/**
* return a sqrt root - the routine verifies that the calculation returns the right value - if
* none exists it returns null.
*/
public override ECFieldElement Sqrt()
{
// Raise this element to the exponent 2^519
uint[] x1 = this.x;
if (Nat.IsZero(17, x1) || Nat.IsOne(17, x1))
{
return(this);
}
uint[] t1 = Nat.Create(17);
uint[] t2 = Nat.Create(17);
SecP521R1Field.SquareN(x1, 519, t1);
SecP521R1Field.Square(t1, t2);
return(Nat.Eq(17, x1, t2) ? new SecP521R1FieldElement(t1) : null);
}
