/// <summary>
/// When overridden in a derived class, writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.
/// </summary>
/// <param name="buffer">An array of bytes. This method copies <paramref name="count"/> bytes from <paramref name="buffer"/> to the current stream.</param>
/// <param name="offset">The zero-based byte offset in <paramref name="buffer"/> at which to begin copying bytes to the current stream.</param>
/// <param name="count">The number of bytes to be written to the current stream.</param>
/// <exception cref="T:System.ArgumentException">The sum of <paramref name="offset"/> and <paramref name="count"/> is greater than the buffer length. </exception>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="buffer"/> is null. </exception>
/// <exception cref="T:System.ArgumentOutOfRangeException">
/// <paramref name="offset"/> or <paramref name="count"/> is negative. </exception>
/// <exception cref="T:System.IO.IOException">An I/O error occurs. </exception>
/// <exception cref="T:System.NotSupportedException">The stream does not support writing. </exception>
/// <exception cref="T:System.ObjectDisposedException">Methods were called after the stream was closed. </exception>
public override void Write(byte[] buffer, int offset, int count)
{
if (!_init)
{
if (_encrypt)
{
_output.Write(_nonce, 0, _nonce.Length);
}
else
{
Array.Copy(buffer, 0, _nonce, 0, _nonce.Length);
offset = offset + _nonce.Length;
count = count - _nonce.Length;
}
_initFunc(_nonce, _cipher, _header, _encrypt);
_init = true;
}
var outBuffer = new byte[_cipher.GetUpdateOutputSize(count)];
var outLen = _cipher.ProcessBytes(buffer, offset, count, outBuffer, 0);
_output.Write(outBuffer, 0, outLen);
Secure.Clear(outBuffer);
_outLen += outLen;
_inLen += count;
}
/// <summary>
/// Releases the unmanaged resources used by the <see cref="T:System.IO.Stream"/> and optionally releases the managed resources.
/// </summary>
/// <param name="disposing">true to release both managed and unmanaged resources; false to release only unmanaged resources.</param>
protected override void Dispose(bool disposing)
{
Flush();
Secure.Clear(_nonce);
_nonce = null;
Secure.Clear(_header);
_header = null;
//_cipher.Reset();
_cipher = null;
_initFunc = null;
_output = null;
_outLen = 0;
_init = false;
_inLen = 0;
base.Dispose(disposing);
}
/// <summary>
/// Finishes this instance.
/// </summary>
/// <exception cref="InvalidCryptoDataException"></exception>
public override void Finish()
{
try
{
if (!_init && _encrypt)
{
_output.Write(_nonce, 0, _nonce.Length);
_initFunc(_nonce, _cipher, _header, _encrypt);
_init = true;
}
var buffLen = _cipher.GetOutputSize(_inLen) - _outLen;
var buffer = new byte[buffLen];
var writeLen = _cipher.DoFinal(buffer, 0);
_output.Write(buffer, 0, writeLen);
Secure.Clear(buffer);
}
catch (InvalidCipherTextException ex)
{
throw new InvalidCryptoDataException(ex.Message);
}
}