/// <summary>
/// Open decrypts the next ciphertext in the STREAM, authenticates the
/// decrypted plaintext and the associated data and, if successful, returns
/// the result. In case of failed decryption, this method throws
/// <see cref="CryptographicException">.
/// </summary>
/// <param name="ciphertext">The ciphertext to decrypt.</param>
/// <param name="data">Associated data items to authenticate.</param>
/// <param name="last">True if this is the last block in the STREAM.</param>
/// <returns>The decrypted plaintext.</returns>
/// <exception cref="CryptographicException">Thrown when the ciphertext is invalid.</exception>
public byte[] Open(byte[] ciphertext, byte[] data = null, bool last = false)
{
if (disposed)
{
throw new ObjectDisposedException(nameof(StreamEncryptor));
}
if (finished)
{
throw new CryptographicException("STREAM is already finished.");
}
finished = last;
return(siv.Open(ciphertext, data, nonce.Next(last)));
}
/// <summary>
/// Open decrypts ciphertext, authenticates the decrypted plaintext
/// and the associated data and, if successful, returns the result.
/// In case of failed decryption, this method throws
/// <see cref="CryptographicException">.
/// </summary>
/// <param name="ciphertext">The ciphertext to decrypt.</param>
/// <param name="nonce">The nonce for encryption.</param>
/// <param name="data">Associated data to authenticate.</param>
/// <returns>The decrypted plaintext.</returns>
/// <exception cref="CryptographicException">Thrown when the ciphertext is invalid.</exception>
public byte[] Open(byte[] ciphertext, byte[] nonce = null, byte[] data = null)
{
return(siv.Open(ciphertext, data, nonce));
}