private static bool TrySqrt(uint[] nc, uint[] r, uint[] t)
{
uint[] d1 = Nat224.Create();
Nat224.Copy(r, d1);
uint[] e1 = Nat224.Create();
e1[0] = 1;
uint[] f1 = Nat224.Create();
RP(nc, d1, e1, f1, t);
uint[] d0 = Nat224.Create();
uint[] e0 = Nat224.Create();
for (int k = 1; k < 96; ++k)
{
Nat224.Copy(d1, d0);
Nat224.Copy(e1, e0);
RS(d1, e1, f1, t);
if (Nat224.IsZero(d1))
{
Mod.Invert(SecP224R1Field.P, e0, t);
SecP224R1Field.Multiply(t, d0, t);
return(true);
}
}
return(false);
}
private static void RM(uint[] nc, uint[] d0, uint[] e0, uint[] d1, uint[] e1, uint[] f1, uint[] t)
{
SecP224R1Field.Multiply(e1, e0, t);
SecP224R1Field.Multiply(t, nc, t);
SecP224R1Field.Multiply(d1, d0, f1);
SecP224R1Field.Add(f1, t, f1);
SecP224R1Field.Multiply(d1, e0, t);
Nat224.Copy(f1, d1);
SecP224R1Field.Multiply(e1, d0, e1);
SecP224R1Field.Add(e1, t, e1);
SecP224R1Field.Square(e1, f1);
SecP224R1Field.Multiply(f1, nc, f1);
}
public override ECLookupTable CreateCacheSafeLookupTable(ECPoint[] points, int off, int len)
{
uint[] table = new uint[len * SECP224K1_FE_INTS * 2];
{
int pos = 0;
for (int i = 0; i < len; ++i)
{
ECPoint p = points[off + i];
Nat224.Copy(((SecP224K1FieldElement)p.RawXCoord).x, 0, table, pos); pos += SECP224K1_FE_INTS;
Nat224.Copy(((SecP224K1FieldElement)p.RawYCoord).x, 0, table, pos); pos += SECP224K1_FE_INTS;
}
}
return(new SecP224K1LookupTable(this, table, len));
}
private static bool IsSquare(uint[] x)
{
uint[] t1 = Nat224.Create();
uint[] t2 = Nat224.Create();
Nat224.Copy(x, t1);
for (int i = 0; i < 7; ++i)
{
Nat224.Copy(t1, t2);
SecP224R1Field.SquareN(t1, 1 << i, t1);
SecP224R1Field.Multiply(t1, t2, t1);
}
SecP224R1Field.SquareN(t1, 95, t1);
return(Nat224.IsOne(t1));
}
private static void RP(uint[] nc, uint[] d1, uint[] e1, uint[] f1, uint[] t)
{
Nat224.Copy(nc, f1);
uint[] d0 = Nat224.Create();
uint[] e0 = Nat224.Create();
for (int i = 0; i < 7; ++i)
{
Nat224.Copy(d1, d0);
Nat224.Copy(e1, e0);
int j = 1 << i;
while (--j >= 0)
{
RS(d1, e1, f1, t);
}
RM(nc, d0, e0, d1, e1, f1, t);
}
}
