Use RemoteConfig for UsePqRatchet.

Co-authored-by: Greyson Parrelli <greyson@signal.org>

app/src/androidTest/java/org/thoughtcrime/securesms/testing/BobClient.kt

@@ -6,6 +6,7 @@ import org.signal.libsignal.protocol.IdentityKey
 import org.signal.libsignal.protocol.IdentityKeyPair
 import org.signal.libsignal.protocol.SessionBuilder
 import org.signal.libsignal.protocol.SignalProtocolAddress
+import org.signal.libsignal.protocol.UsePqRatchet
 import org.signal.libsignal.protocol.ecc.ECKeyPair
 import org.signal.libsignal.protocol.groups.state.SenderKeyRecord
 import org.signal.libsignal.protocol.state.IdentityKeyStore
@@ -68,7 +69,7 @@ class BobClient(val serviceId: ServiceId, val e164: String, val identityKeyPair:
 
     if (!aciStore.containsSession(getAliceProtocolAddress())) {
       val sessionBuilder = SignalSessionBuilder(sessionLock, SessionBuilder(aciStore, getAliceProtocolAddress()))
-      sessionBuilder.process(getAlicePreKeyBundle())
+      sessionBuilder.process(getAlicePreKeyBundle(), UsePqRatchet.NO)
     }
 
     return cipher.encrypt(getAliceProtocolAddress(), getAliceUnidentifiedAccess(), envelopeContent)
@@ -77,7 +78,7 @@ class BobClient(val serviceId: ServiceId, val e164: String, val identityKeyPair:
 
   fun decrypt(envelope: Envelope, serverDeliveredTimestamp: Long) {
     val cipher = SignalServiceCipher(serviceAddress, 1, aciStore, sessionLock, SealedSenderAccessUtil.getCertificateValidator())
-    cipher.decrypt(envelope, serverDeliveredTimestamp)
+    cipher.decrypt(envelope, serverDeliveredTimestamp, UsePqRatchet.NO)
   }
 
   private fun getAliceServiceId(): ServiceId {

app/src/main/java/org/thoughtcrime/securesms/dependencies/ApplicationDependencyProvider.java

@@ -170,7 +170,8 @@ public class ApplicationDependencyProvider implements AppDependencies.Provider {
                                             Optional.of(new SecurityEventListener(context)),
                                             SignalExecutors.newCachedBoundedExecutor("signal-messages", ThreadUtil.PRIORITY_IMPORTANT_BACKGROUND_THREAD, 1, 16, 30),
                                             ByteUnit.KILOBYTES.toBytes(256),
-                                            RemoteConfig::useMessageSendRestFallback);
+                                            RemoteConfig::useMessageSendRestFallback,
+                                            RemoteConfig.usePqRatchet());
   }
 
   @Override

app/src/main/java/org/thoughtcrime/securesms/messages/MessageDecryptor.kt

@@ -142,7 +142,7 @@ object MessageDecryptor {
 
     return try {
       val startTimeNanos = System.nanoTime()
-      val cipherResult: SignalServiceCipherResult? = cipher.decrypt(envelope, serverDeliveredTimestamp)
+      val cipherResult: SignalServiceCipherResult? = cipher.decrypt(envelope, serverDeliveredTimestamp, RemoteConfig.usePqRatchet)
       val endTimeNanos = System.nanoTime()
 
       if (cipherResult == null) {

app/src/main/java/org/thoughtcrime/securesms/util/RemoteConfig.kt

@@ -11,6 +11,7 @@ import org.signal.core.util.gibiBytes
 import org.signal.core.util.kibiBytes
 import org.signal.core.util.logging.Log
 import org.signal.core.util.mebiBytes
+import org.signal.libsignal.protocol.UsePqRatchet
 import org.thoughtcrime.securesms.BuildConfig
 import org.thoughtcrime.securesms.dependencies.AppDependencies
 import org.thoughtcrime.securesms.groups.SelectionLimits
@@ -1154,5 +1155,15 @@ object RemoteConfig {
     durationUnit = DurationUnit.DAYS
   )
 
+  /** Whether or not to use the new post-quantum ratcheting. */
+  @JvmStatic
+  @get:JvmName("usePqRatchet")
+  val usePqRatchet: UsePqRatchet by remoteValue(
+    key = "global.usePqRatchet",
+    hotSwappable = true
+  ) { value ->
+    if (value.asBoolean(false)) UsePqRatchet.YES else UsePqRatchet.NO
+  }
+
   // endregion
 }

libsignal-service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java

@@ -13,6 +13,7 @@ import org.signal.libsignal.protocol.InvalidRegistrationIdException;
 import org.signal.libsignal.protocol.NoSessionException;
 import org.signal.libsignal.protocol.SessionBuilder;
 import org.signal.libsignal.protocol.SignalProtocolAddress;
+import org.signal.libsignal.protocol.UsePqRatchet;
 import org.signal.libsignal.protocol.groups.GroupSessionBuilder;
 import org.signal.libsignal.protocol.logging.Log;
 import org.signal.libsignal.protocol.message.DecryptionErrorMessage;
@@ -182,6 +183,7 @@ public class SignalServiceMessageSender {
   private final Scheduler       scheduler;
   private final long            maxEnvelopeSize;
   private final BooleanSupplier useRestFallback;
+  private final UsePqRatchet usePqRatchet;
 
   public SignalServiceMessageSender(PushServiceSocket pushServiceSocket,
                                     SignalServiceDataStore store,
@@ -192,7 +194,8 @@ public class SignalServiceMessageSender {
                                     Optional<EventListener> eventListener,
                                     ExecutorService executor,
                                     long maxEnvelopeSize,
-                                    BooleanSupplier useRestFallback)
+                                    BooleanSupplier useRestFallback,
+                                    UsePqRatchet usePqRatchet)
   {
     CredentialsProvider credentialsProvider = pushServiceSocket.getCredentialsProvider();
 
@@ -210,6 +213,7 @@ public class SignalServiceMessageSender {
     this.scheduler        = Schedulers.from(executor, false, false);
     this.keysApi          = keysApi;
     this.useRestFallback  = useRestFallback;
+    this.usePqRatchet     = usePqRatchet;
   }
 
   /**
@@ -2701,7 +2705,7 @@ public class SignalServiceMessageSender {
           try {
             SignalProtocolAddress preKeyAddress  = new SignalProtocolAddress(recipient.getIdentifier(), preKey.getDeviceId());
             SignalSessionBuilder  sessionBuilder = new SignalSessionBuilder(sessionLock, new SessionBuilder(aciStore, preKeyAddress));
-            sessionBuilder.process(preKey);
+            sessionBuilder.process(preKey, usePqRatchet);
           } catch (org.signal.libsignal.protocol.UntrustedIdentityException e) {
             throw new UntrustedIdentityException("Untrusted identity key!", recipient.getIdentifier(), preKey.getIdentityKey());
           }
@@ -2753,7 +2757,7 @@ public class SignalServiceMessageSender {
 
         try {
           SignalSessionBuilder sessionBuilder = new SignalSessionBuilder(sessionLock, new SessionBuilder(aciStore, new SignalProtocolAddress(recipient.getIdentifier(), missingDeviceId)));
-          sessionBuilder.process(preKey);
+          sessionBuilder.process(preKey, usePqRatchet);
         } catch (org.signal.libsignal.protocol.UntrustedIdentityException e) {
           throw new UntrustedIdentityException("Untrusted identity key!", recipient.getIdentifier(), preKey.getIdentityKey());
         }

libsignal-service/src/main/java/org/whispersystems/signalservice/api/crypto/SignalServiceCipher.java

@@ -34,6 +34,7 @@ import org.signal.libsignal.protocol.NoSessionException;
 import org.signal.libsignal.protocol.SessionCipher;
 import org.signal.libsignal.protocol.SignalProtocolAddress;
 import org.signal.libsignal.protocol.UntrustedIdentityException;
+import org.signal.libsignal.protocol.UsePqRatchet;
 import org.signal.libsignal.protocol.groups.GroupCipher;
 import org.signal.libsignal.protocol.logging.Log;
 import org.signal.libsignal.protocol.message.CiphertextMessage;
@@ -131,7 +132,7 @@ public class SignalServiceCipher {
     }
   }
 
-  public SignalServiceCipherResult decrypt(Envelope envelope, long serverDeliveredTimestamp)
+  public SignalServiceCipherResult decrypt(Envelope envelope, long serverDeliveredTimestamp, UsePqRatchet usePqRatchet)
       throws InvalidMetadataMessageException, InvalidMetadataVersionException,
              ProtocolInvalidKeyIdException, ProtocolLegacyMessageException,
              ProtocolUntrustedIdentityException, ProtocolNoSessionException,
@@ -141,7 +142,7 @@ public class SignalServiceCipher {
   {
     try {
       if (envelope.content != null) {
-        Plaintext plaintext = decryptInternal(envelope, serverDeliveredTimestamp);
+        Plaintext plaintext = decryptInternal(envelope, serverDeliveredTimestamp, usePqRatchet);
         Content   content   = Content.ADAPTER.decode(plaintext.getData());
 
         return new SignalServiceCipherResult(
@@ -163,7 +164,7 @@ public class SignalServiceCipher {
     }
   }
 
-  private Plaintext decryptInternal(Envelope envelope, long serverDeliveredTimestamp)
+  private Plaintext decryptInternal(Envelope envelope, long serverDeliveredTimestamp, UsePqRatchet usePqRatchet)
       throws InvalidMetadataMessageException, InvalidMetadataVersionException,
       ProtocolDuplicateMessageException, ProtocolUntrustedIdentityException,
       ProtocolLegacyMessageException, ProtocolInvalidKeyException,
@@ -184,7 +185,7 @@ public class SignalServiceCipher {
         SignalProtocolAddress sourceAddress = new SignalProtocolAddress(envelope.sourceServiceId, envelope.sourceDevice);
         SignalSessionCipher   sessionCipher = new SignalSessionCipher(sessionLock, new SessionCipher(signalProtocolStore, sourceAddress));
 
-        paddedMessage = sessionCipher.decrypt(new PreKeySignalMessage(envelope.content.toByteArray()));
+        paddedMessage = sessionCipher.decrypt(new PreKeySignalMessage(envelope.content.toByteArray()), usePqRatchet);
         metadata      = new SignalServiceMetadata(getSourceAddress(envelope), envelope.sourceDevice, envelope.timestamp, envelope.serverTimestamp, serverDeliveredTimestamp, false, envelope.serverGuid, Optional.empty(), envelope.destinationServiceId);
 
         signalProtocolStore.clearSenderKeySharedWith(Collections.singleton(sourceAddress));

libsignal-service/src/main/java/org/whispersystems/signalservice/api/crypto/SignalSessionBuilder.java

@@ -20,9 +20,9 @@ public class SignalSessionBuilder {
     this.builder = builder;
   }
 
-  public void process(PreKeyBundle preKey) throws InvalidKeyException, UntrustedIdentityException {
+  public void process(PreKeyBundle preKey, UsePqRatchet usePqRatchet) throws InvalidKeyException, UntrustedIdentityException {
     try (SignalSessionLock.Lock unused = lock.acquire()) {
-      builder.process(preKey, UsePqRatchet.NO);
+      builder.process(preKey, usePqRatchet);
     }
   }
 }

libsignal-service/src/main/java/org/whispersystems/signalservice/api/crypto/SignalSessionCipher.java

@@ -34,9 +34,9 @@ public class SignalSessionCipher {
     }
   }
 
-  public byte[] decrypt(PreKeySignalMessage ciphertext) throws DuplicateMessageException, LegacyMessageException, InvalidMessageException, InvalidKeyIdException, InvalidKeyException, org.signal.libsignal.protocol.UntrustedIdentityException {
+  public byte[] decrypt(PreKeySignalMessage ciphertext, UsePqRatchet usePqRatchet) throws DuplicateMessageException, LegacyMessageException, InvalidMessageException, InvalidKeyIdException, InvalidKeyException, org.signal.libsignal.protocol.UntrustedIdentityException {
     try (SignalSessionLock.Lock unused = lock.acquire()) {
-      return cipher.decrypt(ciphertext, UsePqRatchet.NO);
+      return cipher.decrypt(ciphertext, usePqRatchet);
     }
   }
 

microbenchmark/src/androidTest/java/org/signal/util/SignalClient.kt

@@ -163,7 +163,7 @@ class SignalClient {
   }
 
   fun decryptMessage(envelope: Envelope) {
-    cipher.decrypt(envelope, System.currentTimeMillis())
+    cipher.decrypt(envelope, System.currentTimeMillis(), UsePqRatchet.NO)
   }
 
   private fun createPreKeyBundle(): PreKeyBundle {