private static byte[] GenerateAEADNonce(byte[] nonceImplicit, byte[] nonceExplicit)
{
byte[] nonce = new byte[nonceImplicit.Length + nonceExplicit.Length];
Buffer.BlockCopy(nonceImplicit, 0, nonce, 0, nonceImplicit.Length);
Buffer.BlockCopy(nonceExplicit, 0, nonce, nonceImplicit.Length, nonceExplicit.Length);
return nonce;
}