Register extra keying material at registration.

Signal/src/environment/SignalKeyingStorage.h

@@ -45,6 +45,14 @@
 
 +(NSData*)signalingMacKey;
 +(NSData*)signalingCipherKey;
+
+/**
+ *  Returns the extra keying material generated at registration. 
+ ⚠️ Warning: Users of older versions of Signal (<= 2.1.1) might have the signaling cipher key as extra keing material.
+ *
+ *  @return Extra keying material from registration time
+ */
+
 +(NSData*)signalingExtraKey;
 
 @end

Signal/src/network/http/RPAPICall.m

@@ -58,7 +58,7 @@
     
     NSData* signalingCipherKey    = SignalKeyingStorage.signalingCipherKey;
     NSData* signalingMacKey       = SignalKeyingStorage.signalingMacKey;
-    NSData* signalingExtraKeyData = SignalKeyingStorage.signalingCipherKey;
+    NSData* signalingExtraKeyData = SignalKeyingStorage.signalingExtraKey;
     NSString* encodedSignalingKey = @[signalingCipherKey, signalingMacKey, signalingExtraKeyData].ows_concatDatas.encodedAsBase64;
     apiCall.parameters            = @{@"key" : encodedSignalingKey, @"challenge" : verificationCode};
 

Signal/src/phone/signaling/SignalUtil.m

@@ -98,7 +98,7 @@
     
     NSData* signalingCipherKey = SignalKeyingStorage.signalingCipherKey;
     NSData* signalingMacKey = SignalKeyingStorage.signalingMacKey;
-    NSData* signalingExtraKeyData = SignalKeyingStorage.signalingCipherKey;
+    NSData* signalingExtraKeyData = SignalKeyingStorage.signalingExtraKey;
     
     NSString* encodedSignalingKey = @[signalingCipherKey, signalingMacKey, signalingExtraKeyData].ows_concatDatas.encodedAsBase64;
     NSString* body = @{@"key" : encodedSignalingKey, @"challenge" : challenge}.encodedAsJson;