equal length) // if v == 1. If v == 0, x is left unchanged. Its behavior is undefined if v // takes any other value. func ConstantTimeCopy(v int, x, y []byte) { if len(x) != len(y) { panic("subtle: slices have different lengths") } xmask := byte(v - 1) ymask := byte(^(v - 1)) for i := 0; i < len(x); i++ { x[i] = x[i]&xmask | y[i]&ymask } } // ConstantTimeLessOrEq returns 1 if x <= y and 0 otherwise. // Its behavior is undefined if x or y are negative or > 2**31 - 1. func ConstantTimeLessOrEq(x, y int)...