void Send(Stream underlying, byte[] buf, int pos, int cnt)
{
// Trace.WriteLine("ENC >> " + Utils.Utf8.GetString(buf, pos, Math.Max(cnt, 40)));
var total = Math.Min(cnt, _encryptBuffer.Length - (_icSent ? 0 : _nonceLen));
_chachaEncrypt.Crypt(buf, pos, _encryptBuffer, _icSent ? 0 : _nonceLen, total);
var size = total;
if (!_icSent)
{
_chachaEncrypt.Nonce.CopyTo(_encryptBuffer, 0); // crypt been done with a shift to left this space for nonce
size += _nonceLen;
_icSent = true;
}
underlying.Write(_encryptBuffer, 0, size);
// write the rest in case if _encryptBuffer is smaller than buf + nonce
if (total < cnt)
{
Send(underlying, buf, pos + total, cnt - total);
}
}
int Read(Stream underlying, byte[] buf, int pos, int cnt)
{
var r = underlying.Read(_readBuffer, 0, Math.Min(cnt, _readBuffer.Length));
if (r == 0)
{
return(0);
}
var ro = 0;
if (!_icReceived)
{
var remoteNonce = new byte[_nonceLen];
Array.Copy(_readBuffer, 0, remoteNonce, 0, _nonceLen);
_icReceived = true;
r -= _nonceLen;
ro += _nonceLen;
_chachaDecrypt = new ChaCha20(_key, remoteNonce);
}
_chachaDecrypt.Crypt(_readBuffer, ro, buf, pos, r);
// Trace.WriteLine("DEC << " + Utils.Utf8.GetString(buf, pos, Math.Max(r, 40)));
return(r);
}