/// <summary>
/// Deterministically generates a blinding polynomial from a seed and a message representative
/// </summary>
///
/// <param name="Seed">The seed value</param>
///
/// <returns>A blinding polynomial</returns>
private IPolynomial GenerateBlindingPoly(byte[] Seed)
{
int N = _encParams.N;
IndexGenerator ig = new IndexGenerator(Seed, _encParams);
if (_encParams.PolyType == TernaryPolynomialType.PRODUCT) //.8, .6
{
SparseTernaryPolynomial r1 = SparseTernaryPolynomial.GenerateBlindingPoly(ig, N, _encParams.DR1);
SparseTernaryPolynomial r2 = SparseTernaryPolynomial.GenerateBlindingPoly(ig, N, _encParams.DR2);
SparseTernaryPolynomial r3 = SparseTernaryPolynomial.GenerateBlindingPoly(ig, N, _encParams.DR3);
return(new ProductFormPolynomial(r1, r2, r3));
}
else
{
if (_encParams.Sparse)
{
return(SparseTernaryPolynomial.GenerateBlindingPoly(ig, N, _encParams.DR));
}
else
{
return(DenseTernaryPolynomial.GenerateBlindingPoly(ig, N, _encParams.DR));
}
}
}
/// <summary>
/// Read a Private key from a stream
/// </summary>
///
/// <param name="KeyStream">The stream containing the key</param>
///
/// <returns>An initialized NTRUPrivateKey class</returns>
///
/// <exception cref="NTRUException">Thrown if the stream can not be read</exception>
public static NTRUPrivateKey From(MemoryStream KeyStream)
{
BinaryReader dataStream = new BinaryReader(KeyStream);
try
{
// ins.Position = 0; wrong here, ins pos is wrong
int n = IntUtils.ReadShort(KeyStream);
int q = IntUtils.ReadShort(KeyStream);
byte flags = dataStream.ReadByte();
bool sparse = (flags & 1) != 0;
bool fastFp = (flags & 2) != 0;
IPolynomial t;
TernaryPolynomialType polyType = (flags & 4) == 0 ?
TernaryPolynomialType.SIMPLE :
TernaryPolynomialType.PRODUCT;
if (polyType == TernaryPolynomialType.PRODUCT)
{
t = ProductFormPolynomial.FromBinary(KeyStream, n);
}
else
{
IntegerPolynomial fInt = IntegerPolynomial.FromBinary3Tight(KeyStream, n);
if (sparse)
{
t = new SparseTernaryPolynomial(fInt);
}
else
{
t = new DenseTernaryPolynomial(fInt);
}
}
// Initializes fp from t
IntegerPolynomial fp;
if (fastFp)
{
fp = new IntegerPolynomial(n);
fp.Coeffs[0] = 1;
}
else
{
fp = t.ToIntegerPolynomial().InvertF3();
}
return(new NTRUPrivateKey(t, fp, n, q, sparse, fastFp, polyType));
}
catch (IOException ex)
{
throw new NTRUException("NTRUPrivateKey:From", ex.Message, ex);
}
}
public void testFromToBinary()
{
SecureRandom random = new SecureRandom();
SparseTernaryPolynomial poly1 = SparseTernaryPolynomial.GenerateRandom(1000, 100, 101, random);
MemoryStream poly1Stream = new MemoryStream(poly1.ToBinary());
SparseTernaryPolynomial poly2 = SparseTernaryPolynomial.FromBinary(poly1Stream, 1000, 100, 101);
Assert.AreEqual(poly1.GetOnes(), poly2.GetOnes());
Assert.AreEqual(poly1.GetNegOnes(), poly2.GetNegOnes());
Assert.AreEqual(poly1.ToIntegerPolynomial().coeffs, poly2.ToIntegerPolynomial().coeffs);
}
/**
* Generates a "sparse" or "dense" polynomial containing numOnes ints equal to 1,
* numNegOnes int equal to -1, and the rest equal to 0.
*
* @param N
* @param numOnes
* @param numNegOnes
* @param sparse whether to create a {@link SparseTernaryPolynomial} or {@link DenseTernaryPolynomial}
* @return a ternary polynomial
*/
public static ITernaryPolynomial GenerateRandomTernary(int N, int numOnes, int numNegOnes, bool sparse, SecureRandom random)
{
if (sparse)
{
return(SparseTernaryPolynomial.GenerateRandom(N, numOnes, numNegOnes, random));
}
else
{
return(DenseTernaryPolynomial.GenerateRandom(N, numOnes, numNegOnes, random));
}
}
private void FromToBinary()
{
CSPRng rng = new CSPRng();
int N = 1000;
SparseTernaryPolynomial poly1 = SparseTernaryPolynomial.GenerateRandom(N, 100, 101, rng);
MemoryStream poly1Stream = new MemoryStream(poly1.ToBinary());
SparseTernaryPolynomial poly2 = SparseTernaryPolynomial.FromBinary(poly1Stream, N);
if (!Compare.Equals(poly1, poly2))
{
throw new Exception("SparseTernaryPolynomial FromToBinary test failed!");
}
}
private void GenerateRandom()
{
CSPRng rng = new CSPRng();
Verify(SparseTernaryPolynomial.GenerateRandom(743, 248, 248, rng));
for (int i = 0; i < 10; i++)
{
int N = rng.Next(2000) + 10;
int numOnes = rng.Next(N);
int numNegOnes = rng.Next(N - numOnes);
Verify(SparseTernaryPolynomial.GenerateRandom(N, numOnes, numNegOnes, rng));
}
}
/**
* tests mult(IntegerPolynomial) and mult(BigIntPolynomial)
*/
public void testMult()
{
SecureRandom random = new SecureRandom();
SparseTernaryPolynomial p1 = SparseTernaryPolynomial.GenerateRandom(1000, 500, 500, random);
IntegerPolynomial p2 = DenseTernaryPolynomial.GenerateRandom(1000, random);
IntegerPolynomial prod1 = p1.Multiply(p2);
IntegerPolynomial prod2 = p1.Multiply(p2);
Assert.AreEqual(prod1.coeffs, prod2.coeffs);
BigIntPolynomial p3 = new BigIntPolynomial(p2);
BigIntPolynomial prod3 = p1.Multiply(p3);
Assert.AreEqual((new BigIntPolynomial(prod1)).coeffs, prod3.coeffs);
}
private void Verify(SparseTernaryPolynomial poly)
{
// make sure ones and negative ones don't share indices
int[] ones = poly.GetOnes();
int[] nones = poly.GetNegOnes();
for (int i = 0; i < ones.Length; i++)
{
for (int j = 0; j < nones.Length; j++)
{
if (ones[i] == nones[j])
{
throw new Exception("SparseTernaryPolynomial GenerateRandom test failed!");
}
}
}
}
/** tests mult(IntegerPolynomial) and mult(BigIntPolynomial) */
private void MultTest()
{
CSPRng rng = new CSPRng();
SparseTernaryPolynomial p1 = SparseTernaryPolynomial.GenerateRandom(1000, 500, 500, rng);
IntegerPolynomial p2 = PolynomialGeneratorForTesting.generateRandom(1000);
IntegerPolynomial prod1 = p1.Multiply(p2);
prod1 = p1.Multiply(p2);
IntegerPolynomial prod2 = p1.Multiply(p2);
if (!Compare.Equals(prod1, prod2))
{
throw new Exception("SparseTernaryPolynomial multiplication test failed!");
}
BigIntPolynomial p3 = new BigIntPolynomial(p2);
BigIntPolynomial prod3 = p1.Multiply(p3);
if (!Compare.Equals(new BigIntPolynomial(prod1), prod3))
{
throw new Exception("SparseTernaryPolynomial multiplication test failed!");
}
}