public void GGHTest()
{
//Private key, public key and error vector taken from the book:
//Hoffstein, J.; Pipher, J. & Silverman, J. H.
//Axler, S. & Ribet, K. A. (Eds.)
//'An Introduction to Mathematical Cryptography'
//Springer, 2008
//Chapter 'The GGH public key cryptosystem'
//Pages 384ff
VectorND[] privateVectors =
{
new VectorND(new BigInteger[] { -97, 19, 19 }),
new VectorND(new BigInteger[] { -36, 30, 86 }),
new VectorND(new BigInteger[] { -184, -64, 78 })
};
LatticeND privateKey = new LatticeND(privateVectors, false);
VectorND[] publicVectors =
{
new VectorND(new BigInteger[] { -4179163, -1882253, 583183 }),
new VectorND(new BigInteger[] { -3184353, -1434201, 444361 }),
new VectorND(new BigInteger[] { -5277320, -2376852, 736426 })
};
LatticeND publicKey = new LatticeND(publicVectors, false);
VectorND errorVector = new VectorND(new BigInteger[] { -4, -3, -2 });
GGHModel ggh = new GGHModel(3, privateKey.ToMatrixND(), publicKey.ToMatrixND(), errorVector);
for (int i = 0; i < 1000; i++)
{
string message = GenerateMessage(1, 100);
VectorND cipher = ggh.Encrypt(message);
string decryptedMessage = ggh.Decrypt(cipher);
Assert.AreEqual(message, decryptedMessage);
}
}
public void LWETest()
{
//Test for single bit encryption
//Example taken from my own master thesis (sadly in the absence of an alternative example)
VectorND[] SVectors =
{
new VectorND(new BigInteger[] { 7, 7 })
};
LatticeND S = new LatticeND(SVectors, false);
VectorND[] AVectors =
{
new VectorND(new BigInteger[] { 4, 3, 4, 0, 5 }),
new VectorND(new BigInteger[] { 3, 3, 0, 7, 1 })
};
LatticeND A = new LatticeND(AVectors, false);
VectorND[] eVectors =
{
new VectorND(new BigInteger[] { 7, 2, 4, 5, 2 })
};
LatticeND e = new LatticeND(eVectors, false);
const int q = 9;
LWEModel lwe = new LWEModel(S.ToMatrixND(), A.ToMatrixND(), e.ToMatrixND(), q, 1);
VectorND[] rVectors =
{
new VectorND(new BigInteger[] { 1, 1, 0, 0, 0 })
};
LatticeND r = new LatticeND(rVectors, false);
r.Transpose();
lwe.SetRandomVector(r.ToMatrixND());
//Cryptosystem correct?
VectorND[] BVectors =
{
new VectorND(new BigInteger[] { 2, 8, 5, 0, 8 })
};
LatticeND B = new LatticeND(BVectors, false);
Assert.AreEqual(B.ToMatrixND().ToString(), lwe.B.ToString());
//Encryption and decryption correct?
//Message = 0
MatrixND messageMatrix = new MatrixND(1, 1);
messageMatrix[0, 0] = 0;
MatrixND cipher = lwe.Encrypt(messageMatrix);
MatrixND expectedCipherMatrix = new MatrixND(1, 1);
expectedCipherMatrix[0, 0] = 1;
Assert.AreEqual(cipher.ToString(), expectedCipherMatrix.ToString());
MatrixND decryptedMessage = lwe.Decrypt(cipher);
Assert.AreEqual(messageMatrix.ToString(), decryptedMessage.ToString());
//Message = 1
messageMatrix[0, 0] = 1;
cipher = lwe.Encrypt(messageMatrix);
expectedCipherMatrix[0, 0] = 5;
Assert.AreEqual(cipher.ToString(), expectedCipherMatrix.ToString());
decryptedMessage = lwe.Decrypt(cipher);
Assert.AreEqual(messageMatrix.ToString(), decryptedMessage.ToString());
}