/// <summary>
/// Prepares a <see cref="Poly1305"/> instance using <see cref="ChaCha20"/>
/// and Counter=0 to generate the corresponding key.
/// </summary>
/// <param name="Key">Key</param>
/// <param name="Nonce">Nonce</param>
/// <returns>Authenticator</returns>
public static Poly1305 FromChaCha20(byte[] Key, byte[] Nonce)
{
ChaCha20 Cipher = new ChaCha20(Key, 0, Nonce);
byte[] Key2 = Cipher.GetBytes(32);
return(new Poly1305(Key2));
}
/// <summary>
/// Class implementing the authenticated encryption with additional
/// data algorithm AEAD_CHACHA20_POLY1305.
/// </summary>
/// <param name="Key">Key</param>
/// <param name="Nonce">Nonce value</param>
public AeadChaCha20Poly1305(byte[] Key, byte[] Nonce)
{
this.chaCha20 = new ChaCha20(Key, 0, Nonce);
this.poly1305 = new Poly1305(this.chaCha20.GetBytes(32));
this.chaCha20.NextBlock();
}