Don't remote-encrypt key exchange messages

src/org/thoughtcrime/securesms/transport/SmsTransport.java

@@ -40,11 +40,14 @@ public class SmsTransport {
   }
 
   private void deliverSecureMessage(SmsMessageRecord message) throws UndeliverableMessageException {
+    MultipartSmsMessageHandler multipartMessageHandler = new MultipartSmsMessageHandler();
+    OutgoingTextMessage transportMessage               = OutgoingTextMessage.from(message);
+
+    if (message.isSecure()) {
       String encryptedMessage = getAsymmetricEncrypt(masterSecret, message.getBody().getBody(),
                                                      message.getIndividualRecipient());
-
+      transportMessage = transportMessage.withBody(encryptedMessage);
-    OutgoingTextMessage transportMessage = OutgoingTextMessage.from(message).withBody(encryptedMessage);
+    }
-    MultipartSmsMessageHandler multipartMessageHandler = new MultipartSmsMessageHandler();
 
     ArrayList<String> messages                = multipartMessageHandler.divideMessage(transportMessage);
     ArrayList<PendingIntent> sentIntents      = constructSentIntents(message.getId(), message.getType(), messages);