public bool Verify(byte[] signature, byte[] data, uint160 nonce)
{
byte[] output = new byte[256];
var msg = Utils.Combine(nonce.ToBytes(), data);
Sha512Digest sha512 = new Sha512Digest();
var generator = new Mgf1BytesGenerator(sha512);
generator.Init(new MgfParameters(msg));
generator.GenerateBytes(output, 0, output.Length);
var input = new BigInteger(1, output);
if (input.CompareTo(_Key.Modulus) >= 0)
{
return(false);
}
if (signature.Length > 256)
{
return(false);
}
var signatureInt = new BigInteger(1, signature);
if (signatureInt.CompareTo(_Key.Modulus) >= 0)
{
return(false);
}
var engine = new RsaBlindedEngine();
engine.Init(false, _Key);
return(input.Equals(engine.ProcessBlock(signatureInt)));
}
/// <summary>
/// MGF1 Mask Generation Function based on the SHA-256 hash function
/// </summary>
/// <param name="data">Input to process</param>
/// <param name="keySize">The size of the RSA key in bits</param>
/// <returns>Hashed result as a 256 Bytes array (2048 Bits)</returns>
internal static byte[] MGF1_SHA256(byte[] data, int keySize)
{
byte[] output = new byte[GetByteLength(keySize)];
Sha256Digest sha256 = new Sha256Digest();
var generator = new Mgf1BytesGenerator(sha256);
generator.Init(new MgfParameters(data));
generator.GenerateBytes(output, 0, output.Length);
return(output);
}
public override BigInteger CalculateSessionKey()
{
if (S == null)
{
throw new CryptoException("Impossible to compute Key: some data are missing from the previous operations (S)");
}
byte[] output = new byte[40];
Mgf1BytesGenerator generator = new Mgf1BytesGenerator(digest);
generator.Init(new MgfParameters(S.ToByteArrayUnsigned()));
generator.GenerateBytes(output, 0, output.Length);
Key = new BigInteger(1, output);
return(Key);
}
public byte[] XOR(byte[] data)
{
byte[] keyBytes = ToBytes();
Sha512Digest sha512 = new Sha512Digest();
var generator = new Mgf1BytesGenerator(sha512);
generator.Init(new MgfParameters(keyBytes));
var keyHash = new byte[data.Length];
generator.GenerateBytes(keyHash, 0, keyHash.Length);
var encrypted = new byte[data.Length];
for (int i = 0; i < encrypted.Length; i++)
{
encrypted[i] = (byte)(data[i] ^ keyHash[i]);
}
return(encrypted);
}
public byte[] Sign(byte[] data, out uint160 nonce)
{
while (true)
{
byte[] output = new byte[256];
nonce = new uint160(RandomUtils.GetBytes(20));
Sha512Digest sha512 = new Sha512Digest();
var msg = Utils.Combine(nonce.ToBytes(), data);
var generator = new Mgf1BytesGenerator(sha512);
generator.Init(new MgfParameters(msg));
generator.GenerateBytes(output, 0, output.Length);
var input = new BigInteger(1, output);
if (input.CompareTo(_Key.Modulus) >= 0)
{
continue;
}
var engine = new RsaCoreEngine();
engine.Init(true, _Key);
return(engine.ConvertOutput(engine.ProcessBlock(input)));
}
}
