sets (x, y) to the affine coordinates of p, converted out of the // Montgomery domain. func (p *P256Point) affineFromMont(x, y *p256Element) { p256Inverse(y, &p.z) p256Sqr(x, y, 1) p256Mul(y, y, x) p256Mul(x, &p.x, x) p256Mul(y, &p.y, y) p256FromMont(x, x) p256FromMont(y, y) } // BytesX returns the encoding of the x-coordinate of p, as specified in SEC 1, // Version 2.0, Section 2.3.5, or an error if p is the point at infinity. func (p *P256Point) BytesX() ([]byte, error) { // This function is outlined...