private void GenerateFQ(IRandom Rng, out IPolynomial t, out IntegerPolynomial fq, out IntegerPolynomial fp)
{
int N = _encParams.N;
int q = _encParams.Q;
int df = _encParams.DF;
int df1 = _encParams.DF1;
int df2 = _encParams.DF2;
int df3 = _encParams.DF3;
bool fastFp = _encParams.FastFp;
bool sparse = _encParams.Sparse;
TernaryPolynomialType polyType = _encParams.PolyType;
fp = null;
// choose a random f that is invertible mod 3 and q
while (true)
{
IntegerPolynomial f;
// choose random t, calculate f and fp
if (fastFp)
{
// if fastFp=true, f is always invertible mod 3
if (polyType == TernaryPolynomialType.SIMPLE)
{
t = PolynomialGenerator.GenerateRandomTernary(N, df, df, sparse, Rng);
}
else
{
t = ProductFormPolynomial.GenerateRandom(N, df1, df2, df3, df3, Rng);
}
f = t.ToIntegerPolynomial();
f.Multiply(3);
f.Coeffs[0] += 1;
}
else
{
if (polyType == TernaryPolynomialType.SIMPLE)
{
t = PolynomialGenerator.GenerateRandomTernary(N, df, df - 1, sparse, Rng);
}
else
{
t = ProductFormPolynomial.GenerateRandom(N, df1, df2, df3, df3 - 1, Rng);
}
f = t.ToIntegerPolynomial();
fp = f.InvertF3();
if (fp == null)
{
continue;
}
}
fq = f.InvertFq(q);
if (fq != null)
{
break;
}
}
}
private void GenerateFQ(IRandom Rng, out IPolynomial T, out IntegerPolynomial Fq, out IntegerPolynomial Fp)
{
var N = this.m_ntruParams.N;
var q = this.m_ntruParams.Q;
var df = this.m_ntruParams.DF;
var df1 = this.m_ntruParams.DF1;
var df2 = this.m_ntruParams.DF2;
var df3 = this.m_ntruParams.DF3;
var fastFp = this.m_ntruParams.FastFp;
var sparse = this.m_ntruParams.Sparse;
var polyType = this.m_ntruParams.PolyType;
Fp = null;
// choose a random f that is invertible mod 3 and q
while (true)
{
IntegerPolynomial f;
// choose random t, calculate f and fp
if (fastFp)
{
// if fastFp=true, f is always invertible mod 3
if (polyType == TernaryPolynomialType.SIMPLE)
{
T = PolynomialGenerator.GenerateRandomTernary(N, df, df, sparse, Rng);
}
else
{
T = ProductFormPolynomial.GenerateRandom(N, df1, df2, df3, df3, Rng);
}
f = T.ToIntegerPolynomial();
f.Multiply(3);
f.Coeffs[0] += 1;
}
else
{
if (polyType == TernaryPolynomialType.SIMPLE)
{
T = PolynomialGenerator.GenerateRandomTernary(N, df, df - 1, sparse, Rng);
}
else
{
T = ProductFormPolynomial.GenerateRandom(N, df1, df2, df3, df3 - 1, Rng);
}
f = T.ToIntegerPolynomial();
Fp = f.InvertF3();
if (Fp == null)
{
continue;
}
}
Fq = f.InvertFq(q);
if (Fq != null)
{
break;
}
}
}