private byte[] ComputeEncryptionKey(KexAlgorithm kexAlg, byte[] exchangeHash, int blockSize, byte[] sharedSecret, char letter)
{
var keyBuffer = new byte[blockSize];
var keyBufferIndex = 0;
byte[] currentHash = null;
while (keyBufferIndex < blockSize)
{
using (var worker = new SshDataWorker()) {
worker.WriteMpint(sharedSecret);
worker.Write(exchangeHash);
if (currentHash == null)
{
worker.Write((byte)letter);
worker.Write(this.SessionId);
}
else
{
worker.Write(currentHash);
}
currentHash = kexAlg.ComputeHash(worker.ToByteArray());
}
var currentHashLength = Math.Min(currentHash.Length, blockSize - keyBufferIndex);
Array.Copy(currentHash, 0, keyBuffer, keyBufferIndex, currentHashLength);
keyBufferIndex += currentHashLength;
}
return(keyBuffer);
}
private byte[] ComputeExchangeHash(KexAlgorithm kexAlg, byte[] hostKeyAndCerts, byte[] clientExchangeValue, byte[] serverExchangeValue, byte[] sharedSecret)
{
using (var worker = new SshDataWorker()) {
worker.Write(this.ClientVersion, Encoding.ASCII);
worker.Write(this.ServerVersion, Encoding.ASCII);
worker.WriteBinary(this.exchangeContext.ClientKexInitPayload);
worker.WriteBinary(this.exchangeContext.ServerKexInitPayload);
worker.WriteBinary(hostKeyAndCerts);
worker.WriteMpint(clientExchangeValue);
worker.WriteMpint(serverExchangeValue);
worker.WriteMpint(sharedSecret);
return(kexAlg.ComputeHash(worker.ToByteArray()));
}
}
