diff --git a/js/modules/metadata/CiphertextMessage.js b/js/modules/metadata/CiphertextMessage.js
index 1e2ddb6ea..20274e204 100644
--- a/js/modules/metadata/CiphertextMessage.js
+++ b/js/modules/metadata/CiphertextMessage.js
@@ -11,5 +11,5 @@ module.exports = {
 
   ENCRYPTED_MESSAGE_OVERHEAD: 53,
 
-  LOKI_FRIEND_REQUEST: 101,
+  FALLBACK_MESSAGE: 101,
 };
diff --git a/js/modules/metadata/SecretSessionCipher.js b/js/modules/metadata/SecretSessionCipher.js
index 5f8d38495..3e0166c42 100644
--- a/js/modules/metadata/SecretSessionCipher.js
+++ b/js/modules/metadata/SecretSessionCipher.js
@@ -199,8 +199,8 @@ function _createUnidentifiedSenderMessageContentFromBuffer(serialized) {
     case TypeEnum.PREKEY_MESSAGE:
       type = CiphertextMessage.PREKEY_TYPE;
       break;
-    case TypeEnum.LOKI_FRIEND_REQUEST:
-      type = CiphertextMessage.LOKI_FRIEND_REQUEST;
+    case TypeEnum.FALLBACK_MESSAGE:
+      type = CiphertextMessage.FALLBACK_MESSAGE;
       break;
     default:
       throw new Error(`Unknown type: ${message.type}`);
@@ -226,8 +226,8 @@ function _getProtoMessageType(type) {
       return TypeEnum.MESSAGE;
     case CiphertextMessage.PREKEY_TYPE:
       return TypeEnum.PREKEY_MESSAGE;
-    case CiphertextMessage.LOKI_FRIEND_REQUEST:
-      return TypeEnum.LOKI_FRIEND_REQUEST;
+    case CiphertextMessage.FALLBACK_MESSAGE:
+      return TypeEnum.FALLBACK_MESSAGE;
     default:
       throw new Error(`_getProtoMessageType: type '${type}' does not exist`);
   }
@@ -481,7 +481,7 @@ SecretSessionCipher.prototype = {
           signalProtocolStore,
           sender
         ).decryptPreKeyWhisperMessage(message.content);
-      case CiphertextMessage.LOKI_FRIEND_REQUEST:
+      case CiphertextMessage.FALLBACK_MESSAGE:
         return new libloki.crypto.FallBackSessionCipher(sender).decrypt(
           message.content
         );
diff --git a/protos/SignalService.proto b/protos/SignalService.proto
index 54391519f..f7b76be2f 100644
--- a/protos/SignalService.proto
+++ b/protos/SignalService.proto
@@ -42,7 +42,7 @@ message Content {
 
 message MediumGroupCiphertext {
   optional bytes ciphertext = 1;
-  optional string source = 2;
+  optional bytes source = 2;
   optional uint32 keyIdx = 3;
 }
 
diff --git a/protos/UnidentifiedDelivery.proto b/protos/UnidentifiedDelivery.proto
index 9b49b8c9b..ee7422d65 100644
--- a/protos/UnidentifiedDelivery.proto
+++ b/protos/UnidentifiedDelivery.proto
@@ -25,7 +25,7 @@ message UnidentifiedSenderMessage {
         enum Type {
             PREKEY_MESSAGE = 1;
             MESSAGE        = 2;
-            LOKI_FRIEND_REQUEST = 3;
+            FALLBACK_MESSAGE = 3;
         }
 
         optional Type              type              = 1;
diff --git a/ts/receiver/contentMessage.ts b/ts/receiver/contentMessage.ts
index 87439cb82..7c125267c 100644
--- a/ts/receiver/contentMessage.ts
+++ b/ts/receiver/contentMessage.ts
@@ -18,6 +18,7 @@ import ByteBuffer from 'bytebuffer';
 import { BlockedNumberController } from '../util/blockedNumberController';
 import { decryptWithSenderKey } from '../session/medium_group/ratchet';
 import { StringUtils } from '../session/utils';
+import { UserUtil } from '../util';
 
 export async function handleContentMessage(envelope: EnvelopePlus) {
   const plaintext = await decrypt(envelope, envelope.content);
@@ -46,8 +47,6 @@ async function decryptForMediumGroup(
     throw new Error(`Secret key is empty for group ${groupId}!`);
   }
 
-  const { senderIdentity } = envelope;
-
   const {
     ciphertext: outerCiphertext,
     ephemeralKey,
@@ -64,15 +63,27 @@ async function decryptForMediumGroup(
     outerCiphertext
   );
 
-  const { ciphertext, keyIdx } = SignalService.MediumGroupCiphertext.decode(
+  const {
+    source,
+    ciphertext,
+    keyIdx,
+  } = SignalService.MediumGroupCiphertext.decode(
     new Uint8Array(mediumGroupCiphertext)
   );
+  const ourNumber = (await UserUtil.getCurrentDevicePubKey()) as string;
+  const sourceAsStr = StringUtils.decode(source, 'hex');
+  if (sourceAsStr === ourNumber) {
+    window.console.info(
+      'Dropping message from ourself after decryptForMediumGroup'
+    );
+    return;
+  }
 
   const plaintext = await decryptWithSenderKey(
     ciphertext,
     keyIdx,
     groupId,
-    senderIdentity
+    sourceAsStr
   );
 
   return plaintext;
diff --git a/ts/session/crypto/MessageEncrypter.ts b/ts/session/crypto/MessageEncrypter.ts
index ba97ca7a2..3380cb205 100644
--- a/ts/session/crypto/MessageEncrypter.ts
+++ b/ts/session/crypto/MessageEncrypter.ts
@@ -4,6 +4,7 @@ import { UserUtil } from '../../util';
 import { CipherTextObject } from '../../../libtextsecure/libsignal-protocol';
 import { encryptWithSenderKey } from '../../session/medium_group/ratchet';
 import { PubKey } from '../types';
+import { StringUtils } from '../utils';
 
 /**
  * Add padding to a message buffer
@@ -90,7 +91,7 @@ export async function encryptForMediumGroup(
   // We should include ciphertext idx in the message
   const content = SignalService.MediumGroupCiphertext.encode({
     ciphertext,
-    source: ourKey,
+    source: new Uint8Array(StringUtils.encode(ourKey, 'hex')),
     keyIdx,
   }).finish();
 
diff --git a/ts/session/messages/outgoing/content/data/mediumgroup/MediumGroupChatMessage.ts b/ts/session/messages/outgoing/content/data/mediumgroup/MediumGroupChatMessage.ts
index 1d5021c16..5cbeb8625 100644
--- a/ts/session/messages/outgoing/content/data/mediumgroup/MediumGroupChatMessage.ts
+++ b/ts/session/messages/outgoing/content/data/mediumgroup/MediumGroupChatMessage.ts
@@ -1,7 +1,6 @@
-import { SignalService } from '../../../../../../protobuf';
 import { ChatMessage } from '../ChatMessage';
 import { PubKey } from '../../../../../types';
-import { MediumGroupMessage } from './MediumGroupMessage';
+import { ClosedGroupChatMessage } from '../group/ClosedGroupChatMessage';
 
 interface MediumGroupChatMessageParams {
   identifier?: string;
@@ -9,21 +8,12 @@ interface MediumGroupChatMessageParams {
   chatMessage: ChatMessage;
 }
 
-export class MediumGroupChatMessage extends MediumGroupMessage {
-  private readonly chatMessage: ChatMessage;
-
+export class MediumGroupChatMessage extends ClosedGroupChatMessage {
   constructor(params: MediumGroupChatMessageParams) {
     super({
-      timestamp: params.chatMessage.timestamp,
       identifier: params.identifier ?? params.chatMessage.identifier,
       groupId: params.groupId,
+      chatMessage: params.chatMessage,
     });
-    this.chatMessage = params.chatMessage;
-  }
-
-  public dataProto(): SignalService.DataMessage {
-    const messageProto = this.chatMessage.dataProto();
-
-    return messageProto;
   }
 }
diff --git a/ts/session/sending/MessageSender.ts b/ts/session/sending/MessageSender.ts
index 1477e25ce..6d28cbcb9 100644
--- a/ts/session/sending/MessageSender.ts
+++ b/ts/session/sending/MessageSender.ts
@@ -39,7 +39,12 @@ export async function send(
     plainTextBuffer,
     encryption
   );
-  const envelope = await buildEnvelope(envelopeType, timestamp, cipherText);
+  const envelope = await buildEnvelope(
+    envelopeType,
+    device.key,
+    timestamp,
+    cipherText
+  );
   const data = wrapEnvelope(envelope);
 
   return pRetry(
@@ -54,11 +59,15 @@ export async function send(
 
 async function buildEnvelope(
   type: SignalService.Envelope.Type,
+  sskSource: string | undefined,
   timestamp: number,
   content: Uint8Array
 ): Promise<SignalService.Envelope> {
   let source: string | undefined;
-  if (type !== SignalService.Envelope.Type.UNIDENTIFIED_SENDER) {
+
+  if (type === SignalService.Envelope.Type.MEDIUM_GROUP_CIPHERTEXT) {
+    source = sskSource;
+  } else if (type !== SignalService.Envelope.Type.UNIDENTIFIED_SENDER) {
     source = await UserUtil.getCurrentDevicePubKey();
   }
 
diff --git a/ts/test/session/unit/crypto/MessageEncrypter_test.ts b/ts/test/session/unit/crypto/MessageEncrypter_test.ts
index eb85516e2..fc130eab7 100644
--- a/ts/test/session/unit/crypto/MessageEncrypter_test.ts
+++ b/ts/test/session/unit/crypto/MessageEncrypter_test.ts
@@ -12,7 +12,7 @@ import * as Ratchet from '../../../../session/medium_group/ratchet';
 // tslint:disable-next-line: max-func-body-length
 describe('MessageEncrypter', () => {
   const sandbox = sinon.createSandbox();
-  const ourNumber = 'ourNumber';
+  const ourNumber = '0123456789abcdef';
 
   beforeEach(() => {
     TestUtils.stubWindow('libsignal', {
diff --git a/ts/test/session/unit/sending/MessageSender_test.ts b/ts/test/session/unit/sending/MessageSender_test.ts
index 1b1411572..66ea30d39 100644
--- a/ts/test/session/unit/sending/MessageSender_test.ts
+++ b/ts/test/session/unit/sending/MessageSender_test.ts
@@ -36,7 +36,7 @@ describe('MessageSender', () => {
   });
 
   describe('send', () => {
-    const ourNumber = 'ourNumber';
+    const ourNumber = '0123456789abcdef';
     let lokiMessageAPISendStub: sinon.SinonStub<
       [string, Uint8Array, number, number],
       Promise<void>