versed) 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 1 if a and b are equal and 0 otherwise. func p256Equal(a, b *p256Element) int { var acc uint64 for i := range a { acc |= a[i] ^ b[i] } return uint64IsZero(acc) } // isInfinity returns 1 if p is the point at infinity and 0...