scalar []byte) (*P256Point, error) { if len(scalar) != 32 { return nil, errors.New("invalid scalar length") } scalarReversed := new(p256OrdElement) p256OrdBigToLittle(scalarReversed, (*[32]byte)(scalar)) p256OrdReduce(scalarReversed) r.Set(q).p256ScalarMult(scalarReversed) return r, nil } // uint64IsZero returns 1 if x is zero and zero otherwise. func uint64IsZero(x uint64) int { x = ^x x &= x >> 32 x &= x >> 16 x &= x >> 8 x &= x >> 4 x &= x >> 2 x &= x >> 1 return int(x & 1) } // p256Equal returns...