public static byte[] SecretKeyFromSeed(byte[] privateKeySeed)
{
if (privateKeySeed == null)
{
throw new ArgumentNullException("privateKeySeed");
}
if (privateKeySeed.Length != PrivateKeySeedSizeInBytes)
{
throw new ArgumentException("privateKeySeed");
}
byte[] sk = new byte[PrivateKeySeedSizeInBytes];
Ed25519Operations.crypto_secret_key_from_seed(sk, 0, privateKeySeed, 0);
return(sk);
}