private void MultTest()
{
IntegerPolynomial i1 = new IntegerPolynomial(new int[] { 1368, 2047, 672, 871, 1662, 1352, 1099, 1608 });
IntegerPolynomial i2 = new IntegerPolynomial(new int[] { 1729, 1924, 806, 179, 1530, 1381, 1695, 60 });
LongPolynomial2 a = new LongPolynomial2(i1);
LongPolynomial2 b = new LongPolynomial2(i2);
IntegerPolynomial c1 = i1.Multiply(i2, 2048);
IntegerPolynomial c2 = a.Multiply(b).ToIntegerPolynomial();
if (!Compare.AreEqual(c1.Coeffs, c2.Coeffs))
throw new Exception("LongPolynomial2 multiply test failed!");
// test 10 random polynomials
Random rng = new Random();
for (int i = 0; i < 10; i++)
{
int N = 2 + rng.Next(2000);
i1 = (IntegerPolynomial)PolynomialGeneratorForTesting.GenerateRandom(N, 2048);
i2 = (IntegerPolynomial)PolynomialGeneratorForTesting.GenerateRandom(N, 2048);
a = new LongPolynomial2(i1);
b = new LongPolynomial2(i2);
c1 = i1.Multiply(i2);
c1.ModPositive(2048);
c2 = a.Multiply(b).ToIntegerPolynomial();
if (!Compare.AreEqual(c1.Coeffs, c2.Coeffs))
throw new Exception("LongPolynomial2 multiply test failed!");
}
}
/// <summary>
/// Computes the inverse mod <c>q</c> from the inverse mod 2.
/// <para>The algorithm is described in <a href="http://www.securityinnovation.com/uploads/Crypto/NTRUTech014.pdf">
/// Almost Inverses and Fast NTRU Key Generation</a>.</para>
/// </summary>
///
/// <param name="Fq">Fq value</param>
/// <param name="Q">Q value</param>
///
/// <returns>The inverse of this polynomial mod q</returns>
private IntegerPolynomial Mod2ToModq(IntegerPolynomial Fq, int Q)
{
if (SystemUtils.Is64Bit() && Q == 2048)
{
LongPolynomial2 thisLong = new LongPolynomial2(this);
LongPolynomial2 FqLong = new LongPolynomial2(Fq);
int v = 2;
while (v < Q)
{
v *= 2;
LongPolynomial2 temp = FqLong.Clone();
temp.Mult2And(v - 1);
FqLong = thisLong.Multiply(FqLong).Multiply(FqLong);
temp.SubAnd(FqLong, v - 1);
FqLong = temp;
}
return FqLong.ToIntegerPolynomial();
}
else
{
int v = 2;
while (v < Q)
{
v *= 2;
IntegerPolynomial temp = Fq.Clone();
temp.Mult2(v);
Fq = Multiply(Fq, v).Multiply(Fq, v);
temp.Subtract(Fq, v);
Fq = temp;
}
return Fq;
}
}
