Retire string-based service identifiers/UUIDs in Envelope entities

service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java

@@ -509,7 +509,7 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
     MessagesDynamoDb messagesDynamoDb = new MessagesDynamoDb(dynamoDbClient, dynamoDbAsyncClient,
         config.getDynamoDbTables().getMessages().getTableName(),
         config.getDynamoDbTables().getMessages().getExpiration(),
-        messageDeletionAsyncExecutor, experimentEnrollmentManager);
+        messageDeletionAsyncExecutor);
     RemoteConfigs remoteConfigs = new RemoteConfigs(dynamoDbClient,
         config.getDynamoDbTables().getRemoteConfig().getTableName());
     PushChallengeDynamoDb pushChallengeDynamoDb = new PushChallengeDynamoDb(dynamoDbClient,
@@ -700,7 +700,7 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
     ProfilesManager profilesManager = new ProfilesManager(profilesV1, profiles, cacheCluster, retryExecutor, asyncCdnS3Client,
         config.getCdnConfiguration().bucket());
     MessagesCache messagesCache = new MessagesCache(messagesCluster, messageDeliveryScheduler,
-        messageDeletionAsyncExecutor, retryExecutor, clock, experimentEnrollmentManager);
+        messageDeletionAsyncExecutor, retryExecutor, clock);
     ClientReleaseManager clientReleaseManager = new ClientReleaseManager(clientReleases,
         recurringJobExecutor,
         config.getClientReleaseConfiguration().refreshInterval(),

service/src/main/java/org/whispersystems/textsecuregcm/entities/IncomingMessage.java

@@ -50,7 +50,7 @@ public record IncomingMessage(int type,
         .setType(MessageProtos.Envelope.Type.forNumber(type))
         .setClientTimestamp(timestamp)
         .setServerTimestamp(clock.millis())
-        .setDestinationServiceId(destinationIdentifier.toServiceIdentifierString())
+        .setDestinationServiceId(destinationIdentifier.toCompactByteString())
         .setEphemeral(ephemeral)
         .setUrgent(urgent);
 
@@ -61,7 +61,7 @@ public record IncomingMessage(int type,
 
     if (sourceServiceIdentifier != null && sourceDeviceId != null) {
       envelopeBuilder
-          .setSourceServiceId(sourceServiceIdentifier.toServiceIdentifierString())
+          .setSourceServiceId(sourceServiceIdentifier.toCompactByteString())
           .setSourceDevice(sourceDeviceId.intValue());
     }
 

service/src/main/java/org/whispersystems/textsecuregcm/grpc/AccountsAnonymousGrpcService.java

@@ -38,7 +38,7 @@ public class AccountsAnonymousGrpcService extends SimpleAccountsAnonymousGrpc.Ac
       throws RateLimitExceededException {
 
     final ServiceIdentifier serviceIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getServiceIdentifier());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getServiceIdentifier());
 
     RateLimitUtil.rateLimitByRemoteAddress(rateLimiters.getCheckAccountExistenceLimiter());
 
@@ -55,7 +55,7 @@ public class AccountsAnonymousGrpcService extends SimpleAccountsAnonymousGrpc.Ac
 
     return accountsManager.getByUsernameHash(request.getUsernameHash().toByteArray()).join()
         .map(account -> LookupUsernameHashResponse.newBuilder()
-            .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(account.getUuid())))
+            .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(account.getUuid())))
             .build())
         .orElseGet(() -> LookupUsernameHashResponse.newBuilder().setNotFound(NotFound.getDefaultInstance()).build());
   }

service/src/main/java/org/whispersystems/textsecuregcm/grpc/AccountsGrpcService.java

@@ -13,7 +13,6 @@ import java.util.HexFormat;
 import java.util.List;
 import java.util.Objects;
 import java.util.UUID;
-import java.util.concurrent.ThreadLocalRandom;
 import org.signal.chat.account.ClearRegistrationLockRequest;
 import org.signal.chat.account.ClearRegistrationLockResponse;
 import org.signal.chat.account.ConfigureUnidentifiedAccessRequest;
@@ -88,8 +87,8 @@ public class AccountsGrpcService extends SimpleAccountsGrpc.AccountsImplBase {
     final Account account = getAuthenticatedAccount();
 
     final AccountIdentifiers.Builder accountIdentifiersBuilder = AccountIdentifiers.newBuilder()
-        .addServiceIdentifiers(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(account.getUuid())))
-        .addServiceIdentifiers(ServiceIdentifierUtil.toGrpcServiceIdentifier(new PniServiceIdentifier(account.getPhoneNumberIdentifier())))
+        .addServiceIdentifiers(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(account.getUuid())))
+        .addServiceIdentifiers(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new PniServiceIdentifier(account.getPhoneNumberIdentifier())))
         .setE164(account.getNumber());
 
     account.getUsernameHash().ifPresent(usernameHash ->

service/src/main/java/org/whispersystems/textsecuregcm/grpc/GrpcServiceIdentifierUtil.java

@@ -5,17 +5,15 @@
 
 package org.whispersystems.textsecuregcm.grpc;
 
-import com.google.protobuf.ByteString;
-import io.grpc.Status;
 import java.util.UUID;
 import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.identity.PniServiceIdentifier;
 import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
 import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
-public class ServiceIdentifierUtil {
+public class GrpcServiceIdentifierUtil {
 
-  private ServiceIdentifierUtil() {
+  private GrpcServiceIdentifierUtil() {
   }
 
   public static ServiceIdentifier fromGrpcServiceIdentifier(final org.signal.chat.common.ServiceIdentifier serviceIdentifier) {
@@ -42,12 +40,4 @@ public class ServiceIdentifierUtil {
         .setUuid(UUIDUtil.toByteString(serviceIdentifier.uuid()))
         .build();
   }
-
-  public static ByteString toCompactByteString(final ServiceIdentifier serviceIdentifier) {
-    return ByteString.copyFrom(serviceIdentifier.toCompactByteArray());
-  }
-
-  public static ServiceIdentifier fromByteString(final ByteString byteString) {
-    return ServiceIdentifier.fromBytes(byteString.toByteArray());
-  }
 }

service/src/main/java/org/whispersystems/textsecuregcm/grpc/KeysAnonymousGrpcService.java

@@ -13,7 +13,6 @@ import java.util.Arrays;
 import java.util.concurrent.Flow;
 import org.signal.chat.errors.FailedUnidentifiedAuthorization;
 import org.signal.chat.errors.NotFound;
-import org.signal.chat.keys.AccountPreKeyBundles;
 import org.signal.chat.keys.CheckIdentityKeyRequest;
 import org.signal.chat.keys.CheckIdentityKeyResponse;
 import org.signal.chat.keys.GetPreKeysAnonymousRequest;
@@ -46,7 +45,7 @@ public class KeysAnonymousGrpcService extends SimpleKeysAnonymousGrpc.KeysAnonym
   @Override
   public GetPreKeysAnonymousResponse getPreKeys(final GetPreKeysAnonymousRequest request) {
     final ServiceIdentifier serviceIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getTargetIdentifier());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getTargetIdentifier());
 
     final byte deviceId = request.getRequest().hasDeviceId()
         ? DeviceIdUtil.validate(request.getRequest().getDeviceId())
@@ -91,7 +90,7 @@ public class KeysAnonymousGrpcService extends SimpleKeysAnonymousGrpc.KeysAnonym
   @Override
   public Flow.Publisher<CheckIdentityKeyResponse> checkIdentityKeys(final Flow.Publisher<CheckIdentityKeyRequest> requests) {
     return JdkFlowAdapter.publisherToFlowPublisher(JdkFlowAdapter.flowPublisherToFlux(requests)
-        .map(request -> Tuples.of(ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getTargetIdentifier()),
+        .map(request -> Tuples.of(GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getTargetIdentifier()),
             request.getFingerprint().toByteArray()))
         .flatMap(serviceIdentifierAndFingerprint -> Mono.fromFuture(
                 () -> accountsManager.getByServiceIdentifierAsync(serviceIdentifierAndFingerprint.getT1()))
@@ -100,7 +99,7 @@ public class KeysAnonymousGrpcService extends SimpleKeysAnonymousGrpc.KeysAnonym
                 .identityType()), serviceIdentifierAndFingerprint.getT2()))
             .map(account -> CheckIdentityKeyResponse.newBuilder()
                 .setTargetIdentifier(
-                    ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifierAndFingerprint.getT1()))
+                    GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifierAndFingerprint.getT1()))
                 .setIdentityKey(ByteString.copyFrom(account.getIdentityKey(serviceIdentifierAndFingerprint.getT1()
                     .identityType()).serialize()))
                 .build())));

service/src/main/java/org/whispersystems/textsecuregcm/grpc/KeysGrpcService.java

@@ -96,7 +96,7 @@ public class KeysGrpcService extends SimpleKeysGrpc.KeysImplBase {
     final AuthenticatedDevice authenticatedDevice = AuthenticationUtil.requireAuthenticatedDevice();
 
     final ServiceIdentifier targetIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getTargetIdentifier());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getTargetIdentifier());
 
 
     final Optional<Account> maybeTargetAccount = accountsManager.getByServiceIdentifier(targetIdentifier);

service/src/main/java/org/whispersystems/textsecuregcm/grpc/MessagesAnonymousGrpcService.java

@@ -6,19 +6,18 @@
 package org.whispersystems.textsecuregcm.grpc;
 
 import com.google.protobuf.ByteString;
+import com.google.protobuf.Empty;
 import java.time.Clock;
 import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
-import com.google.protobuf.Empty;
-import io.grpc.Status;
 import org.signal.chat.errors.FailedUnidentifiedAuthorization;
 import org.signal.chat.errors.NotFound;
 import org.signal.chat.messages.IndividualRecipientMessageBundle;
-import org.signal.chat.messages.SendMessageType;
 import org.signal.chat.messages.MultiRecipientMismatchedDevices;
 import org.signal.chat.messages.MultiRecipientSuccess;
 import org.signal.chat.messages.SendMessageResponse;
+import org.signal.chat.messages.SendMessageType;
 import org.signal.chat.messages.SendMultiRecipientMessageRequest;
 import org.signal.chat.messages.SendMultiRecipientMessageResponse;
 import org.signal.chat.messages.SendMultiRecipientStoryRequest;
@@ -85,7 +84,7 @@ public class MessagesAnonymousGrpcService extends SimpleMessagesAnonymousGrpc.Me
       throws RateLimitExceededException {
 
     final ServiceIdentifier destinationServiceIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getDestination());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getDestination());
 
     final Optional<Account> maybeDestination = accountsManager.getByServiceIdentifier(destinationServiceIdentifier);
 
@@ -133,7 +132,7 @@ public class MessagesAnonymousGrpcService extends SimpleMessagesAnonymousGrpc.Me
       throws RateLimitExceededException {
 
     final ServiceIdentifier destinationServiceIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getDestination());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getDestination());
 
     final Optional<Account> maybeDestination = accountsManager.getByServiceIdentifier(destinationServiceIdentifier);
 
@@ -194,7 +193,7 @@ public class MessagesAnonymousGrpcService extends SimpleMessagesAnonymousGrpc.Me
                   .setType(MessageProtos.Envelope.Type.UNIDENTIFIED_SENDER)
                   .setClientTimestamp(messages.getTimestamp())
                   .setServerTimestamp(clock.millis())
-                  .setDestinationServiceId(destinationServiceIdentifier.toServiceIdentifierString())
+                  .setDestinationServiceId(destinationServiceIdentifier.toCompactByteString())
                   .setEphemeral(ephemeral)
                   .setUrgent(urgent)
                   .setContent(entry.getValue().getPayload());
@@ -313,7 +312,7 @@ public class MessagesAnonymousGrpcService extends SimpleMessagesAnonymousGrpc.Me
       final MultiRecipientSuccess.Builder responseBuilder = MultiRecipientSuccess.newBuilder();
 
       MessageUtil.getUnresolvedRecipients(multiRecipientMessage, resolvedRecipients).stream()
-          .map(ServiceIdentifierUtil::toGrpcServiceIdentifier)
+          .map(GrpcServiceIdentifierUtil::toGrpcServiceIdentifier)
           .forEach(responseBuilder::addUnresolvedRecipients);
 
       return SendMultiRecipientMessageResponse.newBuilder().setSuccess(responseBuilder).build();

service/src/main/java/org/whispersystems/textsecuregcm/grpc/MessagesGrpcHelper.java

@@ -23,7 +23,7 @@ public class MessagesGrpcHelper {
       final org.whispersystems.textsecuregcm.controllers.MismatchedDevices mismatchedDevices) {
 
     final MismatchedDevices.Builder mismatchedDevicesBuilder = MismatchedDevices.newBuilder()
-        .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier));
+        .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier));
 
     mismatchedDevices.missingDeviceIds().forEach(mismatchedDevicesBuilder::addMissingDevices);
     mismatchedDevices.extraDeviceIds().forEach(mismatchedDevicesBuilder::addExtraDevices);

service/src/main/java/org/whispersystems/textsecuregcm/grpc/MessagesGrpcService.java

@@ -76,7 +76,7 @@ public class MessagesGrpcService extends SimpleMessagesGrpc.MessagesImplBase {
         .orElseThrow(() -> GrpcExceptions.invalidCredentials("invalid credentials"));
 
     final ServiceIdentifier destinationServiceIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getDestination());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getDestination());
 
     if (sender.isIdentifiedBy(destinationServiceIdentifier)) {
       throw GrpcExceptions.invalidArguments("use `sendSyncMessage` to send messages to own account");
@@ -159,8 +159,8 @@ public class MessagesGrpcService extends SimpleMessagesGrpc.MessagesImplBase {
                   .setType(getEnvelopeType(entry.getValue().getType()))
                   .setClientTimestamp(messages.getTimestamp())
                   .setServerTimestamp(clock.millis())
-                  .setDestinationServiceId(destinationServiceIdentifier.toServiceIdentifierString())
-                  .setSourceServiceId(new AciServiceIdentifier(sender.accountIdentifier()).toServiceIdentifierString())
+                  .setDestinationServiceId(destinationServiceIdentifier.toCompactByteString())
+                  .setSourceServiceId(new AciServiceIdentifier(sender.accountIdentifier()).toCompactByteString())
                   .setSourceDevice(sender.deviceId())
                   .setEphemeral(ephemeral)
                   .setUrgent(urgent)

service/src/main/java/org/whispersystems/textsecuregcm/grpc/ProfileAnonymousGrpcService.java

@@ -63,7 +63,7 @@ public class ProfileAnonymousGrpcService extends SimpleProfileAnonymousGrpc.Prof
   @Override
   public GetUnversionedProfileAnonymousResponse getUnversionedProfile(final GetUnversionedProfileAnonymousRequest request) {
     final ServiceIdentifier targetIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getServiceIdentifier());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getServiceIdentifier());
 
     // Callers must be authenticated to request unversioned profiles by PNI
     if (targetIdentifier.identityType() == IdentityType.PNI) {
@@ -100,7 +100,7 @@ public class ProfileAnonymousGrpcService extends SimpleProfileAnonymousGrpc.Prof
 
   @Override
   public GetVersionedProfileAnonymousResponse getVersionedProfile(final GetVersionedProfileAnonymousRequest request) {
-    final ServiceIdentifier targetIdentifier = ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getAccountIdentifier());
+    final ServiceIdentifier targetIdentifier = GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getAccountIdentifier());
 
     final Optional<Account> targetAccount = getTargetAccountAndValidateUnidentifiedAccess(targetIdentifier, request.getUnidentifiedAccessKey().toByteArray());
 
@@ -123,7 +123,7 @@ public class ProfileAnonymousGrpcService extends SimpleProfileAnonymousGrpc.Prof
   @Override
   public GetExpiringProfileKeyCredentialAnonymousResponse getExpiringProfileKeyCredential(
       final GetExpiringProfileKeyCredentialAnonymousRequest request) {
-    final ServiceIdentifier targetIdentifier = ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getAccountIdentifier());
+    final ServiceIdentifier targetIdentifier = GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getRequest().getAccountIdentifier());
 
     if (request.getRequest().getCredentialType() != CredentialType.CREDENTIAL_TYPE_EXPIRING_PROFILE_KEY) {
       throw GrpcExceptions.constraintViolation("invalid credential type");

service/src/main/java/org/whispersystems/textsecuregcm/grpc/ProfileGrpcService.java

@@ -211,7 +211,7 @@ public class ProfileGrpcService extends SimpleProfileGrpc.ProfileImplBase {
   public GetUnversionedProfileResponse getUnversionedProfile(final GetUnversionedProfileRequest request) throws RateLimitExceededException {
     final AuthenticatedDevice authenticatedDevice = AuthenticationUtil.requireAuthenticatedDevice();
     final ServiceIdentifier targetIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getServiceIdentifier());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getServiceIdentifier());
     final Optional<Account> maybeAccount = validateRateLimitAndGetAccount(authenticatedDevice.accountIdentifier(), targetIdentifier);
 
     return maybeAccount.map(account -> GetUnversionedProfileResponse.newBuilder()
@@ -228,7 +228,7 @@ public class ProfileGrpcService extends SimpleProfileGrpc.ProfileImplBase {
   public GetVersionedProfileResponse getVersionedProfile(final GetVersionedProfileRequest request) throws RateLimitExceededException {
     final AuthenticatedDevice authenticatedDevice = AuthenticationUtil.requireAuthenticatedDevice();
     final ServiceIdentifier targetIdentifier =
-        ServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getAccountIdentifier());
+        GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(request.getAccountIdentifier());
 
     final Optional<Account> maybeAccount = validateRateLimitAndGetAccount(authenticatedDevice.accountIdentifier(), targetIdentifier);
 

service/src/main/java/org/whispersystems/textsecuregcm/identity/AciServiceIdentifier.java

@@ -5,6 +5,7 @@
 
 package org.whispersystems.textsecuregcm.identity;
 
+import com.google.protobuf.ByteString;
 import io.micrometer.core.instrument.Metrics;
 import io.swagger.v3.oas.annotations.media.Schema;
 import java.nio.ByteBuffer;
@@ -62,6 +63,10 @@ public record AciServiceIdentifier(UUID uuid) implements ServiceIdentifier {
     return new AciServiceIdentifier(UUID.fromString(string));
   }
 
+  public static AciServiceIdentifier fromByteString(final ByteString byteString) {
+    return fromBytes(byteString.toByteArray());
+  }
+
   public static AciServiceIdentifier fromBytes(final byte[] bytes) {
     final UUID uuid;
 

service/src/main/java/org/whispersystems/textsecuregcm/identity/ServiceIdentifier.java

@@ -5,6 +5,7 @@
 
 package org.whispersystems.textsecuregcm.identity;
 
+import com.google.protobuf.ByteString;
 import io.swagger.v3.oas.annotations.media.Schema;
 import java.util.UUID;
 import org.signal.libsignal.protocol.ServiceId;
@@ -49,6 +50,15 @@ public sealed interface ServiceIdentifier permits AciServiceIdentifier, PniServi
    */
   byte[] toCompactByteArray();
 
+  /**
+   * Returns a compact binary representation of this account identifier as a {@link ByteString}.
+   *
+   * @return a binary representation of this account identifier
+   */
+  default ByteString toCompactByteString() {
+    return ByteString.copyFrom(toCompactByteArray());
+  }
+
   /**
    * Returns a fixed-width binary representation of this account identifier.
    *
@@ -56,11 +66,20 @@ public sealed interface ServiceIdentifier permits AciServiceIdentifier, PniServi
    */
   byte[] toFixedWidthByteArray();
 
+  /**
+   * Returns a fixed-width binary representation of this account identifier as a {@link ByteString}.
+   *
+   * @return a binary representation of this account identifier
+   */
+  default ByteString toFixedWidthByteString() {
+    return ByteString.copyFrom(toFixedWidthByteArray());
+  }
+
   /**
    * Parse a service identifier string, which should be a plain UUID string for ACIs and a prefixed UUID string for PNIs
    *
-   * @param string A service identifier string
-   * @return The parsed {@link ServiceIdentifier}
+   * @param string a service identifier string
+   * @return the parsed service identifier
    */
   static ServiceIdentifier valueOf(final String string) {
     try {
@@ -70,6 +89,12 @@ public sealed interface ServiceIdentifier permits AciServiceIdentifier, PniServi
     }
   }
 
+  /**
+   * Parse a service identifier from a byte array.
+   *
+   * @param bytes the byte array from which to parse a service identifier
+   * @return the parsed service identifier
+   */
   static ServiceIdentifier fromBytes(final byte[] bytes) {
     try {
       return AciServiceIdentifier.fromBytes(bytes);
@@ -78,6 +103,16 @@ public sealed interface ServiceIdentifier permits AciServiceIdentifier, PniServi
     }
   }
 
+  /**
+   * Parse a service identifier from a byte string.
+   *
+   * @param byteString the byte string from which to parse a service identifier
+   * @return the parsed service identifier
+   */
+  static ServiceIdentifier fromByteString(final ByteString byteString) {
+    return fromBytes(byteString.toByteArray());
+  }
+
   static ServiceIdentifier fromLibsignal(final ServiceId libsignalServiceId) {
     if (libsignalServiceId instanceof ServiceId.Aci) {
       return new AciServiceIdentifier(libsignalServiceId.getRawUUID());

service/src/main/java/org/whispersystems/textsecuregcm/metrics/MessageMetrics.java

@@ -15,6 +15,7 @@ import io.micrometer.core.instrument.Timer;
 import java.time.Duration;
 import java.time.Instant;
 import java.util.ArrayList;
+import java.util.HexFormat;
 import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -46,9 +47,10 @@ public final class MessageMetrics {
       final MessageProtos.Envelope envelope) {
     if (envelope.hasDestinationServiceId()) {
       try {
-        measureAccountDestinationUuidMismatches(account, ServiceIdentifier.valueOf(envelope.getDestinationServiceId()));
+        measureAccountDestinationUuidMismatches(account, ServiceIdentifier.fromByteString(envelope.getDestinationServiceId()));
       } catch (final IllegalArgumentException ignored) {
-        logger.warn("Envelope had invalid destination UUID: {}", envelope.getDestinationServiceId());
+        logger.warn("Envelope had invalid destination service ID: {}",
+            HexFormat.of().formatHex(envelope.getDestinationServiceId().toByteArray()));
       }
     }
   }

service/src/main/java/org/whispersystems/textsecuregcm/push/MessageSender.java

@@ -4,8 +4,8 @@
  */
 package org.whispersystems.textsecuregcm.push;
 
-import static org.whispersystems.textsecuregcm.metrics.MetricsUtil.name;
 import static org.whispersystems.textsecuregcm.entities.MessageProtos.Envelope;
+import static org.whispersystems.textsecuregcm.metrics.MetricsUtil.name;
 
 import com.google.common.annotations.VisibleForTesting;
 import io.dropwizard.util.DataSize;
@@ -24,7 +24,6 @@ import java.util.concurrent.CompletableFuture;
 import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 import kotlin.Pair;
-import org.apache.commons.lang3.StringUtils;
 import org.signal.libsignal.protocol.SealedSenderMultiRecipientMessage;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfiguration;
 import org.whispersystems.textsecuregcm.controllers.MessageDeliveryNotAllowedException;
@@ -327,15 +326,15 @@ public class MessageSender {
 
     final byte excludedDeviceId;
     if (syncMessageSenderDeviceId.isPresent()) {
-      if (messagesByDeviceId.values().stream().anyMatch(message -> StringUtils.isBlank(message.getSourceServiceId()) ||
-          !destination.isIdentifiedBy(ServiceIdentifier.valueOf(message.getSourceServiceId())))) {
+      if (messagesByDeviceId.values().stream().anyMatch(message -> !message.hasSourceServiceId() ||
+          !destination.isIdentifiedBy(ServiceIdentifier.fromByteString(message.getSourceServiceId())))) {
 
         throw new IllegalArgumentException("Sync message sender device ID specified, but one or more messages are not addressed to sender");
       }
       excludedDeviceId = syncMessageSenderDeviceId.get();
     } else {
-      if (messagesByDeviceId.values().stream().anyMatch(message -> StringUtils.isNotBlank(message.getSourceServiceId()) &&
-          destination.isIdentifiedBy(ServiceIdentifier.valueOf(message.getSourceServiceId())))) {
+      if (messagesByDeviceId.values().stream().anyMatch(message -> message.hasSourceServiceId() &&
+          destination.isIdentifiedBy(ServiceIdentifier.fromByteString(message.getSourceServiceId())))) {
 
         throw new IllegalArgumentException("Sync message sender device ID not specified, but one or more messages are addressed to sender");
       }

service/src/main/java/org/whispersystems/textsecuregcm/push/ReceiptSender.java

@@ -44,9 +44,9 @@ public class ReceiptSender {
             destinationAccount -> {
               final Envelope message = Envelope.newBuilder()
                   .setServerTimestamp(System.currentTimeMillis())
-                  .setSourceServiceId(sourceIdentifier.toServiceIdentifierString())
+                  .setSourceServiceId(sourceIdentifier.toCompactByteString())
                   .setSourceDevice(sourceDeviceId)
-                  .setDestinationServiceId(destinationIdentifier.toServiceIdentifierString())
+                  .setDestinationServiceId(destinationIdentifier.toCompactByteString())
                   .setClientTimestamp(messageId)
                   .setType(Envelope.Type.SERVER_DELIVERY_RECEIPT)
                   .setUrgent(false)

service/src/main/java/org/whispersystems/textsecuregcm/storage/ChangeNumberManager.java

@@ -40,6 +40,7 @@ import org.whispersystems.textsecuregcm.metrics.UserAgentTagUtil;
 import org.whispersystems.textsecuregcm.push.MessageSender;
 import org.whispersystems.textsecuregcm.push.MessageTooLargeException;
 import org.whispersystems.textsecuregcm.util.Pair;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 public class ChangeNumberManager {
 
@@ -159,10 +160,9 @@ public class ChangeNumberManager {
 
     try {
       // Now that we've actually updated the account, populate the "updated PNI" field on all envelopes
-      final String updatedPniString = updatedAccount.getIdentifier(IdentityType.PNI).toString();
-
       messagesByDeviceId.replaceAll((_, envelope) ->
-          envelope.toBuilder().setUpdatedPni(updatedPniString).build());
+          envelope.toBuilder().setUpdatedPni(UUIDUtil.toByteString(updatedAccount.getIdentifier(IdentityType.PNI)))
+              .build());
 
       messageSender.sendMessages(updatedAccount,
           serviceIdentifier,

service/src/main/java/org/whispersystems/textsecuregcm/storage/EnvelopeUtil.java

@@ -1,135 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.whispersystems.textsecuregcm.storage;
-
-import java.util.UUID;
-import com.google.common.annotations.VisibleForTesting;
-import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
-import org.whispersystems.textsecuregcm.grpc.ServiceIdentifierUtil;
-import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
-import org.whispersystems.textsecuregcm.util.UUIDUtil;
-
-/**
- * Provides utility methods for "compressing" and "expanding" envelopes. Historically UUID-like fields in envelopes have
- * been represented as strings (e.g. "c15f1dfb-ae2c-43a8-9bb9-baba97ac416c"), but <em>could</em> be represented as more
- * compact byte arrays instead. Existing clients generally expect string representations (though that should change in
- * the near future), but we can use the more compressed forms at rest for more efficient storage and transfer.
- */
-public class EnvelopeUtil {
-
-  @VisibleForTesting
-  static final String INCLUDE_BINARY_SERVICE_ID_EXPERIMENT_NAME = "envelopeIncludeBinaryServiceIdentifier";
-
-  /**
-   * Converts all "compressible" UUID-like fields in the given envelope to more compact binary representations.
-   *
-   * @param envelope the envelope to compress
-   *
-   * @return an envelope with string-based UUID-like fields compressed to binary representations
-   */
-  public static MessageProtos.Envelope compress(final MessageProtos.Envelope envelope) {
-    final MessageProtos.Envelope.Builder builder = envelope.toBuilder();
-    
-    if (builder.hasSourceServiceId()) {
-      final ServiceIdentifier sourceServiceId = ServiceIdentifier.valueOf(builder.getSourceServiceId());
-      
-      builder.setSourceServiceIdBinary(ServiceIdentifierUtil.toCompactByteString(sourceServiceId));
-      builder.clearSourceServiceId();
-    }
-
-    if (builder.hasDestinationServiceId()) {
-      final ServiceIdentifier destinationServiceId = ServiceIdentifier.valueOf(builder.getDestinationServiceId());
-
-      builder.setDestinationServiceIdBinary(ServiceIdentifierUtil.toCompactByteString(destinationServiceId));
-      builder.clearDestinationServiceId();
-    }
-
-    if (builder.hasServerGuid()) {
-      final UUID serverGuid = UUID.fromString(builder.getServerGuid());
-
-      builder.setServerGuidBinary(UUIDUtil.toByteString(serverGuid));
-      builder.clearServerGuid();
-    }
-
-    if (builder.hasUpdatedPni()) {
-      final UUID updatedPni = UUID.fromString(builder.getUpdatedPni());
-
-      builder.setUpdatedPniBinary(UUIDUtil.toByteString(updatedPni));
-      builder.clearUpdatedPni();
-    }
-
-    return builder.build();
-  }
-
-  /**
-   * "Expands" all binary representations of UUID-like fields to string representations to meet current client
-   * expectations.
-   *
-   * @param envelope the envelope to expand
-   *
-   * @return an envelope with binary representations of UUID-like fields expanded to string representations
-   */
-  public static MessageProtos.Envelope expand(final MessageProtos.Envelope envelope,
-      final ExperimentEnrollmentManager experimentEnrollmentManager) {
-
-    final boolean includeBinaryServiceIdentifiers;
-
-    if (envelope.hasDestinationServiceIdBinary() || envelope.hasDestinationServiceId()) {
-      final ServiceIdentifier destinationIdentifier = envelope.hasDestinationServiceIdBinary()
-          ? ServiceIdentifier.fromBytes(envelope.getDestinationServiceIdBinary().toByteArray())
-          : ServiceIdentifier.valueOf(envelope.getDestinationServiceId());
-
-      includeBinaryServiceIdentifiers =
-          experimentEnrollmentManager.isEnrolled(destinationIdentifier.uuid(), INCLUDE_BINARY_SERVICE_ID_EXPERIMENT_NAME);
-    } else {
-      includeBinaryServiceIdentifiers = false;
-    }
-
-    final MessageProtos.Envelope.Builder builder = envelope.toBuilder();
-
-    if (builder.hasSourceServiceIdBinary()) {
-      final ServiceIdentifier sourceServiceId =
-          ServiceIdentifierUtil.fromByteString(builder.getSourceServiceIdBinary());
-
-      builder.setSourceServiceId(sourceServiceId.toServiceIdentifierString());
-
-      if (!includeBinaryServiceIdentifiers) {
-        builder.clearSourceServiceIdBinary();
-      }
-    }
-
-    if (builder.hasDestinationServiceIdBinary()) {
-      final ServiceIdentifier destinationServiceId =
-          ServiceIdentifierUtil.fromByteString(builder.getDestinationServiceIdBinary());
-
-      builder.setDestinationServiceId(destinationServiceId.toServiceIdentifierString());
-
-      if (!includeBinaryServiceIdentifiers) {
-        builder.clearDestinationServiceIdBinary();
-      }
-    }
-
-    if (builder.hasServerGuidBinary()) {
-      final UUID serverGuid = UUIDUtil.fromByteString(builder.getServerGuidBinary());
-      
-      builder.setServerGuid(serverGuid.toString());
-
-      if (!includeBinaryServiceIdentifiers) {
-        builder.clearServerGuidBinary();
-      }
-    }
-
-    if (builder.hasUpdatedPniBinary()) {
-      final UUID updatedPni = UUIDUtil.fromByteString(builder.getUpdatedPniBinary());
-
-      // Note that expanded envelopes include BOTH forms of the `updatedPni` field
-      builder.setUpdatedPni(updatedPni.toString());
-    }
-
-    return builder.build();
-  }
-}

service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagePersister.java

@@ -32,6 +32,7 @@ import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfigurati
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.identity.IdentityType;
 import org.whispersystems.textsecuregcm.metrics.DevicePlatformUtil;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import org.whispersystems.textsecuregcm.util.Util;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -366,7 +367,7 @@ public class MessagePersister implements Managed {
                 TRIMMED_MESSAGE_BYTES_COUNTER.increment(envelope.getSerializedSize());
                 return Mono
                     .fromCompletionStage(() -> messagesManager
-                        .delete(aci, device, UUID.fromString(envelope.getServerGuid()), envelope.getServerTimestamp()))
+                        .delete(aci, device, UUIDUtil.fromByteString(envelope.getServerGuid()), envelope.getServerTimestamp()))
                     .retryWhen(retryBackoffSpec)
                     .map(Optional::isPresent);
               })

service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesCache.java

@@ -48,12 +48,12 @@ import org.signal.libsignal.protocol.ServiceId;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
 import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
 import org.whispersystems.textsecuregcm.metrics.MetricsUtil;
 import org.whispersystems.textsecuregcm.redis.FaultTolerantRedisClusterClient;
 import org.whispersystems.textsecuregcm.util.Pair;
 import org.whispersystems.textsecuregcm.util.ResilienceUtil;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.observability.micrometer.Micrometer;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -121,7 +121,6 @@ public class MessagesCache {
   private final ExecutorService messageDeletionExecutorService;
   // messageDeletionExecutorService wrapped into a reactor Scheduler
   private final Scheduler messageDeletionScheduler;
-  private final ExperimentEnrollmentManager experimentEnrollmentManager;
 
   private final MessagesCacheInsertScript insertScript;
   private final MessagesCacheInsertSharedMultiRecipientPayloadAndViewsScript insertMrmScript;
@@ -175,16 +174,13 @@ public class MessagesCache {
       final Scheduler messageDeliveryScheduler,
       final ExecutorService messageDeletionExecutorService,
       final ScheduledExecutorService retryExecutor,
-      final Clock clock,
-      final ExperimentEnrollmentManager experimentEnrollmentManager)
-      throws IOException {
+      final Clock clock) throws IOException {
 
     this(
         redisCluster,
         messageDeliveryScheduler,
         messageDeletionExecutorService,
         clock,
-        experimentEnrollmentManager,
         new MessagesCacheInsertScript(redisCluster, retryExecutor),
         new MessagesCacheInsertSharedMultiRecipientPayloadAndViewsScript(redisCluster, retryExecutor),
         new MessagesCacheGetItemsScript(redisCluster),
@@ -200,7 +196,6 @@ public class MessagesCache {
   MessagesCache(final FaultTolerantRedisClusterClient redisCluster,
                 final Scheduler messageDeliveryScheduler,
                 final ExecutorService messageDeletionExecutorService, final Clock clock,
-                final ExperimentEnrollmentManager experimentEnrollmentManager,
                 final MessagesCacheInsertScript insertScript,
                 final MessagesCacheInsertSharedMultiRecipientPayloadAndViewsScript insertMrmScript,
                 final MessagesCacheGetItemsScript getItemsScript,
@@ -216,7 +211,6 @@ public class MessagesCache {
     this.messageDeliveryScheduler = messageDeliveryScheduler;
     this.messageDeletionExecutorService = messageDeletionExecutorService;
     this.messageDeletionScheduler = Schedulers.fromExecutorService(messageDeletionExecutorService, "messageDeletion");
-    this.experimentEnrollmentManager = experimentEnrollmentManager;
 
     this.insertScript = insertScript;
     this.insertMrmScript = insertMrmScript;
@@ -233,7 +227,7 @@ public class MessagesCache {
       final byte destinationDeviceId,
       final MessageProtos.Envelope message) {
 
-    final MessageProtos.Envelope messageWithGuid = message.toBuilder().setServerGuid(messageGuid.toString()).build();
+    final MessageProtos.Envelope messageWithGuid = message.toBuilder().setServerGuid(UUIDUtil.toByteString(messageGuid)).build();
     final Timer.Sample sample = Timer.start();
 
     return insertScript.executeAsync(destinationAccountIdentifier, destinationDeviceId, messageWithGuid)
@@ -278,7 +272,7 @@ public class MessagesCache {
               removedMessages.add(RemovedMessage.fromEnvelope(envelope));
               if (envelope.hasSharedMrmKey()) {
                 serviceIdentifierToMrmKeys.computeIfAbsent(
-                        ServiceIdentifier.valueOf(envelope.getDestinationServiceId()), _ -> new ArrayList<>())
+                        ServiceIdentifier.fromByteString(envelope.getDestinationServiceId()), _ -> new ArrayList<>())
                     .add(envelope.getSharedMrmKey().toByteArray());
               }
             } catch (final InvalidProtocolBufferException e) {
@@ -398,7 +392,7 @@ public class MessagesCache {
   private void discardStaleMessages(final UUID destinationUuid, final byte destinationDevice,
       Flux<MessageProtos.Envelope> staleMessages, final Counter counter, final String context) {
     staleMessages
-        .map(e -> UUID.fromString(e.getServerGuid()))
+        .map(e -> UUIDUtil.fromByteString(e.getServerGuid()))
         .buffer(PAGE_SIZE)
         .subscribeOn(messageDeletionScheduler)
         .subscribe(messageGuids ->
@@ -479,7 +473,7 @@ public class MessagesCache {
     final byte[] key = mrmMessage.getSharedMrmKey().toByteArray();
     final byte[] sharedMrmViewKey = MessagesCache.getSharedMrmViewKey(
         // the message might be addressed to the account's PNI, so use the service ID from the envelope
-        ServiceIdentifier.valueOf(mrmMessage.getDestinationServiceId()), destinationDevice);
+        ServiceIdentifier.fromByteString(mrmMessage.getDestinationServiceId()), destinationDevice);
 
     return Mono.from(redisCluster.withBinaryCluster(
             conn -> conn.reactive().hmget(key, "data".getBytes(StandardCharsets.UTF_8), sharedMrmViewKey)
@@ -670,10 +664,10 @@ public class MessagesCache {
             try {
               final MessageProtos.Envelope message = parseEnvelope(serialized);
 
-              processedMessages.add(message.getServerGuid());
+              processedMessages.add(UUIDUtil.fromByteString(message.getServerGuid()).toString());
 
               if (message.hasSharedMrmKey()) {
-                serviceIdentifierToMrmKeys.computeIfAbsent(ServiceIdentifier.valueOf(message.getDestinationServiceId()),
+                serviceIdentifierToMrmKeys.computeIfAbsent(ServiceIdentifier.fromByteString(message.getDestinationServiceId()),
                         _ -> new ArrayList<>())
                     .add(message.getSharedMrmKey().toByteArray());
               }
@@ -782,6 +776,6 @@ public class MessagesCache {
   private MessageProtos.Envelope parseEnvelope(final byte[] envelopeBytes)
       throws InvalidProtocolBufferException {
 
-    return EnvelopeUtil.expand(MessageProtos.Envelope.parseFrom(envelopeBytes), experimentEnrollmentManager);
+    return MessageProtos.Envelope.parseFrom(envelopeBytes);
   }
 }

service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesCacheInsertScript.java

@@ -21,6 +21,7 @@ import org.whispersystems.textsecuregcm.push.RedisMessageAvailabilityManager;
 import org.whispersystems.textsecuregcm.redis.ClusterLuaScript;
 import org.whispersystems.textsecuregcm.redis.FaultTolerantRedisClusterClient;
 import org.whispersystems.textsecuregcm.util.ResilienceUtil;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 /**
  * Inserts an envelope into the message queue for a destination device and publishes a "new message available" event.
@@ -62,8 +63,8 @@ class MessagesCacheInsertScript {
     );
 
     final List<byte[]> args = new ArrayList<>(Arrays.asList(
-        EnvelopeUtil.compress(envelope).toByteArray(), // message
-        envelope.getServerGuid().getBytes(StandardCharsets.UTF_8), // guid
+        envelope.toByteArray(), // message
+        UUIDUtil.fromByteString(envelope.getServerGuid()).toString().getBytes(StandardCharsets.UTF_8), // guid
         NEW_MESSAGE_EVENT_BYTES // eventPayload
     ));
 

service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesDynamoDb.java

@@ -27,8 +27,8 @@ import org.reactivestreams.Publisher;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
 import org.whispersystems.textsecuregcm.util.AttributeValues;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.publisher.Flux;
 import software.amazon.awssdk.core.SdkBytes;
 import software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient;
@@ -63,13 +63,11 @@ public class MessagesDynamoDb extends AbstractDynamoDbStore {
   private final String tableName;
   private final Duration timeToLive;
   private final ExecutorService messageDeletionExecutor;
-  private final ExperimentEnrollmentManager experimentEnrollmentManager;
 
   private static final Logger logger = LoggerFactory.getLogger(MessagesDynamoDb.class);
 
   public MessagesDynamoDb(DynamoDbClient dynamoDb, DynamoDbAsyncClient dynamoDbAsyncClient, String tableName,
-      Duration timeToLive, ExecutorService messageDeletionExecutor,
-      final ExperimentEnrollmentManager experimentEnrollmentManager) {
+      Duration timeToLive, ExecutorService messageDeletionExecutor) {
     super(dynamoDb);
 
     this.dbAsyncClient = dynamoDbAsyncClient;
@@ -77,7 +75,6 @@ public class MessagesDynamoDb extends AbstractDynamoDbStore {
     this.timeToLive = timeToLive;
 
     this.messageDeletionExecutor = messageDeletionExecutor;
-    this.experimentEnrollmentManager = experimentEnrollmentManager;
   }
 
   public void store(final List<MessageProtos.Envelope> messages, final UUID destinationAccountUuid,
@@ -94,14 +91,14 @@ public class MessagesDynamoDb extends AbstractDynamoDbStore {
     final AttributeValue partitionKey = convertPartitionKey(destinationAccountUuid, destinationDevice);
     List<WriteRequest> writeItems = new ArrayList<>();
     for (MessageProtos.Envelope message : messages) {
-      final UUID messageUuid = UUID.fromString(message.getServerGuid());
+      final UUID messageUuid = UUIDUtil.fromByteString(message.getServerGuid());
 
       final ImmutableMap.Builder<String, AttributeValue> item = ImmutableMap.<String, AttributeValue>builder()
           .put(KEY_PARTITION, partitionKey)
           .put(KEY_SORT, convertSortKey(message.getServerTimestamp(), messageUuid))
           .put(LOCAL_INDEX_MESSAGE_UUID_KEY_SORT, convertLocalIndexMessageUuidSortKey(messageUuid))
           .put(KEY_TTL, AttributeValues.fromLong(getTtlForMessage(message)))
-          .put(KEY_ENVELOPE_BYTES, AttributeValue.builder().b(SdkBytes.fromByteArray(EnvelopeUtil.compress(message).toByteArray())).build());
+          .put(KEY_ENVELOPE_BYTES, AttributeValue.builder().b(SdkBytes.fromByteArray(message.toByteArray())).build());
 
       writeItems.add(WriteRequest.builder().putRequest(PutRequest.builder()
           .item(item.build())
@@ -147,7 +144,7 @@ public class MessagesDynamoDb extends AbstractDynamoDbStore {
     return dbAsyncClient.queryPaginator(queryRequest).items()
         .map(message -> {
           try {
-            return convertItemToEnvelope(message, experimentEnrollmentManager);
+            return convertItemToEnvelope(message);
           } catch (final InvalidProtocolBufferException e) {
             logger.error("Failed to parse envelope", e);
             return null;
@@ -167,7 +164,7 @@ public class MessagesDynamoDb extends AbstractDynamoDbStore {
         .thenApplyAsync(deleteItemResponse -> {
           if (deleteItemResponse.attributes() != null && deleteItemResponse.attributes().containsKey(KEY_PARTITION)) {
             try {
-              return Optional.of(convertItemToEnvelope(deleteItemResponse.attributes(), experimentEnrollmentManager));
+              return Optional.of(convertItemToEnvelope(deleteItemResponse.attributes()));
             } catch (final InvalidProtocolBufferException e) {
               logger.error("Failed to parse envelope", e);
             }
@@ -178,11 +175,10 @@ public class MessagesDynamoDb extends AbstractDynamoDbStore {
   }
 
   @VisibleForTesting
-  static MessageProtos.Envelope convertItemToEnvelope(final Map<String, AttributeValue> item,
-      final ExperimentEnrollmentManager experimentEnrollmentManager) throws InvalidProtocolBufferException {
+  static MessageProtos.Envelope convertItemToEnvelope(final Map<String, AttributeValue> item)
+      throws InvalidProtocolBufferException {
 
-    return EnvelopeUtil.expand(MessageProtos.Envelope.parseFrom(item.get(KEY_ENVELOPE_BYTES).b().asByteArray()),
-        experimentEnrollmentManager);
+    return MessageProtos.Envelope.parseFrom(item.get(KEY_ENVELOPE_BYTES).b().asByteArray());
   }
 
   private long getTtlForMessage(MessageProtos.Envelope message) {

service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesManager.java

@@ -34,6 +34,7 @@ import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
 import org.whispersystems.textsecuregcm.metrics.MetricsUtil;
 import org.whispersystems.textsecuregcm.push.RedisMessageAvailabilityManager;
 import org.whispersystems.textsecuregcm.util.Pair;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.observability.micrometer.Micrometer;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -102,10 +103,14 @@ public class MessagesManager {
 
               return messagesCache.insert(messageGuid, accountIdentifier, deviceId, message)
                   .thenAccept(present -> {
-                    if (message.hasSourceServiceId() && !accountIdentifier.toString()
-                        .equals(message.getSourceServiceId())) {
-                      // Note that this is an asynchronous, best-effort, fire-and-forget operation
-                      reportMessageManager.store(message.getSourceServiceId(), messageGuid);
+                    if (message.hasSourceServiceId()) {
+                      final ServiceIdentifier sourceServiceIdentifier =
+                          ServiceIdentifier.fromByteString(message.getSourceServiceId());
+
+                      if (!accountIdentifier.equals(sourceServiceIdentifier.uuid())) {
+                        // Note that this is an asynchronous, best-effort, fire-and-forget operation
+                        reportMessageManager.store(sourceServiceIdentifier.toServiceIdentifierString(), messageGuid);
+                      }
                     }
 
                     devicePresenceById.put(deviceId, present);
@@ -170,8 +175,8 @@ public class MessagesManager {
 
                     return insertAsync(resolvedRecipients.get(recipient).getIdentifier(IdentityType.ACI),
                         IntStream.range(0, devices.length).mapToObj(i -> devices[i])
-                            .collect(Collectors.toMap(deviceId -> deviceId, deviceId -> prototypeMessage.toBuilder()
-                                .setDestinationServiceId(serviceIdentifier.toServiceIdentifierString())
+                            .collect(Collectors.toMap(deviceId -> deviceId, _ -> prototypeMessage.toBuilder()
+                                .setDestinationServiceId(serviceIdentifier.toCompactByteString())
                                 .build())))
                         .thenAccept(clientPresenceByDeviceId ->
                             clientPresenceByAccountAndDevice.put(resolvedRecipients.get(recipient),
@@ -275,7 +280,7 @@ public class MessagesManager {
 
     messagesDynamoDb.store(messages, destinationUuid, destinationDevice);
 
-    final List<UUID> messageGuids = messages.stream().map(message -> UUID.fromString(message.getServerGuid()))
+    final List<UUID> messageGuids = messages.stream().map(message -> UUIDUtil.fromByteString(message.getServerGuid()))
         .collect(Collectors.toList());
     int messagesRemovedFromCache = 0;
     try {

service/src/main/java/org/whispersystems/textsecuregcm/storage/RedisDynamoDbMessageStream.java

@@ -11,6 +11,7 @@ import java.util.concurrent.Flow;
 import com.google.common.annotations.VisibleForTesting;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.push.RedisMessageAvailabilityManager;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import org.whispersystems.textsecuregcm.util.Util;
 
 /// A [MessageStream] implementation that produces message from a joint DynamoDB/Redis message store.
@@ -58,7 +59,7 @@ public class RedisDynamoDbMessageStream implements MessageStream {
 
   @Override
   public CompletableFuture<Void> acknowledgeMessage(final MessageProtos.Envelope message) {
-    final UUID guid = UUID.fromString(message.getServerGuid());
+    final UUID guid = UUIDUtil.fromByteString(message.getServerGuid());
 
     return messagesCache.remove(accountIdentifier, device.getId(), guid)
         .thenCompose(removed -> removed.map(_ -> CompletableFuture.<Void>completedFuture(null))

service/src/main/java/org/whispersystems/textsecuregcm/storage/RemovedMessage.java

@@ -10,6 +10,7 @@ import java.util.Optional;
 import java.util.UUID;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 public record RemovedMessage(Optional<ServiceIdentifier> sourceServiceId, ServiceIdentifier destinationServiceId,
                              @VisibleForTesting UUID serverGuid, long serverTimestamp, long clientTimestamp,
@@ -18,10 +19,10 @@ public record RemovedMessage(Optional<ServiceIdentifier> sourceServiceId, Servic
   public static RemovedMessage fromEnvelope(MessageProtos.Envelope envelope) {
     return new RemovedMessage(
         envelope.hasSourceServiceId()
-            ? Optional.of(ServiceIdentifier.valueOf(envelope.getSourceServiceId()))
+            ? Optional.of(ServiceIdentifier.fromByteString(envelope.getSourceServiceId()))
             : Optional.empty(),
-        ServiceIdentifier.valueOf(envelope.getDestinationServiceId()),
-        UUID.fromString(envelope.getServerGuid()),
+        ServiceIdentifier.fromByteString(envelope.getDestinationServiceId()),
+        UUIDUtil.fromByteString(envelope.getServerGuid()),
         envelope.getServerTimestamp(),
         envelope.getClientTimestamp(),
         envelope.getType()

service/src/main/java/org/whispersystems/textsecuregcm/storage/foundationdb/FoundationDbMessageStream.java

@@ -160,7 +160,7 @@ public class FoundationDbMessageStream implements MessageStream {
   @Override
   public CompletableFuture<Void> acknowledgeMessage(final MessageProtos.Envelope message) {
     acknowledgedMessageBuffer.acknowledgeMessage(
-        messageGuidCodec.decodeMessageGuid(UUIDUtil.fromByteString(message.getServerGuidBinary())));
+        messageGuidCodec.decodeMessageGuid(UUIDUtil.fromByteString(message.getServerGuid())));
 
     return CompletableFuture.completedFuture(null);
   }

service/src/main/java/org/whispersystems/textsecuregcm/storage/foundationdb/FoundationDbMessageStreamEntry.java

@@ -16,7 +16,7 @@ sealed interface FoundationDbMessageStreamEntry permits FoundationDbMessageStrea
     return switch (this) {
       case Message(final Versionstamp versionstamp, final MessageProtos.Envelope partialEnvelope): {
         yield new MessageStreamEntry.Envelope(partialEnvelope.toBuilder()
-            .setServerGuidBinary(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp)))
+            .setServerGuid(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp)))
             .build());
       }
       case QueueEmpty():

service/src/main/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnection.java

@@ -15,9 +15,9 @@ import io.micrometer.core.instrument.Tags;
 import io.micrometer.core.instrument.Timer;
 import java.time.Duration;
 import java.util.Collections;
+import java.util.HexFormat;
 import java.util.List;
 import java.util.Optional;
-import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -44,11 +44,11 @@ import org.whispersystems.textsecuregcm.storage.Account;
 import org.whispersystems.textsecuregcm.storage.ClientReleaseManager;
 import org.whispersystems.textsecuregcm.storage.ConflictingMessageConsumerException;
 import org.whispersystems.textsecuregcm.storage.Device;
-import org.whispersystems.textsecuregcm.storage.EnvelopeUtil;
 import org.whispersystems.textsecuregcm.storage.MessageStream;
 import org.whispersystems.textsecuregcm.storage.MessageStreamEntry;
 import org.whispersystems.textsecuregcm.storage.MessagesManager;
 import org.whispersystems.textsecuregcm.util.HeaderUtils;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import org.whispersystems.websocket.WebSocketClient;
 import org.whispersystems.websocket.WebSocketResourceProvider;
 import org.whispersystems.websocket.messages.WebSocketResponseMessage;
@@ -93,8 +93,6 @@ public class WebSocketConnection implements DisconnectionRequestListener {
 
   private static final Duration CLOSE_WITH_PENDING_MESSAGES_NOTIFICATION_DELAY = Duration.ofMinutes(1);
 
-  private static final String RECOMPRESS_ENVELOPE_EXPERIMENT_NAME = "recompressEnvelopes";
-
   private static final Logger logger = LoggerFactory.getLogger(WebSocketConnection.class);
 
   private final ReceiptSender receiptSender;
@@ -173,7 +171,7 @@ public class WebSocketConnection implements DisconnectionRequestListener {
             if (hasSentFirstMessage.compareAndSet(false, true)) {
               messageDeliveryLoopMonitor.recordDeliveryAttempt(authenticatedAccount.getIdentifier(IdentityType.ACI),
                   authenticatedDevice.getId(),
-                  UUID.fromString(message.getServerGuid()),
+                  UUIDUtil.fromByteString(message.getServerGuid()),
                   client.getUserAgent(),
                   "websocket");
             }
@@ -241,11 +239,7 @@ public class WebSocketConnection implements DisconnectionRequestListener {
       return messageStream.acknowledgeMessage(message);
     }
 
-    final boolean recompressEnvelope =
-        experimentEnrollmentManager.isEnrolled(authenticatedAccount.getIdentifier(IdentityType.ACI), RECOMPRESS_ENVELOPE_EXPERIMENT_NAME);
-
-    final Optional<byte[]> body =
-        Optional.of(serializeMessage(recompressEnvelope ? EnvelopeUtil.compress(message) : message));
+    final Optional<byte[]> body = Optional.of(serializeMessage(message));
 
     sendMessageCounter.increment();
     sentMessageCounter.increment();
@@ -308,11 +302,11 @@ public class WebSocketConnection implements DisconnectionRequestListener {
     }
 
     try {
-      receiptSender.sendReceipt(ServiceIdentifier.valueOf(message.getDestinationServiceId()),
-          authenticatedDevice.getId(), AciServiceIdentifier.valueOf(message.getSourceServiceId()),
+      receiptSender.sendReceipt(ServiceIdentifier.fromByteString(message.getDestinationServiceId()),
+          authenticatedDevice.getId(), AciServiceIdentifier.fromByteString(message.getSourceServiceId()),
           message.getClientTimestamp());
     } catch (final IllegalArgumentException e) {
-      logger.error("Could not parse UUID: {}", message.getSourceServiceId());
+      logger.error("Could not parse UUID: {}", HexFormat.of().formatHex(message.getSourceServiceId().toByteArray()));
     } catch (final Exception e) {
       logger.warn("Failed to send receipt", e);
     }

service/src/main/java/org/whispersystems/textsecuregcm/workers/CommandDependencies.java

@@ -245,7 +245,7 @@ public record CommandDependencies(
     MessagesDynamoDb messagesDynamoDb = new MessagesDynamoDb(dynamoDbClient, dynamoDbAsyncClient,
         configuration.getDynamoDbTables().getMessages().getTableName(),
         configuration.getDynamoDbTables().getMessages().getExpiration(),
-        messageDeletionExecutor, experimentEnrollmentManager);
+        messageDeletionExecutor);
     FaultTolerantRedisClusterClient messagesCluster = configuration.getMessageCacheConfiguration()
         .getRedisClusterConfiguration().build("messages", redisClientResourcesBuilder);
     FaultTolerantRedisClusterClient rateLimitersCluster = configuration.getRateLimitersCluster().build("rate_limiters",
@@ -267,7 +267,7 @@ public record CommandDependencies(
     DisconnectionRequestManager disconnectionRequestManager = new DisconnectionRequestManager(pubsubClient,
         disconnectionRequestListenerExecutor, retryExecutor);
     MessagesCache messagesCache = new MessagesCache(messagesCluster,
-        messageDeliveryScheduler, messageDeletionExecutor, retryExecutor, Clock.systemUTC(), experimentEnrollmentManager);
+        messageDeliveryScheduler, messageDeletionExecutor, retryExecutor, Clock.systemUTC());
     ProfilesManager profilesManager = new ProfilesManager(profilesV1, profiles, cacheCluster, retryExecutor, asyncCdnS3Client,
         configuration.getCdnConfiguration().bucket());
     ReportMessageDynamoDb reportMessageDynamoDb = new ReportMessageDynamoDb(dynamoDbClient, dynamoDbAsyncClient,

service/src/main/proto/TextSecure.proto

@@ -21,25 +21,26 @@ message Envelope {
     PLAINTEXT_CONTENT = 8;  // for decryption error receipts
   }
 
+  reserved 9; // Formerly string server_guid;
+  reserved 11; // Formerly string source_service_id
+  reserved 13; // Formerly string destination_service_id
+  reserved 15; // Formerly string updated_pni;
+
   optional Type type = 1;
-  optional string source_service_id = 11;
   optional uint32 source_device = 7;
   optional uint64 client_timestamp = 5;
   optional bytes content = 8; // Contains an encrypted Content
-  optional string server_guid = 9;
   optional uint64 server_timestamp = 10;
   optional bool ephemeral = 12; // indicates that the message should not be persisted if the recipient is offline
-  optional string destination_service_id = 13;
   optional bool urgent = 14 [default=true];
-  optional string updated_pni = 15;
   optional bool story = 16; // indicates that the content is a story.
   optional bytes report_spam_token = 17; // token sent when reporting spam
   optional bytes shared_mrm_key = 18; // indicates content should be fetched from multi-recipient message datastore
-  optional bytes source_service_id_binary = 19; // service ID binary (i.e. 16 byte UUID for ACI, 1 byte prefix + 16 byte UUID for PNI)
-  optional bytes destination_service_id_binary = 20; // service ID binary (i.e. 16 byte UUID for ACI, 1 byte prefix + 16 byte UUID for PNI)
-  optional bytes server_guid_binary = 21; // 16-byte UUID
-  optional bytes updated_pni_binary = 22; // 16-byte UUID
-  // next: 22
+  optional bytes source_service_id = 19; // service ID binary (i.e. 16 byte UUID for ACI, 1 byte prefix + 16 byte UUID for PNI)
+  optional bytes destination_service_id = 20; // service ID binary (i.e. 16 byte UUID for ACI, 1 byte prefix + 16 byte UUID for PNI)
+  optional bytes server_guid = 21; // 16-byte UUID
+  optional bytes updated_pni = 22; // 16-byte UUID
+  // next: 23
 }
 
 message ProvisioningAddress {

service/src/test/java/org/whispersystems/textsecuregcm/grpc/AccountsAnonymousGrpcServiceTest.java

@@ -90,11 +90,11 @@ class AccountsAnonymousGrpcServiceTest extends
         .thenReturn(Optional.of(mock(Account.class)));
 
     assertTrue(unauthenticatedServiceStub().checkAccountExistence(CheckAccountExistenceRequest.newBuilder()
-        .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+        .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
         .build()).getAccountExists());
 
     assertFalse(unauthenticatedServiceStub().checkAccountExistence(CheckAccountExistenceRequest.newBuilder()
-        .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID())))
+        .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID())))
         .build()).getAccountExists());
   }
 
@@ -131,7 +131,7 @@ class AccountsAnonymousGrpcServiceTest extends
     //noinspection ResultOfMethodCallIgnored
     GrpcTestUtils.assertRateLimitExceeded(retryAfter,
         () -> unauthenticatedServiceStub().checkAccountExistence(CheckAccountExistenceRequest.newBuilder()
-            .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID())))
+            .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID())))
             .build()),
         accountsManager);
   }
@@ -148,7 +148,7 @@ class AccountsAnonymousGrpcServiceTest extends
     when(accountsManager.getByUsernameHash(usernameHash))
         .thenReturn(CompletableFuture.completedFuture(Optional.of(account)));
 
-    assertEquals(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(accountIdentifier)),
+    assertEquals(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(accountIdentifier)),
         unauthenticatedServiceStub().lookupUsernameHash(LookupUsernameHashRequest.newBuilder()
                 .setUsernameHash(ByteString.copyFrom(usernameHash))
                 .build())

service/src/test/java/org/whispersystems/textsecuregcm/grpc/AccountsGrpcServiceTest.java

@@ -132,8 +132,8 @@ class AccountsGrpcServiceTest extends SimpleBaseGrpcTest<AccountsGrpcService, Ac
 
     final GetAccountIdentityResponse expectedResponse = GetAccountIdentityResponse.newBuilder()
         .setAccountIdentifiers(AccountIdentifiers.newBuilder()
-            .addServiceIdentifiers(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(AUTHENTICATED_ACI)))
-            .addServiceIdentifiers(ServiceIdentifierUtil.toGrpcServiceIdentifier(new PniServiceIdentifier(phoneNumberIdentifier)))
+            .addServiceIdentifiers(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(AUTHENTICATED_ACI)))
+            .addServiceIdentifiers(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new PniServiceIdentifier(phoneNumberIdentifier)))
             .setE164(e164)
             .setUsernameHash(ByteString.copyFrom(usernameHash))
             .build())

service/src/test/java/org/whispersystems/textsecuregcm/grpc/KeysAnonymousGrpcServiceTest.java

@@ -37,7 +37,6 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.params.ParameterizedTest;
 import org.junitpioneer.jupiter.cartesian.CartesianTest;
 import org.mockito.Mock;
 import org.signal.chat.common.EcPreKey;
@@ -123,7 +122,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
     final GetPreKeysAnonymousResponse response = unauthenticatedServiceStub().getPreKeys(GetPreKeysAnonymousRequest.newBuilder()
         .setUnidentifiedAccessKey(ByteString.copyFrom(unidentifiedAccessKey))
         .setRequest(GetPreKeysRequest.newBuilder()
-            .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
+            .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
             .setDeviceId(Device.PRIMARY_ID))
         .build());
 
@@ -176,7 +175,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
     final GetPreKeysAnonymousResponse response = unauthenticatedServiceStub().getPreKeys(GetPreKeysAnonymousRequest.newBuilder()
         .setGroupSendToken(ByteString.copyFrom(token))
         .setRequest(GetPreKeysRequest.newBuilder()
-            .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
+            .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
             .setDeviceId(Device.PRIMARY_ID))
         .build());
 
@@ -223,7 +222,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
         .thenReturn(CompletableFuture.completedFuture(Optional.of(devicePreKeys)));
     final GetPreKeysAnonymousRequest.Builder request = GetPreKeysAnonymousRequest.newBuilder()
         .setRequest(GetPreKeysRequest.newBuilder()
-            .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
+            .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
             .setDeviceId(Device.PRIMARY_ID));
 
     if (includeUak) {
@@ -251,7 +250,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
   void getPreKeysNoAuth() {
     assertGetKeysFailure(Status.INVALID_ARGUMENT, GetPreKeysAnonymousRequest.newBuilder()
         .setRequest(GetPreKeysRequest.newBuilder()
-            .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID())))
+            .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID())))
             .setDeviceId(Device.PRIMARY_ID))
         .build());
 
@@ -275,7 +274,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
         GetPreKeysAnonymousRequest.newBuilder()
             .setUnidentifiedAccessKey(UUIDUtil.toByteString(UUID.randomUUID()))
             .setRequest(GetPreKeysRequest.newBuilder()
-                .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
+                .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
                 .setDeviceId(Device.PRIMARY_ID))
             .build());
 
@@ -298,7 +297,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
         unauthenticatedServiceStub().getPreKeys(GetPreKeysAnonymousRequest.newBuilder()
             .setGroupSendToken(ByteString.copyFrom(token))
             .setRequest(GetPreKeysRequest.newBuilder()
-                .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
+                .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(identifier))
                 .setDeviceId(Device.PRIMARY_ID))
             .build());
     assertTrue(preKeysResponse.hasFailedUnidentifiedAuthorization());
@@ -322,7 +321,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
         GetPreKeysAnonymousRequest.newBuilder()
             .setGroupSendToken(ByteString.copyFrom(token))
             .setRequest(GetPreKeysRequest.newBuilder()
-                .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(targetIdentifier))
+                .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(targetIdentifier))
                 .setDeviceId(Device.PRIMARY_ID))
             .build());
     assertTrue(response.hasFailedUnidentifiedAuthorization());
@@ -340,7 +339,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
         unauthenticatedServiceStub().getPreKeys(GetPreKeysAnonymousRequest.newBuilder()
             .setUnidentifiedAccessKey(UUIDUtil.toByteString(UUID.randomUUID()))
             .setRequest(GetPreKeysRequest.newBuilder()
-                .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(nonexistentAci)))
+                .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(nonexistentAci)))
             .build());
     assertTrue(preKeysResponse.hasFailedUnidentifiedAuthorization());
     verifyNoInteractions(keysManager);
@@ -363,7 +362,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
         unauthenticatedServiceStub().getPreKeys(GetPreKeysAnonymousRequest.newBuilder()
             .setGroupSendToken(ByteString.copyFrom(token))
             .setRequest(GetPreKeysRequest.newBuilder()
-                .setTargetIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(nonexistentAci)))
+                .setTargetIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(nonexistentAci)))
         .build());
     assertTrue(preKeysResponse.hasTargetNotFound());
     verifyNoInteractions(keysManager);
@@ -444,7 +443,7 @@ class KeysAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<KeysAnonymousGrpcS
           public void onNext(final CheckIdentityKeyResponse checkIdentityKeyResponse) {
             try {
               responses.put(
-                  ServiceIdentifierUtil.fromGrpcServiceIdentifier(checkIdentityKeyResponse.getTargetIdentifier()).uuid(),
+                  GrpcServiceIdentifierUtil.fromGrpcServiceIdentifier(checkIdentityKeyResponse.getTargetIdentifier()).uuid(),
                   new IdentityKey(checkIdentityKeyResponse.getIdentityKey().toByteArray()));
             } catch (final InvalidKeyException e) {
               throw new RuntimeException(e);

service/src/test/java/org/whispersystems/textsecuregcm/grpc/MessagesAnonymousGrpcServiceTest.java

@@ -197,7 +197,7 @@ class MessagesAnonymousGrpcServiceTest extends
 
       final MessageProtos.Envelope.Builder expectedEnvelopeBuilder = MessageProtos.Envelope.newBuilder()
           .setType(MessageProtos.Envelope.Type.UNIDENTIFIED_SENDER)
-          .setDestinationServiceId(serviceIdentifier.toServiceIdentifierString())
+          .setDestinationServiceId(serviceIdentifier.toCompactByteString())
           .setClientTimestamp(CLOCK.millis())
           .setServerTimestamp(CLOCK.millis())
           .setEphemeral(ephemeral)
@@ -318,7 +318,7 @@ class MessagesAnonymousGrpcServiceTest extends
 
       final SendMessageResponse expectedResponse = SendMessageResponse.newBuilder()
           .setMismatchedDevices(MismatchedDevices.newBuilder()
-              .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+              .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
               .addMissingDevices(missingDeviceId)
               .addStaleDevices(staleDeviceId)
               .addExtraDevices(extraDeviceId)
@@ -615,7 +615,7 @@ class MessagesAnonymousGrpcServiceTest extends
       messages.forEach(messageBundleBuilder::putMessages);
 
       final SendSealedSenderMessageRequest.Builder requestBuilder = SendSealedSenderMessageRequest.newBuilder()
-          .setDestination(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+          .setDestination(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
           .setMessages(messageBundleBuilder)
           .setEphemeral(ephemeral)
           .setUrgent(urgent);
@@ -687,7 +687,7 @@ class MessagesAnonymousGrpcServiceTest extends
 
       final SendMultiRecipientMessageResponse expectedResponse = SendMultiRecipientMessageResponse.newBuilder()
           .setSuccess(MultiRecipientSuccess.newBuilder()
-              .addUnresolvedRecipients(ServiceIdentifierUtil.toGrpcServiceIdentifier(unresolvedServiceIdentifier))
+              .addUnresolvedRecipients(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(unresolvedServiceIdentifier))
               .build())
           .build();
 
@@ -740,7 +740,7 @@ class MessagesAnonymousGrpcServiceTest extends
       final SendMultiRecipientMessageResponse expectedResponse = SendMultiRecipientMessageResponse.newBuilder()
           .setMismatchedDevices(MultiRecipientMismatchedDevices.newBuilder()
               .addMismatchedDevices(MismatchedDevices.newBuilder()
-                  .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+                  .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
                   .addMissingDevices(missingDeviceId)
                   .addExtraDevices(extraDeviceId)
                   .addStaleDevices(staleDeviceId)
@@ -1061,7 +1061,7 @@ class MessagesAnonymousGrpcServiceTest extends
 
       final MessageProtos.Envelope.Builder expectedEnvelopeBuilder = MessageProtos.Envelope.newBuilder()
           .setType(MessageProtos.Envelope.Type.UNIDENTIFIED_SENDER)
-          .setDestinationServiceId(serviceIdentifier.toServiceIdentifierString())
+          .setDestinationServiceId(serviceIdentifier.toCompactByteString())
           .setClientTimestamp(CLOCK.millis())
           .setServerTimestamp(CLOCK.millis())
           .setEphemeral(false)
@@ -1115,7 +1115,7 @@ class MessagesAnonymousGrpcServiceTest extends
 
       final SendMessageResponse expectedResponse = SendMessageResponse.newBuilder()
           .setMismatchedDevices(MismatchedDevices.newBuilder()
-              .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+              .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
               .addMissingDevices(missingDeviceId)
               .addStaleDevices(staleDeviceId)
               .addExtraDevices(extraDeviceId)
@@ -1323,7 +1323,7 @@ class MessagesAnonymousGrpcServiceTest extends
       messages.forEach(messageBundleBuilder::putMessages);
 
       return SendStoryMessageRequest.newBuilder()
-          .setDestination(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+          .setDestination(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
           .setMessages(messageBundleBuilder)
           .setUrgent(urgent)
           .build();
@@ -1424,7 +1424,7 @@ class MessagesAnonymousGrpcServiceTest extends
       final SendMultiRecipientMessageResponse expectedResponse = SendMultiRecipientMessageResponse.newBuilder()
           .setMismatchedDevices(MultiRecipientMismatchedDevices.newBuilder()
               .addMismatchedDevices(MismatchedDevices.newBuilder()
-                  .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+                  .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
                   .addMissingDevices(missingDeviceId)
                   .addExtraDevices(extraDeviceId)
                   .addStaleDevices(staleDeviceId)

service/src/test/java/org/whispersystems/textsecuregcm/grpc/MessagesGrpcServiceTest.java

@@ -201,9 +201,9 @@ class MessagesGrpcServiceTest extends SimpleBaseGrpcTest<MessagesGrpcService, Me
 
       final MessageProtos.Envelope.Builder expectedEnvelopeBuilder = MessageProtos.Envelope.newBuilder()
           .setType(expectedEnvelopeType)
-          .setSourceServiceId(new AciServiceIdentifier(AUTHENTICATED_ACI).toServiceIdentifierString())
+          .setSourceServiceId(new AciServiceIdentifier(AUTHENTICATED_ACI).toCompactByteString())
           .setSourceDevice(AUTHENTICATED_DEVICE_ID)
-          .setDestinationServiceId(serviceIdentifier.toServiceIdentifierString())
+          .setDestinationServiceId(serviceIdentifier.toCompactByteString())
           .setClientTimestamp(CLOCK.millis())
           .setServerTimestamp(CLOCK.millis())
           .setEphemeral(ephemeral)
@@ -286,7 +286,7 @@ class MessagesGrpcServiceTest extends SimpleBaseGrpcTest<MessagesGrpcService, Me
 
       final SendMessageAuthenticatedSenderResponse expectedResponse = SendMessageAuthenticatedSenderResponse.newBuilder()
           .setMismatchedDevices(MismatchedDevices.newBuilder()
-              .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+              .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
               .addMissingDevices(missingDeviceId)
               .addStaleDevices(staleDeviceId)
               .addExtraDevices(extraDeviceId)
@@ -504,7 +504,7 @@ class MessagesGrpcServiceTest extends SimpleBaseGrpcTest<MessagesGrpcService, Me
       messages.forEach(messageBundleBuilder::putMessages);
 
       final SendAuthenticatedSenderMessageRequest.Builder requestBuilder = SendAuthenticatedSenderMessageRequest.newBuilder()
-          .setDestination(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+          .setDestination(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
           .setMessages(messageBundleBuilder)
           .setEphemeral(ephemeral)
           .setUrgent(urgent);
@@ -560,9 +560,9 @@ class MessagesGrpcServiceTest extends SimpleBaseGrpcTest<MessagesGrpcService, Me
       final Map<Byte, MessageProtos.Envelope> expectedEnvelopes = new HashMap<>(Map.of(
           LINKED_DEVICE_ID, MessageProtos.Envelope.newBuilder()
               .setType(expectedEnvelopeType)
-              .setSourceServiceId(serviceIdentifier.toServiceIdentifierString())
+              .setSourceServiceId(serviceIdentifier.toCompactByteString())
               .setSourceDevice(AUTHENTICATED_DEVICE_ID)
-              .setDestinationServiceId(serviceIdentifier.toServiceIdentifierString())
+              .setDestinationServiceId(serviceIdentifier.toCompactByteString())
               .setClientTimestamp(CLOCK.millis())
               .setServerTimestamp(CLOCK.millis())
               .setEphemeral(false)
@@ -572,9 +572,9 @@ class MessagesGrpcServiceTest extends SimpleBaseGrpcTest<MessagesGrpcService, Me
 
           SECOND_LINKED_DEVICE_ID, MessageProtos.Envelope.newBuilder()
               .setType(expectedEnvelopeType)
-              .setSourceServiceId(serviceIdentifier.toServiceIdentifierString())
+              .setSourceServiceId(serviceIdentifier.toCompactByteString())
               .setSourceDevice(AUTHENTICATED_DEVICE_ID)
-              .setDestinationServiceId(serviceIdentifier.toServiceIdentifierString())
+              .setDestinationServiceId(serviceIdentifier.toCompactByteString())
               .setClientTimestamp(CLOCK.millis())
               .setServerTimestamp(CLOCK.millis())
               .setEphemeral(false)
@@ -625,7 +625,7 @@ class MessagesGrpcServiceTest extends SimpleBaseGrpcTest<MessagesGrpcService, Me
 
       final SendMessageAuthenticatedSenderResponse expectedResponse = SendMessageAuthenticatedSenderResponse.newBuilder()
           .setMismatchedDevices(MismatchedDevices.newBuilder()
-              .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(AUTHENTICATED_ACI)))
+              .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(AUTHENTICATED_ACI)))
               .addMissingDevices(missingDeviceId)
               .addStaleDevices(staleDeviceId)
               .addExtraDevices(extraDeviceId)

service/src/test/java/org/whispersystems/textsecuregcm/grpc/ProfileAnonymousGrpcServiceTest.java

@@ -221,7 +221,7 @@ public class ProfileAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<ProfileA
         .setGroupSendToken(ByteString.copyFrom(token))
         .setRequest(GetUnversionedProfileRequest.newBuilder()
             .setServiceIdentifier(
-                ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
+                GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier))
             .build())
         .build();
 
@@ -243,7 +243,7 @@ public class ProfileAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<ProfileA
   void getUnversionedProfileNoAuth() {
     final GetUnversionedProfileAnonymousRequest request = GetUnversionedProfileAnonymousRequest.newBuilder()
         .setRequest(GetUnversionedProfileRequest.newBuilder()
-            .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID()))))
+            .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(new AciServiceIdentifier(UUID.randomUUID()))))
         .build();
 
     assertStatusException(Status.INVALID_ARGUMENT, () -> unauthenticatedServiceStub().getUnversionedProfile(request));
@@ -303,7 +303,7 @@ public class ProfileAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<ProfileA
         .setGroupSendToken(ByteString.copyFrom(token))
         .setRequest(GetUnversionedProfileRequest.newBuilder()
             .setServiceIdentifier(
-                ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier)))
+                GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier)))
         .build();
 
     final GetUnversionedProfileAnonymousResponse response = unauthenticatedServiceStub().getUnversionedProfile(
@@ -327,7 +327,7 @@ public class ProfileAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<ProfileA
         .setGroupSendToken(ByteString.copyFrom(token))
         .setRequest(GetUnversionedProfileRequest.newBuilder()
             .setServiceIdentifier(
-                ServiceIdentifierUtil.toGrpcServiceIdentifier(targetServiceIdentifier)))
+                GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(targetServiceIdentifier)))
         .build();
 
     final GetUnversionedProfileAnonymousResponse response = unauthenticatedServiceStub().getUnversionedProfile(request);
@@ -347,7 +347,7 @@ public class ProfileAnonymousGrpcServiceTest extends SimpleBaseGrpcTest<ProfileA
     final GetUnversionedProfileAnonymousRequest request = GetUnversionedProfileAnonymousRequest.newBuilder()
         .setGroupSendToken(ByteString.copyFrom(token))
         .setRequest(GetUnversionedProfileRequest.newBuilder()
-            .setServiceIdentifier(ServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier)))
+            .setServiceIdentifier(GrpcServiceIdentifierUtil.toGrpcServiceIdentifier(serviceIdentifier)))
         .build();
 
     final GetUnversionedProfileAnonymousResponse response = unauthenticatedServiceStub().getUnversionedProfile(

service/src/test/java/org/whispersystems/textsecuregcm/metrics/MessageMetricsTest.java

@@ -76,7 +76,7 @@ class MessageMetricsTest {
     final MessageProtos.Envelope.Builder builder = MessageProtos.Envelope.newBuilder();
 
     if (destinationIdentifier != null) {
-      builder.setDestinationServiceId(destinationIdentifier.toServiceIdentifierString());
+      builder.setDestinationServiceId(destinationIdentifier.toCompactByteString());
     }
 
     return builder.build();

service/src/test/java/org/whispersystems/textsecuregcm/push/MessageSenderTest.java

@@ -555,7 +555,7 @@ class MessageSenderTest {
         .setContent(ByteString.copyFrom(TestRandomUtil.nextBytes(contentLength)));
 
     if (sourceIdentifier != null) {
-      envelopeBuilder.setSourceServiceId(sourceIdentifier.toServiceIdentifierString());
+      envelopeBuilder.setSourceServiceId(sourceIdentifier.toCompactByteString());
     }
 
     return envelopeBuilder.build();
@@ -704,7 +704,7 @@ class MessageSenderTest {
     assertThrows(IllegalArgumentException.class, () -> messageSender.sendMessages(account,
         serviceIdentifier,
         Map.of(deviceId, MessageProtos.Envelope.newBuilder()
-            .setSourceServiceId(serviceIdentifier.toServiceIdentifierString())
+            .setSourceServiceId(serviceIdentifier.toCompactByteString())
             .setSourceDevice(deviceId)
             .build()),
         Map.of(deviceId, 17),

service/src/test/java/org/whispersystems/textsecuregcm/storage/ChangeNumberManagerTest.java

@@ -60,6 +60,7 @@ import org.whispersystems.textsecuregcm.push.MessageTooLargeException;
 import org.whispersystems.textsecuregcm.tests.util.KeysHelper;
 import org.whispersystems.textsecuregcm.util.Pair;
 import org.whispersystems.textsecuregcm.util.TestClock;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 public class ChangeNumberManagerTest {
   private MessageSender messageSender;
@@ -245,11 +246,11 @@ public class ChangeNumberManagerTest {
         .setType(MessageProtos.Envelope.Type.forNumber(incomingMessage.type()))
         .setClientTimestamp(CLOCK.millis())
         .setServerTimestamp(CLOCK.millis())
-        .setDestinationServiceId(new AciServiceIdentifier(aci).toServiceIdentifierString())
+        .setDestinationServiceId(new AciServiceIdentifier(aci).toCompactByteString())
         .setContent(ByteString.copyFrom(incomingMessage.content()))
-        .setSourceServiceId(new AciServiceIdentifier(aci).toServiceIdentifierString())
+        .setSourceServiceId(new AciServiceIdentifier(aci).toCompactByteString())
         .setSourceDevice(primaryDeviceId)
-        .setUpdatedPni(updatedPhoneNumberIdentifiersByAccount.get(account).toString())
+        .setUpdatedPni(UUIDUtil.toByteString(updatedPhoneNumberIdentifiersByAccount.get(account)))
         .setUrgent(true)
         .setEphemeral(false)
         .build();

service/src/test/java/org/whispersystems/textsecuregcm/storage/EnvelopeUtilTest.java

@@ -1,135 +0,0 @@
-/*
- * Copyright 2025 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.whispersystems.textsecuregcm.storage;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.eq;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-
-import com.google.protobuf.ByteString;
-import java.util.UUID;
-import java.util.concurrent.ThreadLocalRandom;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.ValueSource;
-import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
-import org.whispersystems.textsecuregcm.grpc.ServiceIdentifierUtil;
-import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
-import org.whispersystems.textsecuregcm.identity.IdentityType;
-import org.whispersystems.textsecuregcm.identity.PniServiceIdentifier;
-import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
-import org.whispersystems.textsecuregcm.util.TestRandomUtil;
-import org.whispersystems.textsecuregcm.util.UUIDUtil;
-
-class EnvelopeUtilTest {
-
-  @ParameterizedTest
-  @ValueSource(booleans = {true, false})
-  void compressExpand(final boolean includeBinaryServiceIdentifiers) {
-    final ExperimentEnrollmentManager experimentEnrollmentManager = mock(ExperimentEnrollmentManager.class);
-    when(experimentEnrollmentManager.isEnrolled(any(UUID.class), eq(EnvelopeUtil.INCLUDE_BINARY_SERVICE_ID_EXPERIMENT_NAME)))
-        .thenReturn(includeBinaryServiceIdentifiers);
-
-    {
-      final MessageProtos.Envelope compressibleFieldsNullMessage = generateRandomMessageBuilder().build();
-      final MessageProtos.Envelope compressed = EnvelopeUtil.compress(compressibleFieldsNullMessage);
-
-      assertFalse(compressed.hasSourceServiceId());
-      assertFalse(compressed.hasSourceServiceIdBinary());
-      assertFalse(compressed.hasDestinationServiceId());
-      assertFalse(compressed.hasDestinationServiceIdBinary());
-      assertFalse(compressed.hasServerGuid());
-      assertFalse(compressed.hasServerGuidBinary());
-      assertFalse(compressed.hasUpdatedPni());
-      assertFalse(compressed.hasUpdatedPniBinary());
-
-      final MessageProtos.Envelope expanded = EnvelopeUtil.expand(compressed, experimentEnrollmentManager);
-
-      assertFalse(expanded.hasSourceServiceId());
-      assertFalse(expanded.hasSourceServiceIdBinary());
-      assertFalse(expanded.hasDestinationServiceId());
-      assertFalse(expanded.hasDestinationServiceIdBinary());
-      assertFalse(expanded.hasServerGuid());
-      assertFalse(expanded.hasServerGuidBinary());
-      assertFalse(compressed.hasUpdatedPni());
-      assertFalse(compressed.hasUpdatedPniBinary());
-    }
-
-    {
-      final ServiceIdentifier sourceServiceId = generateRandomServiceIdentifier();
-      final ServiceIdentifier destinationServiceId = generateRandomServiceIdentifier();
-      final UUID serverGuid = UUID.randomUUID();
-      final UUID updatedPni = UUID.randomUUID();
-
-      final MessageProtos.Envelope compressibleFieldsExpandedMessage = generateRandomMessageBuilder()
-          .setSourceServiceId(sourceServiceId.toServiceIdentifierString())
-          .setDestinationServiceId(destinationServiceId.toServiceIdentifierString())
-          .setServerGuid(serverGuid.toString())
-          .setUpdatedPni(updatedPni.toString())
-          .build();
-
-      final MessageProtos.Envelope compressed = EnvelopeUtil.compress(compressibleFieldsExpandedMessage);
-
-      assertFalse(compressed.hasSourceServiceId());
-      assertEquals(ServiceIdentifierUtil.toCompactByteString(sourceServiceId), compressed.getSourceServiceIdBinary());
-      assertFalse(compressed.hasDestinationServiceId());
-      assertEquals(ServiceIdentifierUtil.toCompactByteString(destinationServiceId), compressed.getDestinationServiceIdBinary());
-      assertFalse(compressed.hasServerGuid());
-      assertEquals(UUIDUtil.toByteString(serverGuid), compressed.getServerGuidBinary());
-      assertFalse(compressed.hasUpdatedPni());
-      assertEquals(UUIDUtil.toByteString(updatedPni), compressed.getUpdatedPniBinary());
-
-      assertEquals(compressed, EnvelopeUtil.compress(compressed), "Double compression should make no changes");
-
-      final MessageProtos.Envelope expanded = EnvelopeUtil.expand(compressed, experimentEnrollmentManager);
-
-      assertEquals(sourceServiceId.toServiceIdentifierString(), expanded.getSourceServiceId());
-      assertEquals(destinationServiceId.toServiceIdentifierString(), expanded.getDestinationServiceId());
-      assertEquals(serverGuid.toString(), expanded.getServerGuid());
-      assertEquals(updatedPni.toString(), expanded.getUpdatedPni());
-      assertEquals(UUIDUtil.toByteString(updatedPni), expanded.getUpdatedPniBinary());
-
-      if (includeBinaryServiceIdentifiers) {
-        assertEquals(ServiceIdentifierUtil.toCompactByteString(sourceServiceId), expanded.getSourceServiceIdBinary());
-        assertEquals(ServiceIdentifierUtil.toCompactByteString(destinationServiceId), expanded.getDestinationServiceIdBinary());
-        assertEquals(UUIDUtil.toByteString(serverGuid), expanded.getServerGuidBinary());
-      } else {
-        assertFalse(expanded.hasSourceServiceIdBinary());
-        assertFalse(expanded.hasDestinationServiceIdBinary());
-        assertFalse(expanded.hasServerGuidBinary());
-      }
-
-      assertEquals(expanded, EnvelopeUtil.expand(expanded, experimentEnrollmentManager),
-          "Double expansion should make no changes");
-
-      // Expanded envelopes include both representations of the `updatedPni` field
-      assertTrue(expanded.hasUpdatedPni());
-      assertTrue(expanded.hasUpdatedPniBinary());
-      assertEquals(UUID.fromString(expanded.getUpdatedPni()), UUIDUtil.fromByteString(expanded.getUpdatedPniBinary()));
-    }
-  }
-
-  private static ServiceIdentifier generateRandomServiceIdentifier() {
-    final IdentityType identityType = ThreadLocalRandom.current().nextBoolean() ? IdentityType.ACI : IdentityType.PNI;
-
-    return switch (identityType) {
-      case ACI -> new AciServiceIdentifier(UUID.randomUUID());
-      case PNI -> new PniServiceIdentifier(UUID.randomUUID());
-    };
-  }
-
-  private MessageProtos.Envelope.Builder generateRandomMessageBuilder() {
-    return MessageProtos.Envelope.newBuilder()
-        .setClientTimestamp(ThreadLocalRandom.current().nextLong())
-        .setServerTimestamp(ThreadLocalRandom.current().nextLong())
-        .setContent(ByteString.copyFrom(TestRandomUtil.nextBytes(256)))
-        .setType(MessageProtos.Envelope.Type.CIPHERTEXT);
-  }
-}

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagePersisterIntegrationTest.java

@@ -36,12 +36,13 @@ import org.junit.jupiter.api.extension.RegisterExtension;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfiguration;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicMessagePersisterConfiguration;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
+import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.push.MessageAvailabilityListener;
 import org.whispersystems.textsecuregcm.push.RedisMessageAvailabilityManager;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
 import org.whispersystems.textsecuregcm.storage.DynamoDbExtensionSchema.Tables;
 import org.whispersystems.textsecuregcm.tests.util.DevicesHelper;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.scheduler.Scheduler;
 import reactor.core.scheduler.Schedulers;
 import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
@@ -64,7 +65,6 @@ class MessagePersisterIntegrationTest {
   private RedisMessageAvailabilityManager redisMessageAvailabilityManager;
   private MessagePersister messagePersister;
   private Account account;
-  private ExperimentEnrollmentManager experimentEnrollmentManager;
 
   private static final Duration PERSIST_DELAY = Duration.ofMinutes(10);
 
@@ -85,14 +85,13 @@ class MessagePersisterIntegrationTest {
     messageDeliveryScheduler = Schedulers.newBoundedElastic(10, 10_000, "messageDelivery");
     persistQueueScheduler = Schedulers.newBoundedElastic(10, 10_000, "persistQueue");
     messageDeletionExecutorService = Executors.newSingleThreadExecutor();
-    experimentEnrollmentManager = mock(ExperimentEnrollmentManager.class);
     final MessagesDynamoDb messagesDynamoDb = new MessagesDynamoDb(DYNAMO_DB_EXTENSION.getDynamoDbClient(),
         DYNAMO_DB_EXTENSION.getDynamoDbAsyncClient(), Tables.MESSAGES.tableName(), Duration.ofDays(14),
-        messageDeletionExecutorService, experimentEnrollmentManager);
+        messageDeletionExecutorService);
     final AccountsManager accountsManager = mock(AccountsManager.class);
 
     messagesCache = new MessagesCache(REDIS_CLUSTER_EXTENSION.getRedisCluster(),
-        messageDeliveryScheduler, messageDeletionExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC(), experimentEnrollmentManager);
+        messageDeliveryScheduler, messageDeletionExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC());
 
     final MessagesManager messagesManager = new MessagesManager(messagesDynamoDb,
         messagesCache,
@@ -199,7 +198,7 @@ class MessagePersisterIntegrationTest {
         dynamoDB.scan(ScanRequest.builder().tableName(Tables.MESSAGES.tableName()).build()).items().stream()
             .map(item -> {
               try {
-                return MessagesDynamoDb.convertItemToEnvelope(item, experimentEnrollmentManager);
+                return MessagesDynamoDb.convertItemToEnvelope(item);
               } catch (InvalidProtocolBufferException e) {
                 fail("Could not parse stored message", e);
                 return null;
@@ -246,7 +245,7 @@ class MessagePersisterIntegrationTest {
         dynamoDB.scan(ScanRequest.builder().tableName(Tables.MESSAGES.tableName()).build()).items().stream()
             .map(item -> {
               try {
-                return MessagesDynamoDb.convertItemToEnvelope(item, experimentEnrollmentManager);
+                return MessagesDynamoDb.convertItemToEnvelope(item);
               } catch (InvalidProtocolBufferException e) {
                 fail("Could not parse stored message", e);
                 return null;
@@ -264,8 +263,8 @@ class MessagePersisterIntegrationTest {
         .setServerTimestamp(serverTimestamp)
         .setContent(ByteString.copyFromUtf8(RandomStringUtils.secure().nextAlphanumeric(256)))
         .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
-        .setServerGuid(messageGuid.toString())
-        .setDestinationServiceId(UUID.randomUUID().toString())
+        .setServerGuid(UUIDUtil.toByteString(messageGuid))
+        .setDestinationServiceId(new AciServiceIdentifier(UUID.randomUUID()).toCompactByteString())
         .setEphemeral(ephemeral)
         .build();
   }

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagePersisterTest.java

@@ -55,11 +55,12 @@ import org.mockito.stubbing.Answer;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfiguration;
 import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicMessagePersisterConfiguration;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
+import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.identity.IdentityType;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
 import org.whispersystems.textsecuregcm.tests.util.DevicesHelper;
 import org.whispersystems.textsecuregcm.util.TestClock;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Scheduler;
@@ -132,7 +133,7 @@ class MessagePersisterTest {
     messageDeliveryScheduler = Schedulers.newBoundedElastic(10, 10_000, "messageDelivery");
     persistQueueScheduler = Schedulers.newBoundedElastic(10, 10_000, "persistQueue");
     messagesCache = spy(new MessagesCache(REDIS_CLUSTER_EXTENSION.getRedisCluster(),
-        messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), CLOCK, mock(ExperimentEnrollmentManager.class)));
+        messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), CLOCK));
     messagePersister = new MessagePersister(messagesCache,
         messagesManager,
         accountsManager,
@@ -154,7 +155,7 @@ class MessagePersisterTest {
       messagesDynamoDb.store(messages, destinationUuid, destinationDevice);
 
       for (final MessageProtos.Envelope message : messages) {
-        messagesCache.remove(destinationUuid, destinationDevice.getId(), UUID.fromString(message.getServerGuid())).get();
+        messagesCache.remove(destinationUuid, destinationDevice.getId(), UUIDUtil.fromByteString(message.getServerGuid())).get();
       }
 
       return messages.size();
@@ -476,7 +477,7 @@ class MessagePersisterTest {
         .toList();
     final long cacheSize = cachedMessages.stream().mapToLong(MessageProtos.Envelope::getSerializedSize).sum();
     for (final MessageProtos.Envelope envelope : cachedMessages) {
-      messagesCache.insert(UUID.fromString(envelope.getServerGuid()), DESTINATION_ACCOUNT_UUID, Device.PRIMARY_ID, envelope).join();
+      messagesCache.insert(UUIDUtil.fromByteString(envelope.getServerGuid()), DESTINATION_ACCOUNT_UUID, Device.PRIMARY_ID, envelope).join();
     }
 
     final long expectedClearedBytes = (long) (cacheSize * EXTRA_ROOM_RATIO);
@@ -575,12 +576,12 @@ class MessagePersisterTest {
 
   private MessageProtos.Envelope generateMessage(UUID accountUuid, UUID messageGuid, long messageTimestamp, int contentSize) {
     return MessageProtos.Envelope.newBuilder()
-        .setDestinationServiceId(accountUuid.toString())
+        .setDestinationServiceId(new AciServiceIdentifier(accountUuid).toCompactByteString())
         .setClientTimestamp(messageTimestamp)
         .setServerTimestamp(messageTimestamp)
         .setContent(ByteString.copyFromUtf8(RandomStringUtils.secure().nextAlphanumeric(contentSize)))
         .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
-        .setServerGuid(messageGuid.toString())
+        .setServerGuid(UUIDUtil.toByteString(messageGuid))
         .build();
   }
 }

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesCacheGetItemsScriptTest.java

@@ -21,9 +21,9 @@ import java.util.concurrent.ScheduledExecutorService;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
 import org.whispersystems.textsecuregcm.redis.ClusterLuaScript;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 class MessagesCacheGetItemsScriptTest {
 
@@ -38,10 +38,10 @@ class MessagesCacheGetItemsScriptTest {
 
     final UUID destinationUuid = UUID.randomUUID();
     final byte deviceId = 1;
-    final String serverGuid = UUID.randomUUID().toString();
+    final UUID serverGuid = UUID.randomUUID();
     final MessageProtos.Envelope envelope1 = MessageProtos.Envelope.newBuilder()
         .setServerTimestamp(Instant.now().getEpochSecond())
-        .setServerGuid(serverGuid)
+        .setServerGuid(UUIDUtil.toByteString(serverGuid))
         .build();
 
     insertScript.executeAsync(destinationUuid, deviceId, envelope1).toCompletableFuture().join();
@@ -54,11 +54,9 @@ class MessagesCacheGetItemsScriptTest {
 
     assertNotNull(messageAndScores);
     assertEquals(2, messageAndScores.size());
-    final MessageProtos.Envelope resultEnvelope =
-        EnvelopeUtil.expand(MessageProtos.Envelope.parseFrom(messageAndScores.getFirst()),
-            mock(ExperimentEnrollmentManager.class));
+    final MessageProtos.Envelope resultEnvelope = MessageProtos.Envelope.parseFrom(messageAndScores.getFirst());
 
-    assertEquals(serverGuid, resultEnvelope.getServerGuid());
+    assertEquals(serverGuid, UUIDUtil.fromByteString(resultEnvelope.getServerGuid()));
   }
 
   @Test

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesCacheInsertScriptTest.java

@@ -25,6 +25,7 @@ import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.push.RedisMessageAvailabilityManager;
 import org.whispersystems.textsecuregcm.redis.FaultTolerantPubSubClusterConnection;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 class MessagesCacheInsertScriptTest {
 
@@ -40,26 +41,25 @@ class MessagesCacheInsertScriptTest {
     final byte deviceId = 1;
     final MessageProtos.Envelope envelope1 = MessageProtos.Envelope.newBuilder()
         .setServerTimestamp(Instant.now().getEpochSecond())
-        .setServerGuid(UUID.randomUUID().toString())
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
         .build();
 
     insertScript.executeAsync(destinationUuid, deviceId, envelope1).toCompletableFuture().join();
 
-    assertEquals(List.of(EnvelopeUtil.compress(envelope1)), getStoredMessages(destinationUuid, deviceId));
+    assertEquals(List.of(envelope1), getStoredMessages(destinationUuid, deviceId));
 
     final MessageProtos.Envelope envelope2 = MessageProtos.Envelope.newBuilder()
         .setServerTimestamp(Instant.now().getEpochSecond())
-        .setServerGuid(UUID.randomUUID().toString())
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
         .build();
 
     insertScript.executeAsync(destinationUuid, deviceId, envelope2).toCompletableFuture().join();
 
-    assertEquals(List.of(EnvelopeUtil.compress(envelope1), EnvelopeUtil.compress(envelope2)),
-        getStoredMessages(destinationUuid, deviceId));
+    assertEquals(List.of(envelope1, envelope2), getStoredMessages(destinationUuid, deviceId));
 
     insertScript.executeAsync(destinationUuid, deviceId, envelope1).toCompletableFuture().join();
 
-    assertEquals(List.of(EnvelopeUtil.compress(envelope1), EnvelopeUtil.compress(envelope2)),
+    assertEquals(List.of(envelope1, envelope2),
         getStoredMessages(destinationUuid, deviceId),
         "Messages with same GUID should be deduplicated");
   }
@@ -95,7 +95,7 @@ class MessagesCacheInsertScriptTest {
 
     assertFalse(insertScript.executeAsync(destinationUuid, deviceId, MessageProtos.Envelope.newBuilder()
             .setServerTimestamp(Instant.now().getEpochSecond())
-            .setServerGuid(UUID.randomUUID().toString())
+            .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
             .build())
         .toCompletableFuture()
         .join());
@@ -108,7 +108,7 @@ class MessagesCacheInsertScriptTest {
 
     assertTrue(insertScript.executeAsync(destinationUuid, deviceId, MessageProtos.Envelope.newBuilder()
             .setServerTimestamp(Instant.now().getEpochSecond())
-            .setServerGuid(UUID.randomUUID().toString())
+            .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
             .build())
         .toCompletableFuture()
         .join());

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesCacheRemoveByGuidScriptTest.java

@@ -35,7 +35,7 @@ class MessagesCacheRemoveByGuidScriptTest {
     final UUID serverGuid = UUID.randomUUID();
     final MessageProtos.Envelope envelope1 = MessageProtos.Envelope.newBuilder()
         .setServerTimestamp(Instant.now().getEpochSecond())
-        .setServerGuid(serverGuid.toString())
+        .setServerGuid(UUIDUtil.toByteString(serverGuid))
         .build();
 
     insertScript.executeAsync(destinationUuid, deviceId, envelope1).toCompletableFuture().join();
@@ -52,6 +52,6 @@ class MessagesCacheRemoveByGuidScriptTest {
 
     final MessageProtos.Envelope resultMessage = MessageProtos.Envelope.parseFrom(removedMessages.getFirst());
 
-    assertEquals(serverGuid, UUIDUtil.fromByteString(resultMessage.getServerGuidBinary()));
+    assertEquals(serverGuid, UUIDUtil.fromByteString(resultMessage.getServerGuid()));
   }
 }

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesCacheRemoveQueueScriptTest.java

@@ -18,6 +18,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 class MessagesCacheRemoveQueueScriptTest {
 
@@ -35,7 +36,7 @@ class MessagesCacheRemoveQueueScriptTest {
     final byte deviceId = 1;
     final MessageProtos.Envelope envelope1 = MessageProtos.Envelope.newBuilder()
         .setServerTimestamp(Instant.now().getEpochSecond())
-        .setServerGuid(UUID.randomUUID().toString())
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
         .build();
 
     insertScript.executeAsync(destinationUuid, deviceId, envelope1).toCompletableFuture().join();

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesCacheTest.java

@@ -71,12 +71,12 @@ import org.junit.jupiter.params.provider.ValueSource;
 import org.reactivestreams.Publisher;
 import org.signal.libsignal.protocol.SealedSenderMultiRecipientMessage;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
 import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
 import org.whispersystems.textsecuregcm.redis.FaultTolerantRedisClusterClient;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
 import org.whispersystems.textsecuregcm.tests.util.RedisClusterHelper;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.publisher.Flux;
 import reactor.core.scheduler.Scheduler;
 import reactor.core.scheduler.Schedulers;
@@ -110,7 +110,7 @@ class MessagesCacheTest {
       resubscribeRetryExecutorService = Executors.newSingleThreadScheduledExecutor();
       messageDeliveryScheduler = Schedulers.newBoundedElastic(10, 10_000, "messageDelivery");
       messagesCache = new MessagesCache(REDIS_CLUSTER_EXTENSION.getRedisCluster(),
-          messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC(), mock(ExperimentEnrollmentManager.class));
+          messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC());
     }
 
     @AfterEach
@@ -176,21 +176,21 @@ class MessagesCacheTest {
       }
 
       assertEquals(Collections.emptyList(), messagesCache.remove(DESTINATION_UUID, DESTINATION_DEVICE_ID,
-          messagesToRemove.stream().map(message -> UUID.fromString(message.getServerGuid()))
+          messagesToRemove.stream().map(message -> UUIDUtil.fromByteString(message.getServerGuid()))
               .collect(Collectors.toList())).get(5, TimeUnit.SECONDS));
 
       for (final MessageProtos.Envelope message : messagesToRemove) {
-        messagesCache.insert(UUID.fromString(message.getServerGuid()), DESTINATION_UUID, DESTINATION_DEVICE_ID,
+        messagesCache.insert(UUIDUtil.fromByteString(message.getServerGuid()), DESTINATION_UUID, DESTINATION_DEVICE_ID,
             message).join();
       }
 
       for (final MessageProtos.Envelope message : messagesToPreserve) {
-        messagesCache.insert(UUID.fromString(message.getServerGuid()), DESTINATION_UUID, DESTINATION_DEVICE_ID,
+        messagesCache.insert(UUIDUtil.fromByteString(message.getServerGuid()), DESTINATION_UUID, DESTINATION_DEVICE_ID,
             message).join();
       }
 
       final List<RemovedMessage> removedMessages = messagesCache.remove(DESTINATION_UUID, DESTINATION_DEVICE_ID,
-          messagesToRemove.stream().map(message -> UUID.fromString(message.getServerGuid()))
+          messagesToRemove.stream().map(message -> UUIDUtil.fromByteString(message.getServerGuid()))
               .collect(Collectors.toList())).get(5, TimeUnit.SECONDS);
 
       assertEquals(messagesToRemove.stream().map(RemovedMessage::fromEnvelope).toList(), removedMessages);
@@ -227,7 +227,7 @@ class MessagesCacheTest {
       for (final MessageProtos.Envelope message : expectedMessages) {
         assertEquals(expectedOldestTimestamp,
             messagesCache.getEarliestUndeliveredTimestamp(DESTINATION_UUID, DESTINATION_DEVICE_ID).block());
-        messagesCache.remove(DESTINATION_UUID, DESTINATION_DEVICE_ID, UUID.fromString(message.getServerGuid())).join();
+        messagesCache.remove(DESTINATION_UUID, DESTINATION_DEVICE_ID, UUIDUtil.fromByteString(message.getServerGuid())).join();
         expectedOldestTimestamp += 1;
       }
       assertNull(messagesCache.getEarliestUndeliveredTimestamp(DESTINATION_UUID, DESTINATION_DEVICE_ID).block());
@@ -252,7 +252,7 @@ class MessagesCacheTest {
       messagesCache.remove(DESTINATION_UUID, DESTINATION_DEVICE_ID,
           expectedMessages.stream()
               .map(MessageProtos.Envelope::getServerGuid)
-              .map(UUID::fromString)
+              .map(UUIDUtil::fromByteString)
               .collect(Collectors.toList()));
 
       final UUID message1Guid = UUID.randomUUID();
@@ -385,7 +385,7 @@ class MessagesCacheTest {
       }
 
       final MessagesCache messagesCache = new MessagesCache(REDIS_CLUSTER_EXTENSION.getRedisCluster(),
-          messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), cacheClock, mock(ExperimentEnrollmentManager.class));
+          messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), cacheClock);
 
       final List<MessageProtos.Envelope> actualMessages = Flux.from(
               messagesCache.get(DESTINATION_UUID, DESTINATION_DEVICE_ID))
@@ -406,7 +406,7 @@ class MessagesCacheTest {
         // delete all of these messages and call `getAll()`, to confirm that ephemeral messages have been discarded
         CompletableFuture.allOf(actualMessages.stream()
                 .map(message -> messagesCache.remove(DESTINATION_UUID, DESTINATION_DEVICE_ID,
-                    UUID.fromString(message.getServerGuid())))
+                    UUIDUtil.fromByteString(message.getServerGuid())))
                 .toArray(CompletableFuture<?>[]::new))
             .get(5, TimeUnit.SECONDS);
 
@@ -592,7 +592,7 @@ class MessagesCacheTest {
       } else {
         assertEquals(1, messages.size());
 
-        assertEquals(guid, UUID.fromString(messages.getFirst().getServerGuid()));
+        assertEquals(guid, UUIDUtil.fromByteString(messages.getFirst().getServerGuid()));
         assertFalse(messages.getFirst().hasSharedMrmKey());
         final SealedSenderMultiRecipientMessage.Recipient recipient = mrm.getRecipients()
             .get(destinationServiceId.toLibsignal());
@@ -672,7 +672,7 @@ class MessagesCacheTest {
 
           default -> throw new IllegalStateException();
         };
-        messagesCache.insert(UUID.fromString(messageToInsert.getServerGuid()), destinationUuid, deviceId, messageToInsert).join();
+        messagesCache.insert(UUIDUtil.fromByteString(messageToInsert.getServerGuid()), destinationUuid, deviceId, messageToInsert).join();
       }
       long actualQueueSize = messagesCache.estimatePersistedQueueSizeBytes(destinationUuid, deviceId).join();
       assertEquals(expectedQueueSize, actualQueueSize);
@@ -730,7 +730,7 @@ class MessagesCacheTest {
       }
 
       assertEquals(message.toBuilder()
-              .setServerGuid(messageGuid.toString())
+              .setServerGuid(UUIDUtil.toByteString(messageGuid))
               .build(),
           messages.getFirst());
     }
@@ -765,7 +765,7 @@ class MessagesCacheTest {
       messageDeliveryScheduler = Schedulers.newBoundedElastic(10, 10_000, "messageDelivery");
 
       messagesCache = new MessagesCache(mockCluster, messageDeliveryScheduler,
-          Executors.newSingleThreadExecutor(), mock(ScheduledExecutorService.class), Clock.systemUTC(), mock(ExperimentEnrollmentManager.class));
+          Executors.newSingleThreadExecutor(), mock(ScheduledExecutorService.class), Clock.systemUTC());
     }
 
     @AfterEach
@@ -1003,13 +1003,13 @@ class MessagesCacheTest {
         .setServerTimestamp(timestamp)
         .setContent(ByteString.copyFromUtf8(RandomStringUtils.secure().nextAlphanumeric(256)))
         .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
-        .setServerGuid(messageGuid.toString())
-        .setDestinationServiceId(destinationServiceId.toServiceIdentifierString())
+        .setServerGuid(UUIDUtil.toByteString(messageGuid))
+        .setDestinationServiceId(destinationServiceId.toCompactByteString())
         .setEphemeral(ephemeral);
 
     if (!sealedSender) {
       envelopeBuilder.setSourceDevice(random.nextInt(Device.MAXIMUM_DEVICE_ID) + 1)
-          .setSourceServiceId(UUID.randomUUID().toString());
+          .setSourceServiceId(new AciServiceIdentifier(UUID.randomUUID()).toCompactByteString());
     }
 
     return envelopeBuilder.build();

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesDynamoDbTest.java

@@ -6,9 +6,9 @@
 package org.whispersystems.textsecuregcm.storage;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Mockito.mock;
 
 import com.google.protobuf.ByteString;
+import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
@@ -26,10 +26,10 @@ import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 import org.reactivestreams.Publisher;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
+import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.storage.DynamoDbExtensionSchema.Tables;
 import org.whispersystems.textsecuregcm.tests.util.DevicesHelper;
-import org.whispersystems.textsecuregcm.tests.util.MessageHelper;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.core.publisher.Flux;
 import reactor.test.StepVerifier;
 
@@ -47,19 +47,19 @@ class MessagesDynamoDbTest {
     builder.setType(MessageProtos.Envelope.Type.UNIDENTIFIED_SENDER);
     builder.setClientTimestamp(123456789L);
     builder.setContent(ByteString.copyFrom(new byte[]{(byte) 0xDE, (byte) 0xAD, (byte) 0xBE, (byte) 0xEF}));
-    builder.setServerGuid(UUID.randomUUID().toString());
+    builder.setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()));
     builder.setServerTimestamp(serverTimestamp);
-    builder.setDestinationServiceId(UUID.randomUUID().toString());
+    builder.setDestinationServiceId(UUIDUtil.toByteString(UUID.randomUUID()));
 
     MESSAGE1 = builder.build();
 
     builder.setType(MessageProtos.Envelope.Type.CIPHERTEXT);
-    builder.setSourceServiceId(UUID.randomUUID().toString());
+    builder.setSourceServiceId(UUIDUtil.toByteString(UUID.randomUUID()));
     builder.setSourceDevice(1);
     builder.setContent(ByteString.copyFromUtf8("MOO"));
-    builder.setServerGuid(UUID.randomUUID().toString());
+    builder.setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()));
     builder.setServerTimestamp(serverTimestamp + 1);
-    builder.setDestinationServiceId(UUID.randomUUID().toString());
+    builder.setDestinationServiceId(UUIDUtil.toByteString(UUID.randomUUID()));
 
     MESSAGE2 = builder.build();
 
@@ -67,9 +67,9 @@ class MessagesDynamoDbTest {
     builder.clearSourceDevice();
     builder.clearSourceDevice();
     builder.setContent(ByteString.copyFromUtf8("COW"));
-    builder.setServerGuid(UUID.randomUUID().toString());
+    builder.setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()));
     builder.setServerTimestamp(serverTimestamp);  // Test same millisecond arrival for two different messages
-    builder.setDestinationServiceId(UUID.randomUUID().toString());
+    builder.setDestinationServiceId(UUIDUtil.toByteString(UUID.randomUUID()));
 
     MESSAGE3 = builder.build();
   }
@@ -85,7 +85,7 @@ class MessagesDynamoDbTest {
     messageDeletionExecutorService = Executors.newSingleThreadExecutor();
     messagesDynamoDb = new MessagesDynamoDb(DYNAMO_DB_EXTENSION.getDynamoDbClient(),
         DYNAMO_DB_EXTENSION.getDynamoDbAsyncClient(), Tables.MESSAGES.tableName(), Duration.ofDays(14),
-        messageDeletionExecutorService, mock(ExperimentEnrollmentManager.class));
+        messageDeletionExecutorService);
   }
 
   @AfterEach
@@ -107,8 +107,14 @@ class MessagesDynamoDbTest {
     final List<MessageProtos.Envelope> messagesStored = load(destinationUuid, destinationDevice,
         MessagesDynamoDb.RESULT_SET_CHUNK_SIZE);
     assertThat(messagesStored).isNotNull().hasSize(3);
+
+    // Danger: `UUID#compareTo` does NOT do what you might expect because it uses
+    // `Long.compare(a.mostSignificantBits(), b.mostSignificantBits())`, which means that a UUID whose binary
+    // representation is lexicographically "greater than" another UUID might wind up "less than" the other UUID if its
+    // most significant bit is `1`, which would cause `UUID#compareTo` to treat it as a negative number. To avoid that
+    // surprise (and match DynamoDB's lexicographical sorting), we just do string ordering.
     final MessageProtos.Envelope firstMessage =
-        MESSAGE1.getServerGuid().compareTo(MESSAGE3.getServerGuid()) < 0 ? MESSAGE1 : MESSAGE3;
+        UUIDUtil.fromByteString(MESSAGE1.getServerGuid()).toString().compareTo(UUIDUtil.fromByteString(MESSAGE3.getServerGuid()).toString()) < 0 ? MESSAGE1 : MESSAGE3;
     final MessageProtos.Envelope secondMessage = firstMessage == MESSAGE1 ? MESSAGE3 : MESSAGE1;
     assertThat(messagesStored).element(0).isEqualTo(firstMessage);
     assertThat(messagesStored).element(1).isEqualTo(secondMessage);
@@ -124,8 +130,7 @@ class MessagesDynamoDbTest {
 
     final List<MessageProtos.Envelope> messages = new ArrayList<>(messageCount);
     for (int i = 0; i < messageCount; i++) {
-      messages.add(MessageHelper.createMessage(UUID.randomUUID(), Device.PRIMARY_ID, destinationUuid, (i + 1L) * 1000,
-          "message " + i));
+      messages.add(createMessage(UUID.randomUUID(), Device.PRIMARY_ID, destinationUuid, (i + 1L) * 1000, "message " + i));
     }
 
     messagesDynamoDb.store(messages, destinationUuid, destinationDevice);
@@ -158,8 +163,7 @@ class MessagesDynamoDbTest {
 
     final List<MessageProtos.Envelope> messages = new ArrayList<>(messageCount);
     for (int i = 0; i < messageCount; i++) {
-      messages.add(MessageHelper.createMessage(UUID.randomUUID(), Device.PRIMARY_ID, destinationUuid, (i + 1L) * 1000,
-          "message " + i));
+      messages.add(createMessage(UUID.randomUUID(), Device.PRIMARY_ID, destinationUuid, (i + 1L) * 1000, "message " + i));
     }
 
     messagesDynamoDb.store(messages, destinationUuid, destinationDevice);
@@ -207,7 +211,7 @@ class MessagesDynamoDbTest {
         .hasSize(1).element(0).isEqualTo(MESSAGE2);
 
     messagesDynamoDb.deleteMessage(secondDestinationUuid, primary,
-        UUID.fromString(MESSAGE2.getServerGuid()), MESSAGE2.getServerTimestamp()).get(1, TimeUnit.SECONDS);
+        UUIDUtil.fromByteString(MESSAGE2.getServerGuid()), MESSAGE2.getServerTimestamp()).get(1, TimeUnit.SECONDS);
 
     assertThat(load(destinationUuid, primary, MessagesDynamoDb.RESULT_SET_CHUNK_SIZE)).isNotNull().hasSize(1)
         .element(0).isEqualTo(MESSAGE1);
@@ -236,7 +240,7 @@ class MessagesDynamoDbTest {
     assertThat(load(destinationUuid, primary, MessagesDynamoDb.RESULT_SET_CHUNK_SIZE))
         .as("load should return all messages stored").containsOnly(MESSAGE1, MESSAGE2);
 
-    messagesDynamoDb.deleteMessage(destinationUuid, primary, UUID.fromString(MESSAGE1.getServerGuid()), MESSAGE1.getServerTimestamp())
+    messagesDynamoDb.deleteMessage(destinationUuid, primary, UUIDUtil.fromByteString(MESSAGE1.getServerGuid()), MESSAGE1.getServerTimestamp())
         .get(1, TimeUnit.SECONDS);
     assertThat(load(destinationUuid, primary, MessagesDynamoDb.RESULT_SET_CHUNK_SIZE))
         .as("deleting message by guid and timestamp should work").containsExactly(MESSAGE2);
@@ -273,8 +277,8 @@ class MessagesDynamoDbTest {
     {
       final MessageProtos.Envelope nonUrgentMessage = MessageProtos.Envelope.newBuilder()
           .setUrgent(false)
-          .setServerGuid(UUID.randomUUID().toString())
-          .setDestinationServiceId(destinationUuid.toString())
+          .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
+          .setDestinationServiceId(new AciServiceIdentifier(destinationUuid).toCompactByteString())
           .setServerTimestamp(serverTimestamp++)
           .build();
 
@@ -289,17 +293,17 @@ class MessagesDynamoDbTest {
       for (int i = 0; i < MessagesDynamoDb.MAY_HAVE_URGENT_MESSAGES_QUERY_LIMIT * 5; i++) {
         messages.add(MessageProtos.Envelope.newBuilder()
             .setUrgent(false)
-            .setServerGuid(UUID.randomUUID().toString())
-            .setDestinationServiceId(destinationUuid.toString())
-                .setServerTimestamp(serverTimestamp++)
+            .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
+            .setDestinationServiceId(new AciServiceIdentifier(destinationUuid).toCompactByteString())
+            .setServerTimestamp(serverTimestamp++)
             .build());
       }
 
       // and one urgent message
       messages.add(MessageProtos.Envelope.newBuilder()
           .setUrgent(true)
-          .setServerGuid(UUID.randomUUID().toString())
-          .setDestinationServiceId(destinationUuid.toString())
+          .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
+          .setDestinationServiceId(new AciServiceIdentifier(destinationUuid).toCompactByteString())
           .setServerTimestamp(serverTimestamp++)
           .build());
 
@@ -308,4 +312,22 @@ class MessagesDynamoDbTest {
 
     assertThat(messagesDynamoDb.mayHaveUrgentMessages(destinationUuid, destinationDevice).join()).isTrue();
   }
+
+  private static MessageProtos.Envelope createMessage(final UUID senderUuid,
+      final byte senderDeviceId,
+      final UUID destinationUuid,
+      long timestamp,
+      final String content) {
+
+    return MessageProtos.Envelope.newBuilder()
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
+        .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
+        .setClientTimestamp(timestamp)
+        .setServerTimestamp(0)
+        .setSourceServiceId(new AciServiceIdentifier(senderUuid).toCompactByteString())
+        .setSourceDevice(senderDeviceId)
+        .setDestinationServiceId(new AciServiceIdentifier(destinationUuid).toCompactByteString())
+        .setContent(ByteString.copyFrom(content.getBytes(StandardCharsets.UTF_8)))
+        .build();
+  }
 }

service/src/test/java/org/whispersystems/textsecuregcm/storage/MessagesManagerTest.java

@@ -66,7 +66,7 @@ class MessagesManagerTest {
   void insert() {
     final UUID sourceAci = UUID.randomUUID();
     final Envelope message = Envelope.newBuilder()
-        .setSourceServiceId(sourceAci.toString())
+        .setSourceServiceId(new AciServiceIdentifier(sourceAci).toCompactByteString())
         .build();
 
     final UUID destinationUuid = UUID.randomUUID();
@@ -76,7 +76,7 @@ class MessagesManagerTest {
     verify(reportMessageManager).store(eq(sourceAci.toString()), any(UUID.class));
 
     final Envelope syncMessage = Envelope.newBuilder(message)
-        .setSourceServiceId(destinationUuid.toString())
+        .setSourceServiceId(new AciServiceIdentifier(destinationUuid).toCompactByteString())
         .build();
 
     messagesManager.insert(destinationUuid, Map.of(Device.PRIMARY_ID, syncMessage));
@@ -170,17 +170,17 @@ class MessagesManagerTest {
     verify(messagesCache).insert(any(),
         eq(singleDeviceAccountAciServiceIdentifier.uuid()),
         eq(Device.PRIMARY_ID),
-        eq(prototypeExpectedMessage.toBuilder().setDestinationServiceId(singleDeviceAccountAciServiceIdentifier.toServiceIdentifierString()).build()));
+        eq(prototypeExpectedMessage.toBuilder().setDestinationServiceId(singleDeviceAccountAciServiceIdentifier.toCompactByteString()).build()));
 
     verify(messagesCache).insert(any(),
         eq(singleDeviceAccountAciServiceIdentifier.uuid()),
         eq(Device.PRIMARY_ID),
-        eq(prototypeExpectedMessage.toBuilder().setDestinationServiceId(singleDeviceAccountPniServiceIdentifier.toServiceIdentifierString()).build()));
+        eq(prototypeExpectedMessage.toBuilder().setDestinationServiceId(singleDeviceAccountPniServiceIdentifier.toCompactByteString()).build()));
 
     verify(messagesCache).insert(any(),
         eq(multiDeviceAccountAciServiceIdentifier.uuid()),
         eq((byte) (Device.PRIMARY_ID + 1)),
-        eq(prototypeExpectedMessage.toBuilder().setDestinationServiceId(multiDeviceAccountAciServiceIdentifier.toServiceIdentifierString()).build()));
+        eq(prototypeExpectedMessage.toBuilder().setDestinationServiceId(multiDeviceAccountAciServiceIdentifier.toCompactByteString()).build()));
 
     verify(messagesCache, never()).insert(any(),
         eq(unresolvedAccountAciServiceIdentifier.uuid()),

service/src/test/java/org/whispersystems/textsecuregcm/storage/RedisDynamoDbMessagePublisherTest.java

@@ -37,11 +37,11 @@ import org.junit.jupiter.api.extension.RegisterExtension;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
-import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
 import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.identity.ServiceIdentifier;
 import org.whispersystems.textsecuregcm.push.RedisMessageAvailabilityManager;
 import org.whispersystems.textsecuregcm.redis.RedisClusterExtension;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import reactor.adapter.JdkFlowAdapter;
 import reactor.core.Disposable;
 import reactor.core.scheduler.Scheduler;
@@ -82,11 +82,10 @@ class RedisDynamoDbMessagePublisherTest {
         DYNAMO_DB_EXTENSION.getDynamoDbAsyncClient(),
         DynamoDbExtensionSchema.Tables.MESSAGES.tableName(),
         Duration.ofDays(14),
-        sharedExecutorService,
-        mock(ExperimentEnrollmentManager.class));
+        sharedExecutorService);
 
     messagesCache = new MessagesCache(REDIS_CLUSTER_EXTENSION.getRedisCluster(),
-        messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC(), mock(ExperimentEnrollmentManager.class));
+        messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC());
 
     redisMessageAvailabilityManager = mock(RedisMessageAvailabilityManager.class);
 
@@ -398,7 +397,7 @@ class RedisDynamoDbMessagePublisherTest {
   }
 
   private MessageProtos.Envelope insertRedisMessage(final MessageProtos.Envelope message) {
-    messagesCache.insert(UUID.fromString(message.getServerGuid()),
+    messagesCache.insert(UUIDUtil.fromByteString(message.getServerGuid()),
         DESTINATION_SERVICE_IDENTIFIER.uuid(),
         destinationDevice.getId(),
         message)
@@ -408,7 +407,7 @@ class RedisDynamoDbMessagePublisherTest {
   }
 
   private void deleteRedisMessage(final MessageProtos.Envelope message) {
-    messagesCache.remove(DESTINATION_SERVICE_IDENTIFIER.uuid(), destinationDevice.getId(), UUID.fromString(message.getServerGuid())).join();
+    messagesCache.remove(DESTINATION_SERVICE_IDENTIFIER.uuid(), destinationDevice.getId(), UUIDUtil.fromByteString(message.getServerGuid())).join();
   }
 
   private MessageProtos.Envelope insertDynamoDbMessage(final MessageProtos.Envelope message) {
@@ -420,7 +419,7 @@ class RedisDynamoDbMessagePublisherTest {
   private void deleteDynamoDbMessage(final MessageProtos.Envelope message) {
     messagesDynamoDb.deleteMessage(DESTINATION_SERVICE_IDENTIFIER.uuid(),
         destinationDevice,
-        UUID.fromString(message.getServerGuid()),
+        UUIDUtil.fromByteString(message.getServerGuid()),
         message.getServerTimestamp())
         .join();
   }
@@ -434,8 +433,8 @@ class RedisDynamoDbMessagePublisherTest {
         .setServerTimestamp(timestamp)
         .setContent(ByteString.copyFromUtf8(RandomStringUtils.secure().nextAlphanumeric(256)))
         .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
-        .setServerGuid(UUID.randomUUID().toString())
-        .setDestinationServiceId(DESTINATION_SERVICE_IDENTIFIER.toServiceIdentifierString());
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
+        .setDestinationServiceId(DESTINATION_SERVICE_IDENTIFIER.toCompactByteString());
 
     return envelopeBuilder.build();
   }

service/src/test/java/org/whispersystems/textsecuregcm/storage/RedisDynamoDbMessageStreamTest.java

@@ -20,6 +20,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 
 class RedisDynamoDbMessageStreamTest {
 
@@ -57,7 +58,7 @@ class RedisDynamoDbMessageStreamTest {
   @Test
   void acknowledgeMessageDynamoDb() {
     final MessageProtos.Envelope message = generateMessage();
-    final UUID messageGuid = UUID.fromString(message.getServerGuid());
+    final UUID messageGuid = UUIDUtil.fromByteString(message.getServerGuid());
     final long serverTimestamp = message.getServerTimestamp();
 
     when(messagesDynamoDb.deleteMessage(ACCOUNT_IDENTIFIER, device, messageGuid, serverTimestamp))
@@ -72,7 +73,7 @@ class RedisDynamoDbMessageStreamTest {
   @Test
   void acknowledgeMessageRedis() {
     final MessageProtos.Envelope message = generateMessage();
-    final UUID messageGuid = UUID.fromString(message.getServerGuid());
+    final UUID messageGuid = UUIDUtil.fromByteString(message.getServerGuid());
 
     when(messagesCache.remove(ACCOUNT_IDENTIFIER, DEVICE_ID, messageGuid))
         .thenReturn(CompletableFuture.completedFuture(Optional.of(RemovedMessage.fromEnvelope(message))));
@@ -85,8 +86,8 @@ class RedisDynamoDbMessageStreamTest {
 
   private static MessageProtos.Envelope generateMessage() {
     return MessageProtos.Envelope.newBuilder()
-        .setServerGuid(UUID.randomUUID().toString())
-        .setDestinationServiceId(new AciServiceIdentifier(ACCOUNT_IDENTIFIER).toServiceIdentifierString())
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
+        .setDestinationServiceId(new AciServiceIdentifier(ACCOUNT_IDENTIFIER).toCompactByteString())
         .setServerTimestamp(System.currentTimeMillis())
         .setClientTimestamp(System.currentTimeMillis())
         .setType(MessageProtos.Envelope.Type.CIPHERTEXT)

service/src/test/java/org/whispersystems/textsecuregcm/storage/foundationdb/FoundationDbMessageStoreTest.java

@@ -423,7 +423,7 @@ class FoundationDbMessageStoreTest {
           assertInstanceOf(MessageStreamEntry.Envelope.class, retrievedEntries.get(i));
 
       assertEquals(expectedVersionstamps.get(i),
-          messageGuidCodec.decodeMessageGuid(UUIDUtil.fromByteString(envelopeEntry.message().getServerGuidBinary())));
+          messageGuidCodec.decodeMessageGuid(UUIDUtil.fromByteString(envelopeEntry.message().getServerGuid())));
     }
   }
 
@@ -483,18 +483,18 @@ class FoundationDbMessageStoreTest {
     StepVerifier.create(JdkFlowAdapter.flowPublisherToFlux(messageStream.getMessages()))
         .expectNext(new MessageStreamEntry.Envelope(message1
             .toBuilder()
-            .setServerGuidBinary(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp1)))
+            .setServerGuid(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp1)))
             .build()))
         .expectNext(new MessageStreamEntry.Envelope(message2
             .toBuilder()
-            .setServerGuidBinary(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp2)))
+            .setServerGuid(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp2)))
             .build()))
         .expectNext(new MessageStreamEntry.QueueEmpty())
         // Trigger insertion of another message
         .then(latch::countDown)
         .expectNextMatches(entry -> entry.equals(new MessageStreamEntry.Envelope(message3
             .toBuilder()
-            .setServerGuidBinary(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp3.join())))
+            .setServerGuid(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(versionstamp3.join())))
             .build())))
         .verifyTimeout(Duration.ofSeconds(3));
   }
@@ -602,7 +602,7 @@ class FoundationDbMessageStoreTest {
 
     assertEquals(expectedRedeliveredVersionstamps, retrievedEntries.stream()
         .filter(e -> e instanceof MessageStreamEntry.Envelope)
-        .map(e -> messageGuidCodec.decodeMessageGuid(UUIDUtil.fromByteString(((MessageStreamEntry.Envelope) e).message().getServerGuidBinary())))
+        .map(e -> messageGuidCodec.decodeMessageGuid(UUIDUtil.fromByteString(((MessageStreamEntry.Envelope) e).message().getServerGuid())))
         .toList());
 
   }
@@ -692,7 +692,7 @@ class FoundationDbMessageStoreTest {
         .then(queueEmptyLatch::countDown)
         .expectNextMatches(entry -> entry.equals(new MessageStreamEntry.Envelope(freshEphemeralMessage
             .toBuilder()
-            .setServerGuidBinary(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(deliveredUnacknowledgedVersionstamp.join())))
+            .setServerGuid(UUIDUtil.toByteString(messageGuidCodec.encodeMessageGuid(deliveredUnacknowledgedVersionstamp.join())))
             .build())))
         .verifyTimeout(Duration.ofSeconds(3));
 

service/src/test/java/org/whispersystems/textsecuregcm/tests/util/MessageHelper.java

@@ -1,28 +0,0 @@
-/*
- * Copyright 2022 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.whispersystems.textsecuregcm.tests.util;
-
-import com.google.protobuf.ByteString;
-import java.nio.charset.StandardCharsets;
-import java.util.UUID;
-import org.whispersystems.textsecuregcm.entities.MessageProtos;
-
-public class MessageHelper {
-
-  public static MessageProtos.Envelope createMessage(UUID senderUuid, final byte senderDeviceId, UUID destinationUuid,
-      long timestamp, String content) {
-    return MessageProtos.Envelope.newBuilder()
-        .setServerGuid(UUID.randomUUID().toString())
-        .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
-        .setClientTimestamp(timestamp)
-        .setServerTimestamp(0)
-        .setSourceServiceId(senderUuid.toString())
-        .setSourceDevice(senderDeviceId)
-        .setDestinationServiceId(destinationUuid.toString())
-        .setContent(ByteString.copyFrom(content.getBytes(StandardCharsets.UTF_8)))
-        .build();
-  }
-}

service/src/test/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionIntegrationTest.java

@@ -49,6 +49,7 @@ import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfigurati
 import org.whispersystems.textsecuregcm.entities.MessageProtos;
 import org.whispersystems.textsecuregcm.entities.MessageProtos.Envelope;
 import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
+import org.whispersystems.textsecuregcm.identity.AciServiceIdentifier;
 import org.whispersystems.textsecuregcm.identity.IdentityType;
 import org.whispersystems.textsecuregcm.limits.MessageDeliveryLoopMonitor;
 import org.whispersystems.textsecuregcm.metrics.MessageMetrics;
@@ -67,6 +68,7 @@ import org.whispersystems.textsecuregcm.storage.MessagesCache;
 import org.whispersystems.textsecuregcm.storage.MessagesDynamoDb;
 import org.whispersystems.textsecuregcm.storage.MessagesManager;
 import org.whispersystems.textsecuregcm.storage.ReportMessageManager;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import org.whispersystems.websocket.WebSocketClient;
 import org.whispersystems.websocket.messages.WebSocketResponseMessage;
 import reactor.core.publisher.Mono;
@@ -106,10 +108,10 @@ class WebSocketConnectionIntegrationTest {
     when(dynamicConfigurationManager.getConfiguration()).thenReturn(new DynamicConfiguration());
 
     messagesCache = new MessagesCache(REDIS_CLUSTER_EXTENSION.getRedisCluster(),
-        messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC(), mock(ExperimentEnrollmentManager.class));
+        messageDeliveryScheduler, sharedExecutorService, mock(ScheduledExecutorService.class), Clock.systemUTC());
     messagesDynamoDb = new MessagesDynamoDb(DYNAMO_DB_EXTENSION.getDynamoDbClient(),
         DYNAMO_DB_EXTENSION.getDynamoDbAsyncClient(), Tables.MESSAGES.tableName(), Duration.ofDays(7),
-        sharedExecutorService, mock(ExperimentEnrollmentManager.class));
+        sharedExecutorService);
     redisMessageAvailabilityManager = new RedisMessageAvailabilityManager(REDIS_CLUSTER_EXTENSION.getRedisCluster(), sharedExecutorService, sharedExecutorService);
     reportMessageManager = mock(ReportMessageManager.class);
     account = mock(Account.class);
@@ -392,8 +394,8 @@ class WebSocketConnectionIntegrationTest {
         .setServerTimestamp(timestamp)
         .setContent(ByteString.copyFromUtf8(RandomStringUtils.secure().nextAlphanumeric(256)))
         .setType(MessageProtos.Envelope.Type.CIPHERTEXT)
-        .setServerGuid(messageGuid.toString())
-        .setDestinationServiceId(UUID.randomUUID().toString())
+        .setServerGuid(UUIDUtil.toByteString(messageGuid))
+        .setDestinationServiceId(new AciServiceIdentifier(UUID.randomUUID()).toCompactByteString())
         .build();
   }
 }

service/src/test/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionTest.java

@@ -56,6 +56,7 @@ import org.whispersystems.textsecuregcm.storage.Device;
 import org.whispersystems.textsecuregcm.storage.MessageStream;
 import org.whispersystems.textsecuregcm.storage.MessageStreamEntry;
 import org.whispersystems.textsecuregcm.storage.MessagesManager;
+import org.whispersystems.textsecuregcm.util.UUIDUtil;
 import org.whispersystems.websocket.WebSocketClient;
 import org.whispersystems.websocket.messages.WebSocketResponseMessage;
 import reactor.adapter.JdkFlowAdapter;
@@ -177,13 +178,13 @@ class WebSocketConnectionTest {
     verify(receiptSender)
         .sendReceipt(new AciServiceIdentifier(destinationAccountIdentifier),
             deviceId,
-            AciServiceIdentifier.valueOf(successfulMessage.getSourceServiceId()),
+            AciServiceIdentifier.fromByteString(successfulMessage.getSourceServiceId()),
             successfulMessage.getClientTimestamp());
 
     verify(receiptSender)
         .sendReceipt(new AciServiceIdentifier(destinationAccountIdentifier),
             deviceId,
-            AciServiceIdentifier.valueOf(secondSuccessfulMessage.getSourceServiceId()),
+            AciServiceIdentifier.fromByteString(secondSuccessfulMessage.getSourceServiceId()),
             secondSuccessfulMessage.getClientTimestamp());
 
     webSocketConnection.stop();
@@ -253,19 +254,19 @@ class WebSocketConnectionTest {
     verify(receiptSender)
         .sendReceipt(new AciServiceIdentifier(destinationAccountIdentifier),
             deviceId,
-            AciServiceIdentifier.valueOf(successfulMessage.getSourceServiceId()),
+            AciServiceIdentifier.fromByteString(successfulMessage.getSourceServiceId()),
             successfulMessage.getClientTimestamp());
 
     verify(receiptSender, never())
         .sendReceipt(new AciServiceIdentifier(destinationAccountIdentifier),
             deviceId,
-            AciServiceIdentifier.valueOf(failedMessage.getSourceServiceId()),
+            AciServiceIdentifier.fromByteString(failedMessage.getSourceServiceId()),
             failedMessage.getClientTimestamp());
 
     verify(receiptSender, never())
         .sendReceipt(new AciServiceIdentifier(destinationAccountIdentifier),
             deviceId,
-            AciServiceIdentifier.valueOf(secondSuccessfulMessage.getSourceServiceId()),
+            AciServiceIdentifier.fromByteString(secondSuccessfulMessage.getSourceServiceId()),
             secondSuccessfulMessage.getClientTimestamp());
 
     verify(client, timeout(500)).close(eq(1011), anyString());
@@ -572,13 +573,13 @@ class WebSocketConnectionTest {
       final String content) {
 
     return Envelope.newBuilder()
-        .setServerGuid(UUID.randomUUID().toString())
+        .setServerGuid(UUIDUtil.toByteString(UUID.randomUUID()))
         .setType(Envelope.Type.CIPHERTEXT)
         .setClientTimestamp(timestamp)
         .setServerTimestamp(0)
-        .setSourceServiceId(senderUuid.toString())
+        .setSourceServiceId(new AciServiceIdentifier(senderUuid).toCompactByteString())
         .setSourceDevice(SOURCE_DEVICE_ID)
-        .setDestinationServiceId(destinationUuid.toString())
+        .setDestinationServiceId(new AciServiceIdentifier(destinationUuid).toCompactByteString())
         .setContent(ByteString.copyFrom(content.getBytes(StandardCharsets.UTF_8)))
         .build();
   }