/// <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));
}
