/**
* return a sqrt root - the routine verifies that the calculation returns the right value - if
* none exists it returns null.
*/
public override ECFieldElement Sqrt()
{
uint[] c = this.x;
if (Nat224.IsZero(c) || Nat224.IsOne(c))
{
return(this);
}
uint[] nc = Nat224.Create();
SecP224R1Field.Negate(c, nc);
uint[] r = Mod.Random(SecP224R1Field.P);
uint[] t = Nat224.Create();
if (!IsSquare(c))
{
return(null);
}
while (!TrySqrt(nc, r, t))
{
SecP224R1Field.AddOne(r, r);
}
SecP224R1Field.Square(t, r);
return(Nat224.Eq(c, r) ? new SecP224R1FieldElement(t) : null);
}
public override ECFieldElement AddOne()
{
uint[] z = Nat224.Create();
SecP224R1Field.AddOne(x, z);
return(new SecP224R1FieldElement(z));
}