public static void InitializeSession(SessionState sessionState,
SymmetricSignalProtocolParameters parameters)
{
if (IsAlice(parameters.GetOurBaseKey().GetPublicKey(), parameters.GetTheirBaseKey()))
{
AliceSignalProtocolParameters.Builder aliceParameters = AliceSignalProtocolParameters.NewBuilder();
aliceParameters.SetOurBaseKey(parameters.GetOurBaseKey())
.SetOurIdentityKey(parameters.GetOurIdentityKey())
.SetTheirRatchetKey(parameters.GetTheirRatchetKey())
.SetTheirIdentityKey(parameters.GetTheirIdentityKey())
.SetTheirSignedPreKey(parameters.GetTheirBaseKey())
.SetTheirOneTimePreKey(May <IEcPublicKey> .NoValue);
InitializeSession(sessionState, aliceParameters.Create());
}
else
{
BobSignalProtocolParameters.Builder bobParameters = BobSignalProtocolParameters.NewBuilder();
bobParameters.SetOurIdentityKey(parameters.GetOurIdentityKey())
.SetOurRatchetKey(parameters.GetOurRatchetKey())
.SetOurSignedPreKey(parameters.GetOurBaseKey())
.SetOurOneTimePreKey(May <EcKeyPair> .NoValue)
.SetTheirBaseKey(parameters.GetTheirBaseKey())
.SetTheirIdentityKey(parameters.GetTheirIdentityKey());
InitializeSession(sessionState, bobParameters.Create());
}
}
public static void InitializeSession(SessionState sessionState, AliceSignalProtocolParameters parameters)
{
try
{
sessionState.SetSessionVersion(CiphertextMessage.CurrentVersion);
sessionState.SetRemoteIdentityKey(parameters.GetTheirIdentityKey());
sessionState.SetLocalIdentityKey(parameters.GetOurIdentityKey().GetPublicKey());
EcKeyPair sendingRatchetKey = Curve.GenerateKeyPair();
MemoryStream secrets = new MemoryStream();
byte[] discontinuityBytes = GetDiscontinuityBytes();
secrets.Write(discontinuityBytes, 0, discontinuityBytes.Length);
byte[] agree1 = Curve.CalculateAgreement(parameters.GetTheirSignedPreKey(),
parameters.GetOurIdentityKey().GetPrivateKey());
byte[] agree2 = Curve.CalculateAgreement(parameters.GetTheirIdentityKey().GetPublicKey(),
parameters.GetOurBaseKey().GetPrivateKey());
byte[] agree3 = Curve.CalculateAgreement(parameters.GetTheirSignedPreKey(),
parameters.GetOurBaseKey().GetPrivateKey());
secrets.Write(agree1, 0, agree1.Length);
secrets.Write(agree2, 0, agree2.Length);
secrets.Write(agree3, 0, agree3.Length);
if (parameters.GetTheirOneTimePreKey().HasValue)
{
byte[] otAgree = Curve.CalculateAgreement(parameters.GetTheirOneTimePreKey().ForceGetValue(),
parameters.GetOurBaseKey().GetPrivateKey());
secrets.Write(otAgree, 0, otAgree.Length);
}
DerivedKeys derivedKeys = CalculateDerivedKeys(secrets.ToArray());
Pair <RootKey, ChainKey> sendingChain = derivedKeys.GetRootKey().CreateChain(parameters.GetTheirRatchetKey(), sendingRatchetKey);
sessionState.AddReceiverChain(parameters.GetTheirRatchetKey(), derivedKeys.GetChainKey());
sessionState.SetSenderChain(sendingRatchetKey, sendingChain.Second());
sessionState.SetRootKey(sendingChain.First());
}
catch (IOException e)
{
throw new Exception(e.Message);
}
}