public Point EncodeMessage(Plaintext message)
{
var m = message.ToBigInteger();
//Ensure that message is not too long.
if (m + 1 >= _curve.Prime)
throw new ArgumentException("Message too large to be encrypted. Must be smaller than p (" + _curve.Prime + ").", "message");
return IntegerEncoding(m, _k);
}
public Ciphertext Encrypt(PublicKey Q, Plaintext m)
{
var M = _encoder.EncodeMessage(m);
var k = SelectK();
var c1 = _curve.Generator * k;
var c2 = M + (Q.Point * k);
return new ElGamalCiphertext(c1, c2);
}
static void Main(string[] args)
{
Console.ReadKey();
var str = args[0];
var curve = CurveFactory.secp256k1;
var encoder = new ProbabilisticWeierstrassMessageEncoder(curve, new BigInteger(7));
var encryptor = new ElGamalEncryptor(curve, encoder);
var keys = encryptor.GenerateKeyPair();
var plaintext = new Plaintext(str);
var ciphertext = encryptor.Encrypt(keys.PublicKey, plaintext);
var plaintext2 = encryptor.Decrypt(keys.PrivateKey, ciphertext);
}
public void TestElGamalEncryptDecrypt()
{
var curve = CurveFactory.secp256k1;
var encoder = new ProbabilisticWeierstrassMessageEncoder(curve, new BigInteger(7));
var encryptor = new ElGamalEncryptor(curve, encoder);
var keys = encryptor.GenerateKeyPair();
var m = new Plaintext("Hello, World");
var c = encryptor.Encrypt(keys.PublicKey, m);
var m2 = encryptor.Decrypt(keys.PrivateKey, c);
Assert.AreEqual(m, m2);
}
public void TestEncoderCyclic()
{
var curve = CurveFactory.nistp384;
var encoder = new ProbabilisticWeierstrassMessageEncoder(curve, new BigInteger(7));
//Encode
var m = new Plaintext("A");
BigInteger encoding_key;
var M = encoder.EncodeMessage(m);
//Decode
var m2 = encoder.DecodeMessage(M);
Assert.AreEqual(m, m2);
}
public void TestPlaintextCyclic()
{
var bytes = m.ToByteArray();
var m2 = new Plaintext(bytes);
Assert.AreEqual(m, m2);
}
public void Setup()
{
m = new Plaintext("Hello, World");
}
