codekingpro/portable-devtools

1// Copyright 2009 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4 5// Package subtle implements functions that are often useful in cryptographic6// code but require careful thought to use correctly.7package subtle8 9import (10	"crypto/internal/constanttime"11	"crypto/internal/fips140/subtle"12)13 14// These functions are forwarded to crypto/internal/constanttime for intrinsified15// operations, and to crypto/internal/fips140/subtle for byte slice operations.16 17// ConstantTimeCompare returns 1 if the two slices, x and y, have equal contents18// and 0 otherwise. The time taken is a function of the length of the slices and19// is independent of the contents. If the lengths of x and y do not match it20// returns 0 immediately.21func ConstantTimeCompare(x, y []byte) int {22	return subtle.ConstantTimeCompare(x, y)23}24 25// ConstantTimeSelect returns x if v == 1 and y if v == 0.26// Its behavior is undefined if v takes any other value.27func ConstantTimeSelect(v, x, y int) int {28	return constanttime.Select(v, x, y)29}30 31// ConstantTimeByteEq returns 1 if x == y and 0 otherwise.32func ConstantTimeByteEq(x, y uint8) int {33	return constanttime.ByteEq(x, y)34}35 36// ConstantTimeEq returns 1 if x == y and 0 otherwise.37func ConstantTimeEq(x, y int32) int {38	return constanttime.Eq(x, y)39}40 41// ConstantTimeCopy copies the contents of y into x (a slice of equal length)42// if v == 1. If v == 0, x is left unchanged. Its behavior is undefined if v43// takes any other value.44func ConstantTimeCopy(v int, x, y []byte) {45	subtle.ConstantTimeCopy(v, x, y)46}47 48// ConstantTimeLessOrEq returns 1 if x <= y and 0 otherwise.49// Its behavior is undefined if x or y are negative or > 2**31 - 1.50func ConstantTimeLessOrEq(x, y int) int {51	return constanttime.LessOrEq(x, y)52}53