///// <summary>
///// Create new Ed25519 signature
///// </summary>
///// <param name="signature">Buffer for signature</param>
///// <param name="message">Message bytes</param>
///// <param name="expandedPrivateKey">Expanded form of private key</param>
//public static void Sign(ArraySegment<byte> signature, ArraySegment<byte> message, ArraySegment<byte> expandedPrivateKey) {
// Contract.Requires<ArgumentNullException>(signature.Array != null && message.Array != null && expandedPrivateKey.Array != null);
// Contract.Requires<ArgumentException>(expandedPrivateKey.Count == ExpandedPrivateKeySize);
// Ed25519Operations.crypto_sign(signature.Array, signature.Offset, message.Array, message.Offset, message.Count, expandedPrivateKey.Array, expandedPrivateKey.Offset);
//}
///// <summary>
///// Create new Ed25519 signature
///// </summary>
///// <param name="signature">Buffer for signature</param>
///// <param name="message">Message bytes</param>
///// <param name="expandedPrivateKey">Expanded form of private key</param>
//public static byte[] Sign(byte[] message, byte[] expandedPrivateKey) {
// Contract.Requires<ArgumentNullException>(message != null && expandedPrivateKey != null);
// Contract.Requires<ArgumentException>(expandedPrivateKey.Length == ExpandedPrivateKeySize);
// var signature = new byte[SignatureSize];
// Sign(new ArraySegment<byte>(signature), new ArraySegment<byte>(message), new ArraySegment<byte>(expandedPrivateKey));
// return signature;
//}
public static byte[] SignWithPrehashed(byte[] message, byte[] privateKey, byte[] publicKey)
{
Contract.Requires <ArgumentNullException>(message != null && privateKey != null && publicKey != null);
Contract.Requires <ArgumentException>(privateKey.Length == ExpandedPrivateKeySize);
Contract.Requires <ArgumentException>(publicKey.Length == PublicKeySize);
var signature = new byte[SignatureSize];
Ed25519Operations.crypto_sign_prehashed(signature, message, message.Length, privateKey, publicKey);
return(signature);
}