecord {
            OptionalBool           storyViewReceiptsEnabled        = 30;
            bool                   hasReadOnboardingStory          = 31;
            bool                   hasSeenGroupStoryEducationSheet = 32;
+           string                 username                        = 33;
 }
 
 message StoryDistributionListRecord {