private static DerivedKeys CalculateDerivedKeys(uint sessionVersion, byte[] masterSecret)
{
HKDF kdf = HKDF.CreateFor(sessionVersion);
byte[] derivedSecretBytes = kdf.DeriveSecrets(masterSecret, Encoding.UTF8.GetBytes("WhisperText"), 64);
byte[][] derivedSecrets = ByteUtil.Split(derivedSecretBytes, 32, 32);
return(new DerivedKeys(new RootKey(kdf, derivedSecrets[0]),
new ChainKey(kdf, derivedSecrets[1], 0)));
}
public ChainKey GetReceiverChainKey(ECPublicKey senderEphemeral)
{
Pair <Chain, uint> receiverChainAndIndex = GetReceiverChain(senderEphemeral);
Chain receiverChain = receiverChainAndIndex.First();
if (receiverChain == null)
{
return(null);
}
else
{
return(new ChainKey(HKDF.CreateFor(GetSessionVersion()),
receiverChain.ChainKey.Key.ToByteArray(),
receiverChain.ChainKey.Index));
}
}
public ChainKey GetSenderChainKey()
{
Chain.Types.ChainKey chainKeyStructure = sessionStructure.SenderChain.ChainKey;
return(new ChainKey(HKDF.CreateFor(GetSessionVersion()),
chainKeyStructure.Key.ToByteArray(), chainKeyStructure.Index));
}
public RootKey GetRootKey()
{
return(new RootKey(HKDF.CreateFor(GetSessionVersion()),
this.sessionStructure.RootKey.ToByteArray()));
}