public Maybe<UInt32> Process(SessionRecord sessionRecord, PreKeyWhisperMessage message)
{
var messageVersion = message.MessageVersion;
var theirIdentityKey = message.IdentityKey;
Maybe<UInt32> unsignedPreKeyId;
if (!_identityKeyStore.IsTrustedIdentity(_remoteAddress.Name, theirIdentityKey)) {
throw new UntrustedIdentityException();
}
switch (messageVersion)
{
case 2:
unsignedPreKeyId = ProcessV2(sessionRecord, message);
break;
case 3:
unsignedPreKeyId = ProcessV3(sessionRecord, message);
break;
default:
throw new InvalidOperationException("Unknown version: " + messageVersion);
}
_identityKeyStore.SaveIdentity(_remoteAddress.Name, theirIdentityKey);
return unsignedPreKeyId;
}
public void TestBasicSessionV3()
{
var aliceSessionRecord = new SessionRecord();
var bobSessionRecord = new SessionRecord();
InitializeSessionsV3(aliceSessionRecord.SessionState, bobSessionRecord.SessionState);
RunInteraction(aliceSessionRecord, bobSessionRecord);
}
public void StoreSession(AxolotlAddress address, SessionRecord record)
{
_sessions.Add(address, record.Serialize());
}
private void RunInteraction(SessionRecord aliceSessionRecord, SessionRecord bobSessionRecord)
{
var aliceStore = new TestInMemoryAxolotlStore();
var bobStore = new TestInMemoryAxolotlStore();
aliceStore.StoreSession(new AxolotlAddress("+14159999999", 1), aliceSessionRecord);
bobStore.StoreSession(new AxolotlAddress("+14158888888", 1), bobSessionRecord);
var aliceCipher = new SessionCipher(aliceStore, new AxolotlAddress("+14159999999", 1));
var bobCipher = new SessionCipher(bobStore, new AxolotlAddress("+14158888888", 1));
var alicePlaintext = Encoding.UTF8.GetBytes ("This is a plaintext message.");
var message = aliceCipher.Encrypt(alicePlaintext);
var bobPlaintext = bobCipher.Decrypt(new WhisperMessage(message.Serialize()));
Assert.True(ArrayComparer.Compare(alicePlaintext, bobPlaintext));
var bobReply = Encoding.UTF8.GetBytes ("This is a message from Bob.");
var reply = bobCipher.Encrypt(bobReply);
var receivedReply = aliceCipher.Decrypt(new WhisperMessage(reply.Serialize()));
Assert.True(ArrayComparer.Compare(bobReply, receivedReply));
var aliceCiphertextMessages = new List<CiphertextMessage>();
var alicePlaintextMessages = new List<byte[]>();
for (int i = 0; i < 50; i++) {
alicePlaintextMessages.Add (Encoding.UTF8.GetBytes (string.Format ("смерть за смерть {0}", i)));
aliceCiphertextMessages.Add(aliceCipher.Encrypt(Encoding.UTF8.GetBytes (string.Format ("смерть за смерть {0}", i))));
}
long seed = CurrentMillis;
aliceCiphertextMessages.Sort ((x, y) => new Random((int)CurrentMillis + DateTime.UtcNow.Day).Next (-1, 2));
alicePlaintextMessages.Sort ((x, y) => new Random ((int)CurrentMillis + DateTime.UtcNow.Minute).Next (-1, 2));
for (int i = 0; i < aliceCiphertextMessages.Count / 2; i++) {
byte[] receivedPlaintext = bobCipher.Decrypt(new WhisperMessage(aliceCiphertextMessages[i].Serialize()));
Assert.True(ArrayComparer.Compare(receivedPlaintext, alicePlaintextMessages[i]));
}
var bobCiphertextMessages = new List<CiphertextMessage>();
var bobPlaintextMessages = new List<byte[]>();
for (int i=0;i<20;i++) {
bobPlaintextMessages.Add(Encoding.UTF8.GetBytes (string.Format ("смерть за смерть {0}", i)));
bobCiphertextMessages.Add(bobCipher.Encrypt(Encoding.UTF8.GetBytes (string.Format ("смерть за смерть {0}", i))));
}
seed = CurrentMillis;
bobCiphertextMessages.Sort ((x, y) => new Random((int)CurrentMillis + DateTime.UtcNow.Day).Next (-1, 2));
bobPlaintextMessages.Sort ((x, y) => new Random ((int)CurrentMillis + DateTime.UtcNow.Minute).Next (-1, 2));
for (int i = 0; i < bobCiphertextMessages.Count / 2; i++) {
byte[] receivedPlaintext = aliceCipher.Decrypt(new WhisperMessage(bobCiphertextMessages[i].Serialize()));
Assert.True(ArrayComparer.Compare(receivedPlaintext, bobPlaintextMessages[i]));
}
for (int i = aliceCiphertextMessages.Count / 2; i < aliceCiphertextMessages.Count; i++) {
byte[] receivedPlaintext = bobCipher.Decrypt(new WhisperMessage(aliceCiphertextMessages[i].Serialize()));
Assert.True(ArrayComparer.Compare(receivedPlaintext, alicePlaintextMessages[i]));
}
for (int i=bobCiphertextMessages.Count / 2; i < bobCiphertextMessages.Count; i++) {
byte[] receivedPlaintext = aliceCipher.Decrypt(new WhisperMessage(bobCiphertextMessages[i].Serialize()));
Assert.True(ArrayComparer.Compare(receivedPlaintext, bobPlaintextMessages[i]));
}
}
private Maybe<UInt32> ProcessV3(SessionRecord sessionRecord, PreKeyWhisperMessage message)
{
if (sessionRecord.HasSessionState(message.MessageVersion, message.BaseKey.Serialize()))
{
Logger.w("SessionBuilder : ", "We've already setup a session for this V3 message, letting bundled message fall through...");
return Maybe<UInt32>.Nothing;
}
var ourSignedPreKey = _signedPreKeyStore.LoadSignedPreKey(message.SignedPreKeyId).keyPair;
var bobParams = BobAxolotlParameters.NewBuilder ();
bobParams.SetTheirBaseKey(message.BaseKey)
.SetTheirIdentityKey(message.IdentityKey)
.SetOurIdentityKey(_identityKeyStore.GetIdentityKeyPair())
.SetOurSignedPreKey(ourSignedPreKey)
.SetOurRatchetKey(ourSignedPreKey);
if (message.PreKeyId.IsSomething()) {
message.PreKeyId.Do (pKid => {
bobParams.SetOurOneTimePreKey(_preKeyStore.LoadPreKey(pKid).KeyPair.ToMaybe());
});
} else {
bobParams.SetOurOneTimePreKey(Maybe<ECKeyPair>.Nothing);
}
if (!sessionRecord.IsFresh) sessionRecord.ArchiveCurrentState();
RatchetingSession.InitializeSession(sessionRecord.SessionState, message.MessageVersion, bobParams.Create());
sessionRecord.SessionState.LocalRegistrationId = _identityKeyStore.GetLocalRegistrationId();
sessionRecord.SessionState.RemoteRegistrationId = message.RegistrationId;
sessionRecord.SessionState.AliceBaseKey = message.BaseKey.Serialize();
if (message.PreKeyId.IsSomething() &&
message.PreKeyId.Value != Medium.MAX_VALUE) {
return message.PreKeyId;
} else {
return Maybe<UInt32>.Nothing;
}
}
private Maybe<UInt32> ProcessV2(SessionRecord sessionRecord, PreKeyWhisperMessage message)
{
if (message.PreKeyId.IsNothing()) {
throw new InvalidKeyIdException("V2 message requires one time prekey id!");
}
if (!_preKeyStore.ContainsPreKey(message.PreKeyId.Value) &&
_sessionStore.ContainsSession(_remoteAddress))
{
Console.WriteLine("TAG" + "We've already processed the prekey part of this V2 session, letting bundled message fall through...");
return Maybe<UInt32>.Nothing;
}
var ourPreKey = _preKeyStore.LoadPreKey(message.PreKeyId.Value).KeyPair;
var bobParams = BobAxolotlParameters.NewBuilder();
bobParams.SetOurIdentityKey(_identityKeyStore.GetIdentityKeyPair())
.SetOurSignedPreKey(ourPreKey)
.SetOurRatchetKey(ourPreKey)
.SetOurOneTimePreKey(Maybe<ECKeyPair>.Nothing)
.SetTheirIdentityKey(message.IdentityKey)
.SetTheirBaseKey(message.BaseKey);
if (!sessionRecord.IsFresh) sessionRecord.ArchiveCurrentState();
RatchetingSession.InitializeSession(sessionRecord.SessionState, message.MessageVersion, bobParams.Create());
sessionRecord.SessionState.LocalRegistrationId = _identityKeyStore.GetLocalRegistrationId();
sessionRecord.SessionState.RemoteRegistrationId = message.RegistrationId;
sessionRecord.SessionState.AliceBaseKey = message.BaseKey.Serialize();
if (message.PreKeyId.Value != Medium.MAX_VALUE) {
return message.PreKeyId;
} else {
return Maybe<UInt32>.Nothing;
}
}
public void StoreSession(AxolotlAddress address, SessionRecord record)
{
_sessionStore.StoreSession(address, record);
}
private byte[] Decrypt(SessionRecord sessionRecord, WhisperMessage ciphertext)
{
lock(SESSION_LOCK)
{
var previousStates = new List<SessionState>(sessionRecord.PreviousStates);
var exceptions = new List<Exception>();
try
{
var sessionState = new SessionState(sessionRecord.SessionState);
byte[] plaintext = Decrypt(sessionState, ciphertext);
sessionRecord.SetState(sessionState);
return plaintext;
}
catch(InvalidMessageException e)
{
exceptions.Add(e);
}
// TODO: Check~
foreach(var state in previousStates)
{
try
{
var promotedState = new SessionState(state);
byte[] plainText = Decrypt(promotedState, ciphertext);
sessionRecord.PreviousStates.Remove(state);
return plainText;
}
catch(InvalidMessageException e)
{
exceptions.Add(e);
}
}
throw new InvalidMessageException("No valid sessions.", exceptions);
}
}