需求
前端/后端使用
国密SM4进行加密/解密，
【注意】前后端配合加解密时，需要我们自定义密钥，一般由后端提供
【方法1】 - 使用 sm4util 依赖
-
下载
sm4util依赖npm install sm4util -
sm4util 依赖使用说明
-
使用 - ECB 模式加解密
/**** 【1】导入依赖 ****/ import { SM4Util } from 'sm4util' /**** 【2】使用（在改依赖中有使用说明） ****/ // 1.使用默认密钥进行加密/解密 var sm4 = new SM4Util() const miStr1 = sm4.encryptDefault_ECB('123') // sm4.encryptDefault_ECB(需要加密的字符串) console.log('miStr1----', miStr1) const jieStr1 = sm4.decryptDefault_ECB(miStr1) // sm4.decryptDefault_ECB(将字符串进行加密后生成的字符串) console.log('jieStr1----', jieStr1) // 123 // 2.使用自定义密钥进行加密/解密（【注意】使用自定义密钥进行加密时，后端解密需要用相同的密钥进行解密 - 此处密钥可能不对） // var sm4 = new SM4Util() const miStr2 = sm4.encryptCustom_ECB('123', '93F3044B07393417A737E2***389D01AF') // 加密 sm4.encryptCustom_ECB(需要加密的字符串, 密钥) console.log('miStr2----', miStr2) const jieStr2 = sm4.decryptCustom_ECB(miStr2, '93F3044B07393417A737E2***389D01AF') // 解密 sm4.decryptCustom_ECB(将字符串进行加密后生成的字符串, 密钥) console.log('jieStr2----', jieStr2) // 123
后端代码参考：https://blog.csdn.***/qq_48922459/article/details/122130283
【方法2】sm4.js引入
这种办法好像只能使用默认密钥 key，不能自定义 key 我使用的自定义 key 会报错
"key error"（也有可能是我的 密钥不对）
我使用自定义密钥 - 得改sm4.js 代码，详见SM4Util 函数定义处被注释的代码
1. /public/sm4.js
/**
* base64js
* base64js.toByteArray(d.input)
* base64js.fromByteArray(c);
* 国密SM4加密算法
*/
;(function (r) {
if (typeof exports === 'object' && typeof module !== 'undefined') {
module.exports = r()
} else {
if (typeof define === 'function' && define.amd) {
define([], r)
} else {
var e
if (typeof window !== 'undefined') {
e = window
} else {
if (typeof global !== 'undefined') {
e = global
} else {
if (typeof self !== 'undefined') {
e = self
} else {
e = this
}
}
}
e.base64js = r()
}
}
})(function () {
var r, e, t
return (function r(e, t, n) {
function o(i, a) {
if (!t[i]) {
if (!e[i]) {
var u = typeof require == 'function' && require
if (!a && u) {
return u(i, !0)
}
if (f) {
return f(i, !0)
}
var d = new Error("Cannot find module '" + i + "'")
throw ((d.code = 'MODULE_NOT_FOUND'), d)
}
var c = (t[i] = { exports: {} })
e[i][0].call(
c.exports,
function (r) {
var t = e[i][1][r]
return o(t ? t : r)
},
c,
c.exports,
r,
e,
t,
n
)
}
return t[i].exports
}
var f = typeof require == 'function' && require
for (var i = 0; i < n.length; i++) {
o(n[i])
}
return o
})(
{
'/': [
function (r, e, t) {
t.byteLength = c
t.toByteArray = v
t.fromByteArray = s
var n = []
var o = []
var f = typeof Uint8Array !== 'undefined' ? Uint8Array : Array
var i = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var a = 0, u = i.length; a < u; ++a) {
n[a] = i[a]
o[i.charCodeAt(a)] = a
}
o['-'.charCodeAt(0)] = 62
o['_'.charCodeAt(0)] = 63
function d(r) {
var e = r.length
if (e % 4 > 0) {
throw new Error('Invalid string. Length must be a multiple of 4')
}
return r[e - 2] === '=' ? 2 : r[e - 1] === '=' ? 1 : 0
}
function c(r) {
return (r.length * 3) / 4 - d(r)
}
function v(r) {
var e, t, n, i, a
var u = r.length
i = d(r)
a = new f((u * 3) / 4 - i)
t = i > 0 ? u - 4 : u
var c = 0
for (e = 0; e < t; e += 4) {
n =
(o[r.charCodeAt(e)] << 18) |
(o[r.charCodeAt(e + 1)] << 12) |
(o[r.charCodeAt(e + 2)] << 6) |
o[r.charCodeAt(e + 3)]
a[c++] = (n >> 16) & 255
a[c++] = (n >> 8) & 255
a[c++] = n & 255
}
if (i === 2) {
n = (o[r.charCodeAt(e)] << 2) | (o[r.charCodeAt(e + 1)] >> 4)
a[c++] = n & 255
} else {
if (i === 1) {
n = (o[r.charCodeAt(e)] << 10) | (o[r.charCodeAt(e + 1)] << 4) | (o[r.charCodeAt(e + 2)] >> 2)
a[c++] = (n >> 8) & 255
a[c++] = n & 255
}
}
return a
}
function l(r) {
return n[(r >> 18) & 63] + n[(r >> 12) & 63] + n[(r >> 6) & 63] + n[r & 63]
}
function h(r, e, t) {
var n
var o = []
for (var f = e; f < t; f += 3) {
n = (r[f] << 16) + (r[f + 1] << 8) + r[f + 2]
o.push(l(n))
}
return o.join('')
}
function s(r) {
var e
var t = r.length
var o = t % 3
var f = ''
var i = []
var a = 16383
for (var u = 0, d = t - o; u < d; u += a) {
i.push(h(r, u, u + a > d ? d : u + a))
}
if (o === 1) {
e = r[t - 1]
f += n[e >> 2]
f += n[(e << 4) & 63]
f += '=='
} else {
if (o === 2) {
e = (r[t - 2] << 8) + r[t - 1]
f += n[e >> 10]
f += n[(e >> 4) & 63]
f += n[(e << 2) & 63]
f += '='
}
}
i.push(f)
return i.join('')
}
},
{}
]
},
{},
[]
)('/')
})
/**
* 国密SM4加密算法
* @author wzk
* @email 1216113487@qq.***
* @***pany 中科软
*/
function SM4_Context() {
this.mode = 1
this.isPadding = true
this.sk = new Array(32)
}
function SM4() {
this.SM4_ENCRYPT = 1
this.SM4_DECRYPT = 0
var SboxTable = [
0xd6, 0x90, 0xe9, 0xfe, 0x***, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05, 0x2b, 0x67, 0x9a,
0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99, 0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef,
0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62, 0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80,
0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6, 0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19,
0xe6, 0x85, 0x4f, 0xa8, 0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d,
0x35, 0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87, 0xd4, 0x00,
0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e, 0xea, 0xbf, 0x8a, 0xd2, 0x40,
0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1, 0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3, 0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23,
0xab, 0x0d, 0x53, 0x4e, 0x6f, 0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c,
0x5b, 0x51, 0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8, 0x0a,
0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0, 0x89, 0x69, 0x97, 0x4a,
0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84, 0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d,
0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
]
var FK = [0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc]
var CK = [
0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269, 0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9, 0xe0e7eef5,
0xfc030a11, 0x181f262d, 0x343b4249, 0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9, 0xc0c7ced5, 0xdce3eaf1,
0xf8ff060d, 0x141b2229, 0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299, 0xa0a7aeb5, 0xb***3cad1, 0xd8dfe6ed,
0xf4fb0209, 0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
]
this.GET_ULONG_BE = function (b, i) {
return ((b[i] & 0xff) << 24) | ((b[i + 1] & 0xff) << 16) | ((b[i + 2] & 0xff) << 8) | (b[i + 3] & 0xff & 0xffffffff)
}
this.PUT_ULONG_BE = function (n, b, i) {
var t1 = 0xff & (n >> 24)
var t2 = 0xff & (n >> 16)
var t3 = 0xff & (n >> 8)
var t4 = 0xff & n
b[i] = t1 > 128 ? t1 - 256 : t1
b[i + 1] = t2 > 128 ? t2 - 256 : t2
b[i + 2] = t3 > 128 ? t3 - 256 : t3
b[i + 3] = t4 > 128 ? t4 - 256 : t4
}
this.SHL = function (x, n) {
return (x & 0xffffffff) << n
}
this.ROTL = function (x, n) {
var s = this.SHL(x, n)
var ss = x >> (32 - n)
return this.SHL(x, n) | (x >> (32 - n))
}
this.sm4Lt = function (ka) {
var bb = 0
var c = 0
var a = new Array(4)
var b = new Array(4)
this.PUT_ULONG_BE(ka, a, 0)
b[0] = this.sm4Sbox(a[0])
b[1] = this.sm4Sbox(a[1])
b[2] = this.sm4Sbox(a[2])
b[3] = this.sm4Sbox(a[3])
bb = this.GET_ULONG_BE(b, 0)
c = bb ^ this.ROTL(bb, 2) ^ this.ROTL(bb, 10) ^ this.ROTL(bb, 18) ^ this.ROTL(bb, 24)
return c
}
this.sm4F = function (x0, x1, x2, x3, rk) {
return x0 ^ this.sm4Lt(x1 ^ x2 ^ x3 ^ rk)
}
this.sm4CalciRK = function (ka) {
var bb = 0
var rk = 0
var a = new Array(4)
var b = new Array(4)
this.PUT_ULONG_BE(ka, a, 0)
b[0] = this.sm4Sbox(a[0])
b[1] = this.sm4Sbox(a[1])
b[2] = this.sm4Sbox(a[2])
b[3] = this.sm4Sbox(a[3])
bb = this.GET_ULONG_BE(b, 0)
rk = bb ^ this.ROTL(bb, 13) ^ this.ROTL(bb, 23)
return rk
}
this.sm4Sbox = function (inch) {
var i = inch & 0xff
var retVal = SboxTable[i]
return retVal > 128 ? retVal - 256 : retVal
}
this.sm4_setkey_enc = function (ctx, key) {
if (ctx == null) {
alert('ctx is null!')
return false
}
console.log('key----', key)
if (key == null || key.length != 16) {
alert('key error!')
return false
}
ctx.mode = this.SM4_ENCRYPT
this.sm4_setkey(ctx.sk, key)
}
this.sm4_setkey = function (SK, key) {
var MK = new Array(4)
var k = new Array(36)
var i = 0
MK[0] = this.GET_ULONG_BE(key, 0)
MK[1] = this.GET_ULONG_BE(key, 4)
MK[2] = this.GET_ULONG_BE(key, 8)
MK[3] = this.GET_ULONG_BE(key, 12)
k[0] = MK[0] ^ FK[0]
k[1] = MK[1] ^ FK[1]
k[2] = MK[2] ^ FK[2]
k[3] = MK[3] ^ FK[3]
for (var i = 0; i < 32; i++) {
k[i + 4] = k[i] ^ this.sm4CalciRK(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i])
SK[i] = k[i + 4]
}
}
this.padding = function (input, mode) {
if (input == null) {
return null
}
var ret = null
if (mode == this.SM4_ENCRYPT) {
var p = parseInt(16 - (input.length % 16))
ret = input.slice(0)
for (var i = 0; i < p; i++) {
ret[input.length + i] = p
}
} else {
var p = input[input.length - 1]
ret = input.slice(0, input.length - p)
}
return ret
}
this.sm4_one_round = function (sk, input, output) {
var i = 0
var ulbuf = new Array(36)
ulbuf[0] = this.GET_ULONG_BE(input, 0)
ulbuf[1] = this.GET_ULONG_BE(input, 4)
ulbuf[2] = this.GET_ULONG_BE(input, 8)
ulbuf[3] = this.GET_ULONG_BE(input, 12)
while (i < 32) {
ulbuf[i + 4] = this.sm4F(ulbuf[i], ulbuf[i + 1], ulbuf[i + 2], ulbuf[i + 3], sk[i])
i++
}
this.PUT_ULONG_BE(ulbuf[35], output, 0)
this.PUT_ULONG_BE(ulbuf[34], output, 4)
this.PUT_ULONG_BE(ulbuf[33], output, 8)
this.PUT_ULONG_BE(ulbuf[32], output, 12)
}
this.sm4_crypt_ecb = function (ctx, input) {
if (input == null) {
alert('input is null!')
}
if (ctx.isPadding && ctx.mode == this.SM4_ENCRYPT) {
input = this.padding(input, this.SM4_ENCRYPT)
}
var i = 0
var length = input.length
var bous = new Array()
for (; length > 0; length -= 16) {
var out = new Array(16)
var ins = input.slice(i * 16, 16 * (i + 1))
this.sm4_one_round(ctx.sk, ins, out)
bous = bous.concat(out)
i++
}
var output = bous
if (ctx.isPadding && ctx.mode == this.SM4_DECRYPT) {
output = this.padding(output, this.SM4_DECRYPT)
}
for (var i = 0; i < output.length; i++) {
if (output[i] < 0) {
output[i] = output[i] + 256
}
}
return output
}
this.sm4_crypt_cbc = function (ctx, iv, input) {
if (iv == null || iv.length != 16) {
alert('iv error!')
}
if (input == null) {
alert('input is null!')
}
if (ctx.isPadding && ctx.mode == this.SM4_ENCRYPT) {
input = this.padding(input, this.SM4_ENCRYPT)
}
var i = 0
var length = input.length
var bous = new Array()
if (ctx.mode == this.SM4_ENCRYPT) {
var k = 0
for (; length > 0; length -= 16) {
var out = new Array(16)
var out1 = new Array(16)
var ins = input.slice(k * 16, 16 * (k + 1))
for (i = 0; i < 16; i++) {
out[i] = ins[i] ^ iv[i]
}
this.sm4_one_round(ctx.sk, out, out1)
iv = out1.slice(0, 16)
bous = bous.concat(out1)
k++
}
} else {
var temp = []
var k = 0
for (; length > 0; length -= 16) {
var out = new Array(16)
var out1 = new Array(16)
var ins = input.slice(k * 16, 16 * (k + 1))
temp = ins.slice(0, 16)
sm4_one_round(ctx.sk, ins, out)
for (i = 0; i < 16; i++) {
out1[i] = out[i] ^ iv[i]
}
iv = temp.slice(0, 16)
bous = bous.concat(out1)
k++
}
}
var output = bous
if (ctx.isPadding && ctx.mode == this.SM4_DECRYPT) {
output = this.padding(output, this.SM4_DECRYPT)
}
for (var i = 0; i < output.length; i++) {
if (output[i] < 0) {
output[i] = output[i] + 256
}
}
return output
}
}
// function SM4Util(key = '1111111111111111') {
function SM4Util() {
console.log('SM4Util key----', key)
// 和后端key一致（key为密钥）
// this.secretKey = key
this.secretKey = '1111111111111111'
// 当时用CBC模式的时候
this.iv = '1111111111111111'
this.hexString = false
// ECB模式加密
this.encryptData_ECB = function (plainText) {
try {
var sm4 = new SM4()
var ctx = new SM4_Context()
ctx.isPadding = true
ctx.mode = sm4.SM4_ENCRYPT
var keyBytes = stringToByte(this.secretKey)
sm4.sm4_setkey_enc(ctx, keyBytes)
var encrypted = sm4.sm4_crypt_ecb(ctx, stringToByte(plainText))
var cipherText = base64js.fromByteArray(encrypted)
if (cipherText != null && cipherText.trim().length > 0) {
cipherText.replace(/(\s*|\t|\r|\n)/g, '')
}
return cipherText
} catch (e) {
console.error(e)
return null
}
}
// CBC模式加密
this.encryptData_CBC = function (plainText) {
try {
var sm4 = new SM4()
var ctx = new SM4_Context()
ctx.isPadding = true
ctx.mode = sm4.SM4_ENCRYPT
var keyBytes = stringToByte(this.secretKey)
var ivBytes = stringToByte(this.iv)
sm4.sm4_setkey_enc(ctx, keyBytes)
var encrypted = sm4.sm4_crypt_cbc(ctx, ivBytes, stringToByte(plainText))
var cipherText = base64js.fromByteArray(encrypted)
if (cipherText != null && cipherText.trim().length > 0) {
cipherText.replace(/(\s*|\t|\r|\n)/g, '')
}
return cipherText
} catch (e) {
console.error(e)
return null
}
}
stringToByte = function (str) {
var bytes = new Array()
var len, c
len = str.length
for (var i = 0; i < len; i++) {
c = str.charCodeAt(i)
if (c >= 0x010000 && c <= 0x10ffff) {
bytes.push(((c >> 18) & 0x07) | 0xf0)
bytes.push(((c >> 12) & 0x3f) | 0x80)
bytes.push(((c >> 6) & 0x3f) | 0x80)
bytes.push((c & 0x3f) | 0x80)
} else if (c >= 0x000800 && c <= 0x00ffff) {
bytes.push(((c >> 12) & 0x0f) | 0xe0)
bytes.push(((c >> 6) & 0x3f) | 0x80)
bytes.push((c & 0x3f) | 0x80)
} else if (c >= 0x000080 && c <= 0x0007ff) {
bytes.push(((c >> 6) & 0x1f) | 0xc0)
bytes.push((c & 0x3f) | 0x80)
} else {
bytes.push(c & 0xff)
}
}
console.log('bytes----', bytes)
return bytes
}
byteToString = function (arr) {
if (typeof arr === 'string') {
return arr
}
var str = '',
_arr = arr
for (var i = 0; i < _arr.length; i++) {
var one = _arr[i].toString(2),
v = one.match(/^1+?(?=0)/)
if (v && one.length == 8) {
var bytesLength = v[0].length
var store = _arr[i].toString(2).slice(7 - bytesLength)
for (var st = 1; st < bytesLength; st++) {
store += _arr[st + i].toString(2).slice(2)
}
str += String.fromCharCode(parseInt(store, 2))
i += bytesLength - 1
} else {
str += String.fromCharCode(_arr[i])
}
}
return str
}
}
2. body 标签上引入该文件
<script src="/sm4.js"></script>
<body></body>
3. 使用 - ECB 模式加密
// 加密 - 使用默认秘钥 1111111111111111
var sm4 = new SM4Util();
sm4.encryptData_ECB('123');
// 加密 - 使用自定义秘钥 93F3044B07393417A737E2***389D01AF （需将 sm4.js 文件中SM4Util 函数处注释的代码打开）
var sm4 = new SM4Util('93F3044B07393417A737E2***389D01AF');
sm4.encryptData_ECB('123'); // 后端解密的好像对不上，
该加密办法参考博客 https://blog.csdn.***/wzk_blog/article/details/122668114
【方法3】
1. 本地写 js 文件
@/utils/SM4Util/index.js
let base64js = require('./base64js')
let Hex = require('./hex')
let SM4 = require('./sm4')
function SM4Util() {}
/**
* sm4 ecb 加密
* @param utf8Str
* @param utf8Key
*/
SM4Util.sm4ECBEncrypt = function (utf8Str, utf8Key) {
if (!utf8Key) {
utf8Key = 'zzfh!@#$QazxWsxc'
}
let sm4 = new SM4()
let keyBytes = Hex.utf8StrToBytes(utf8Key)
let contentBytes = Hex.utf8StrToBytes(utf8Str)
let cipher = sm4.encrypt_ecb(keyBytes, contentBytes)
return base64js.fromByteArray(cipher)
}
/**
* sm4 ecb 解密
* @param utf8Str
* @param utf8Key
*/
SM4Util.sm4ECBDecrypt = function (base64Str, utf8Key) {
if (!utf8Key) {
utf8Key = 'zzfh!@#$QazxWsxc'
}
let sm4 = new SM4()
let keyBytes = Hex.utf8StrToBytes(utf8Key)
let contentBytes = base64js.toByteArray(base64Str)
let plain = sm4.decrypt_ecb(keyBytes, contentBytes)
return Hex.bytesToUtf8Str(plain)
}
/**
* sm4 cbc 加密
* @param utf8Str
* @param utf8Key
* @param utf8Iv
*/
SM4Util.sm4CBCEncrypt = function (utf8Str, utf8Key, utf8Iv) {
if (!utf8Key) {
utf8Key = 'cmbtest1cmbtest1'
}
if (!utf8Iv) {
utf8Iv = 'cmbtest1cmbtest1'
}
let sm4 = new SM4()
let keyBytes = Hex.utf8StrToBytes(utf8Key)
let ivBytes = Hex.utf8StrToBytes(utf8Iv)
let contentBytes = Hex.utf8StrToBytes(utf8Str)
let cipher = sm4.encrypt_cbc(keyBytes, ivBytes, contentBytes)
return base64js.fromByteArray(cipher)
}
/**
* sm4 cbc 解密
* @param utf8Str
* @param utf8Key
* @param utf8Iv
*/
SM4Util.sm4CBCDecrypt = function (base64Str, utf8Key, utf8Iv) {
if (!utf8Key) {
utf8Key = 'cmbtest1cmbtest1'
}
if (!utf8Iv) {
utf8Iv = 'cmbtest1cmbtest1'
}
let sm4 = new SM4()
let keyBytes = Hex.utf8StrToBytes(utf8Key)
let ivBytes = Hex.utf8StrToBytes(utf8Iv)
let contentBytes = base64js.toByteArray(base64Str)
let plain = sm4.decrypt_cbc(keyBytes, ivBytes, contentBytes)
return Hex.bytesToUtf8Str(plain)
}
module.exports = SM4Util
@/utils/SM4Util/base64js.js
/**
* base64js
* base64js.toByteArray(utf8Str)
* base64js.fromByteArray(bytes);
*/
;(function (r) {
if (typeof exports === 'object' && typeof module !== 'undefined') {
module.exports = r()
} else {
if (typeof define === 'function' && define.amd) {
define([], r)
} else {
var e
if (typeof window !== 'undefined') {
e = window
} else {
if (typeof global !== 'undefined') {
e = global
} else {
if (typeof self !== 'undefined') {
e = self
} else {
e = this
}
}
}
e.base64js = r()
}
}
})(function () {
var r, e, t
return (function r(e, t, n) {
function o(i, a) {
if (!t[i]) {
if (!e[i]) {
var u = typeof require == 'function' && require
if (!a && u) {
return u(i, !0)
}
if (f) {
return f(i, !0)
}
var d = new Error("Cannot find module '" + i + "'")
throw ((d.code = 'MODULE_NOT_FOUND'), d)
}
var c = (t[i] = {
exports: {}
})
e[i][0].call(
c.exports,
function (r) {
var t = e[i][1][r]
return o(t ? t : r)
},
c,
c.exports,
r,
e,
t,
n
)
}
return t[i].exports
}
var f = typeof require == 'function' && require
for (var i = 0; i < n.length; i++) {
o(n[i])
}
return o
})(
{
'/': [
function (r, e, t) {
t.byteLength = c
t.toByteArray = v
t.fromByteArray = s
var n = []
var o = []
var f = typeof Uint8Array !== 'undefined' ? Uint8Array : Array
var i = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var a = 0, u = i.length; a < u; ++a) {
n[a] = i[a]
o[i.charCodeAt(a)] = a
}
o['-'.charCodeAt(0)] = 62
o['_'.charCodeAt(0)] = 63
function d(r) {
var e = r.length
if (e % 4 > 0) {
throw new Error('Invalid string. Length must be a multiple of 4')
}
return r[e - 2] === '=' ? 2 : r[e - 1] === '=' ? 1 : 0
}
function c(r) {
return (r.length * 3) / 4 - d(r)
}
function v(r) {
var e, t, n, i, a
var u = r.length
i = d(r)
a = new f((u * 3) / 4 - i)
t = i > 0 ? u - 4 : u
var c = 0
for (e = 0; e < t; e += 4) {
n =
(o[r.charCodeAt(e)] << 18) |
(o[r.charCodeAt(e + 1)] << 12) |
(o[r.charCodeAt(e + 2)] << 6) |
o[r.charCodeAt(e + 3)]
a[c++] = (n >> 16) & 255
a[c++] = (n >> 8) & 255
a[c++] = n & 255
}
if (i === 2) {
n = (o[r.charCodeAt(e)] << 2) | (o[r.charCodeAt(e + 1)] >> 4)
a[c++] = n & 255
} else {
if (i === 1) {
n = (o[r.charCodeAt(e)] << 10) | (o[r.charCodeAt(e + 1)] << 4) | (o[r.charCodeAt(e + 2)] >> 2)
a[c++] = (n >> 8) & 255
a[c++] = n & 255
}
}
return a
}
function l(r) {
return n[(r >> 18) & 63] + n[(r >> 12) & 63] + n[(r >> 6) & 63] + n[r & 63]
}
function h(r, e, t) {
var n
var o = []
for (var f = e; f < t; f += 3) {
n = (r[f] << 16) + (r[f + 1] << 8) + r[f + 2]
o.push(l(n))
}
return o.join('')
}
function s(r) {
var e
var t = r.length
var o = t % 3
var f = ''
var i = []
var a = 16383
for (var u = 0, d = t - o; u < d; u += a) {
i.push(h(r, u, u + a > d ? d : u + a))
}
if (o === 1) {
e = r[t - 1]
f += n[e >> 2]
f += n[(e << 4) & 63]
f += '=='
} else {
if (o === 2) {
e = (r[t - 2] << 8) + r[t - 1]
f += n[e >> 10]
f += n[(e >> 4) & 63]
f += n[(e << 2) & 63]
f += '='
}
}
i.push(f)
return i.join('')
}
},
{}
]
},
{},
[]
)('/')
})
@/utils/SM4Util/hex.js
function Hex() {}
/**
* 数组转为16进制字符串
* @param b 数组
* @param pos 指定位置
* @param len 长度
* @returns {string}
*/
Hex.encode = function (b, pos, len) {
var hexCh = new Array(len * 2)
var hexCode = new Array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F')
for (var i = pos, j = 0; i < len + pos; i++, j++) {
hexCh[j] = hexCode[(b[i] & 0xff) >> 4]
hexCh[++j] = hexCode[b[i] & 0x0f]
}
return hexCh.join('')
}
/**
* 16进制字符串转为字节数组
* @param hex
* @returns {any[]|null}
*/
Hex.decode = function (hex) {
if (hex == null || hex == '') {
return null
}
if (hex.length % 2 != 0) {
return null
}
var ascLen = hex.length / 2
var hexCh = this.toCharCodeArray(hex)
var asc = new Array(ascLen)
for (var i = 0; i < ascLen; i++) {
if (hexCh[2 * i] >= 0x30 && hexCh[2 * i] <= 0x39) {
asc[i] = (hexCh[2 * i] - 0x30) << 4
} else if (hexCh[2 * i] >= 0x41 && hexCh[2 * i] <= 0x46) {
//A-F : 0x41-0x46
asc[i] = (hexCh[2 * i] - 0x41 + 10) << 4
} else if (hexCh[2 * i] >= 0x61 && hexCh[2 * i] <= 0x66) {
//a-f : 0x61-0x66
asc[i] = (hexCh[2 * i] - 0x61 + 10) << 4
} else {
return null
}
if (hexCh[2 * i + 1] >= 0x30 && hexCh[2 * i + 1] <= 0x39) {
asc[i] = asc[i] | (hexCh[2 * i + 1] - 0x30)
} else if (hexCh[2 * i + 1] >= 0x41 && hexCh[2 * i + 1] <= 0x46) {
asc[i] = asc[i] | (hexCh[2 * i + 1] - 0x41 + 10)
} else if (hexCh[2 * i + 1] >= 0x61 && hexCh[2 * i + 1] <= 0x66) {
asc[i] = asc[i] | (hexCh[2 * i + 1] - 0x61 + 10)
} else {
return null
}
}
return asc
}
/**
* utf8字符串转为字节数组
* @param utf8Str
* @returns {[]}
*/
Hex.utf8StrToBytes = function (utf8Str) {
var ens = encodeURI***ponent(utf8Str)
var es = unescape(ens)
var esLen = es.length
// Convert
var words = []
for (var i = 0; i < esLen; i++) {
words[i] = es.charCodeAt(i)
}
return words
}
/**
* 字节数组转为utf8字符串
* @param bytesArray
* @returns {string}
*/
Hex.bytesToUtf8Str = function (bytesArray) {
var utf8Byte = bytesArray
var latin1Chars = []
for (var i = 0; i < utf8Byte.length; i++) {
latin1Chars.push(String.fromCharCode(utf8Byte[i]))
}
return decodeURI***ponent(escape(latin1Chars.join('')))
}
/**
* 16进制字符串转为utf8字符串
* @param utf8Str
* @returns {string}
*/
Hex.hexToUtf8Str = function (utf8Str) {
var utf8Byte = Hex.decode(utf8Str)
var latin1Chars = []
for (var i = 0; i < utf8Byte.length; i++) {
latin1Chars.push(String.fromCharCode(utf8Byte[i]))
}
return decodeURI***ponent(escape(latin1Chars.join('')))
}
/**
* utf8字符串转为16进制字符串
* @param utf8Str
* @returns {string}
*/
Hex.utf8StrToHex = function (utf8Str) {
var ens = encodeURI***ponent(utf8Str)
var es = unescape(ens)
var esLen = es.length
// Convert
var words = []
for (var i = 0; i < esLen; i++) {
words[i] = es.charCodeAt(i).toString(16)
}
return words.join('')
}
/**
* 字符串中每个字符转为数组中每个元素，数字，字母同Hex.utf8StrToBytes()方法
* @param chs
* @returns {any[]}
*/
Hex.toCharCodeArray = function (chs) {
var chArr = new Array(chs.length)
for (var i = 0; i < chs.length; i++) {
chArr[i] = chs.charCodeAt(i)
}
return chArr
}
module.exports = Hex
@/utils/SM4Util/sm4.js
/*
* sm4-1.0.js
*
* Copyright (c) 2019 RuXing Liang
*/
/**
* @name sm4-1.0.js
* @author RuXing Liang
* @version 1.0.0 (2019-04-19)
*/
function SM4() {
this.sbox = new Array(
0xd6,
0x90,
0xe9,
0xfe,
0x***,
0xe1,
0x3d,
0xb7,
0x16,
0xb6,
0x14,
0xc2,
0x28,
0xfb,
0x2c,
0x05,
0x2b,
0x67,
0x9a,
0x76,
0x2a,
0xbe,
0x04,
0xc3,
0xaa,
0x44,
0x13,
0x26,
0x49,
0x86,
0x06,
0x99,
0x9c,
0x42,
0x50,
0xf4,
0x91,
0xef,
0x98,
0x7a,
0x33,
0x54,
0x0b,
0x43,
0xed,
0xcf,
0xac,
0x62,
0xe4,
0xb3,
0x1c,
0xa9,
0xc9,
0x08,
0xe8,
0x95,
0x80,
0xdf,
0x94,
0xfa,
0x75,
0x8f,
0x3f,
0xa6,
0x47,
0x07,
0xa7,
0xfc,
0xf3,
0x73,
0x17,
0xba,
0x83,
0x59,
0x3c,
0x19,
0xe6,
0x85,
0x4f,
0xa8,
0x68,
0x6b,
0x81,
0xb2,
0x71,
0x64,
0xda,
0x8b,
0xf8,
0xeb,
0x0f,
0x4b,
0x70,
0x56,
0x9d,
0x35,
0x1e,
0x24,
0x0e,
0x5e,
0x63,
0x58,
0xd1,
0xa2,
0x25,
0x22,
0x7c,
0x3b,
0x01,
0x21,
0x78,
0x87,
0xd4,
0x00,
0x46,
0x57,
0x9f,
0xd3,
0x27,
0x52,
0x4c,
0x36,
0x02,
0xe7,
0xa0,
0xc4,
0xc8,
0x9e,
0xea,
0xbf,
0x8a,
0xd2,
0x40,
0xc7,
0x38,
0xb5,
0xa3,
0xf7,
0xf2,
0xce,
0xf9,
0x61,
0x15,
0xa1,
0xe0,
0xae,
0x5d,
0xa4,
0x9b,
0x34,
0x1a,
0x55,
0xad,
0x93,
0x32,
0x30,
0xf5,
0x8c,
0xb1,
0xe3,
0x1d,
0xf6,
0xe2,
0x2e,
0x82,
0x66,
0xca,
0x60,
0xc0,
0x29,
0x23,
0xab,
0x0d,
0x53,
0x4e,
0x6f,
0xd5,
0xdb,
0x37,
0x45,
0xde,
0xfd,
0x8e,
0x2f,
0x03,
0xff,
0x6a,
0x72,
0x6d,
0x6c,
0x5b,
0x51,
0x8d,
0x1b,
0xaf,
0x92,
0xbb,
0xdd,
0xbc,
0x7f,
0x11,
0xd9,
0x5c,
0x41,
0x1f,
0x10,
0x5a,
0xd8,
0x0a,
0xc1,
0x31,
0x88,
0xa5,
0xcd,
0x7b,
0xbd,
0x2d,
0x74,
0xd0,
0x12,
0xb8,
0xe5,
0xb4,
0xb0,
0x89,
0x69,
0x97,
0x4a,
0x0c,
0x96,
0x77,
0x7e,
0x65,
0xb9,
0xf1,
0x09,
0xc5,
0x6e,
0xc6,
0x84,
0x18,
0xf0,
0x7d,
0xec,
0x3a,
0xdc,
0x4d,
0x20,
0x79,
0xee,
0x5f,
0x3e,
0xd7,
0xcb,
0x39,
0x48
)
this.fk = new Array(0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc)
this.ck = new Array(
0x00070e15,
0x1c232a31,
0x383f464d,
0x545b6269,
0x70777e85,
0x8c939aa1,
0xa8afb6bd,
0xc4cbd2d9,
0xe0e7eef5,
0xfc030a11,
0x181f262d,
0x343b4249,
0x50575e65,
0x6c737a81,
0x888f969d,
0xa4abb2b9,
0xc0c7ced5,
0xdce3eaf1,
0xf8ff060d,
0x141b2229,
0x30373e45,
0x4c535a61,
0x686f767d,
0x848b9299,
0xa0a7aeb5,
0xb***3cad1,
0xd8dfe6ed,
0xf4fb0209,
0x10171e25,
0x2c333a41,
0x484f565d,
0x646b7279
)
}
SM4.prototype = {
expandKey: function (key) {
var k = new Array(36)
var mk = byteArrayToIntArray(key)
k[0] = mk[0] ^ this.fk[0]
k[1] = mk[1] ^ this.fk[1]
k[2] = mk[2] ^ this.fk[2]
k[3] = mk[3] ^ this.fk[3]
var rk = new Array(32)
for (var i = 0; i < 32; i++) {
k[i + 4] = k[i] ^ this.T1(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ this.ck[i])
rk[i] = k[i + 4]
}
return rk
},
T1: function (ta) {
var rk = 0
var b = new Array(4)
var a = intToByte(ta)
b[0] = this.sbox[a[0] & 0xff]
b[1] = this.sbox[a[1] & 0xff]
b[2] = this.sbox[a[2] & 0xff]
b[3] = this.sbox[a[3] & 0xff]
var bint = byteToInt(b, 0)
var rk = bint ^ ((bint << 13) | (bint >>> (32 - 13))) ^ ((bint << 23) | (bint >>> (32 - 23)))
return rk
},
one_encrypt: function (rk, data) {
var x = new Array(36)
x[0] = byteToInt(data, 0)
x[1] = byteToInt(data, 4)
x[2] = byteToInt(data, 8)
x[3] = byteToInt(data, 12)
for (var i = 0; i < 32; i++) {
x[i + 4] = x[i] ^ this.T0(x[i + 1] ^ x[i + 2] ^ x[i + 3] ^ rk[i])
}
var tmpx = new Array(4)
for (var i = 35; i >= 32; i--) {
tmpx[35 - i] = x[i]
}
var xbyte = intArrayToByteArray(tmpx)
return xbyte
},
T0: function (ta) {
var a = intToByte(ta)
var b = new Array(4)
b[0] = this.sbox[a[0] & 0xff]
b[1] = this.sbox[a[1] & 0xff]
b[2] = this.sbox[a[2] & 0xff]
b[3] = this.sbox[a[3] & 0xff]
var bint = byteToInt(b, 0)
var c =
bint ^
((bint << 2) | (bint >>> (32 - 2))) ^
((bint << 10) | (bint >>> (32 - 10))) ^
((bint << 18) | (bint >>> (32 - 18))) ^
((bint << 24) | (bint >>> (32 - 24)))
return c
},
pkcs7padding: function (input, mode) {
if (input == null) {
return null
}
var ret = null
if (mode == 1) {
//填充
var p = 16 - (input.length % 16)
ret = new Array(input.length + p)
arrayCopy(input, 0, ret, 0, input.length)
for (var i = 0; i < p; i++) {
ret[input.length + i] = p
}
} //去除填充
else {
var p = input[input.length - 1]
ret = new Array(input.length - p)
arrayCopy(input, 0, ret, 0, input.length - p)
}
return ret
},
/**
*
* @param key 字节数组
* @param data 字节数组
* @returns {any[]|null}
*/
encrypt_ecb: function (key, data) {
if (key == undefined || key == null || key.length % 16 != 0) {
console.log('sm4 key is error!')
return null
}
if (data == undefined || data == null || data.length <= 0) {
console.log('data is error!')
return null
}
var rk = this.expandKey(key)
/*if(debug){
var rkb = intArrayToByteArray(rk);
console.log(Hex.encode(rkb,0,rkb.length));
}*/
var blockLen = 16
var loop = parseInt(data.length / blockLen) //注意不能整除会有小数，要取整
var cipher = new Array((loop + 1) * blockLen)
var tmp = new Array(blockLen)
var oneCipher = null
for (var i = 0; i < loop; i++) {
arrayCopy(data, i * blockLen, tmp, 0, blockLen)
oneCipher = this.one_encrypt(rk, tmp)
arrayCopy(oneCipher, 0, cipher, i * blockLen, blockLen)
}
var lessData = new Array(data.length % blockLen)
if (lessData.length > 0) {
arrayCopy(data, loop * blockLen, lessData, 0, data.length % blockLen)
}
var padding = this.pkcs7padding(lessData, 1)
oneCipher = this.one_encrypt(rk, padding)
arrayCopy(oneCipher, 0, cipher, loop * blockLen, blockLen)
return cipher
},
/**
*
* @param key 字节数组
* @param data 字节数组
* @returns {any[]|null}
*/
decrypt_ecb: function (key, data) {
if (key == undefined || key == null || key.length % 16 != 0) {
console.log('sm4 key is error!')
return null
}
if (data == undefined || data == null || data.length % 16 != 0) {
console.log('data is error!')
return null
}
var rk = this.expandKey(key)
var nrk = new Array(32)
for (var i = 0; i < rk.length; i++) {
nrk[i] = rk[32 - i - 1]
}
var blockLen = 16
var loop = data.length / blockLen - 1
var tmp = new Array(blockLen)
var onePlain = null
var plain = null
//先解密最后一部分，确定数据长度
arrayCopy(data, loop * blockLen, tmp, 0, blockLen)
onePlain = this.one_encrypt(nrk, tmp)
var lastPart = this.pkcs7padding(onePlain, 0)
plain = new Array(loop * blockLen + lastPart.length)
arrayCopy(lastPart, 0, plain, loop * blockLen, lastPart.length)
//解密剩下部分数据
for (var i = 0; i < loop; i++) {
arrayCopy(data, i * blockLen, tmp, 0, blockLen)
onePlain = this.one_encrypt(nrk, tmp)
arrayCopy(onePlain, 0, plain, i * blockLen, blockLen)
}
return plain
},
encrypt_cbc: function (key, iv, data) {
if (key == undefined || key == null || key.length % 16 != 0) {
console.log('sm4 key is error!')
return null
}
if (data == undefined || data == null || data.length <= 0) {
console.log('data is error!')
return null
}
if (iv == undefined || iv == null || iv.length % 16 != 0) {
console.log('iv is error!')
return null
}
var rk = this.expandKey(key)
var blockLen = 16
var loop = parseInt(data.length / blockLen) //注意不能整除会有小数，要取整
var cipher = new Array((loop + 1) * blockLen)
var tmp = new Array(blockLen)
var oneCipher = null
for (var i = 0; i < loop; i++) {
arrayCopy(data, i * blockLen, tmp, 0, blockLen)
for (var j = 0; j < blockLen; j++) {
tmp[j] = tmp[j] ^ iv[j]
}
iv = this.one_encrypt(rk, tmp)
arrayCopy(iv, 0, cipher, i * blockLen, blockLen)
}
var lessData = new Array(data.length % blockLen)
if (lessData.length > 0) {
arrayCopy(data, loop * blockLen, lessData, 0, data.length % blockLen)
}
var padding = this.pkcs7padding(lessData, 1)
for (var i = 0; i < blockLen; i++) {
padding[i] = padding[i] ^ iv[i]
}
iv = this.one_encrypt(rk, padding)
arrayCopy(iv, 0, cipher, loop * blockLen, blockLen)
return cipher
},
decrypt_cbc: function (key, iv, data) {
if (key == undefined || key == null || key.length % 16 != 0) {
console.log('sm4 key is error!')
return null
}
if (data == undefined || data == null || data.length % 16 != 0) {
console.log('data is error!')
return null
}
if (iv == undefined || iv == null || iv.length % 16 != 0) {
console.log('iv is error!')
return null
}
var rk = this.expandKey(key)
var nrk = new Array(32)
for (var i = 0; i < rk.length; i++) {
nrk[i] = rk[32 - i - 1]
}
var blockLen = 16
var loop = data.length / blockLen
var tmp = new Array(blockLen)
var onePlain = null
var plain = null
//解密
plain = new Array(data.length)
for (var i = 0; i < loop; i++) {
arrayCopy(data, i * blockLen, tmp, 0, blockLen)
onePlain = this.one_encrypt(nrk, tmp)
for (var j = 0; j < blockLen; j++) {
onePlain[j] = onePlain[j] ^ iv[j]
}
arrayCopy(tmp, 0, iv, 0, blockLen)
arrayCopy(onePlain, 0, plain, i * blockLen, blockLen)
}
//去填充，确定数据长度
//arrayCopy(data,data.length-blockLen,tmp,0,blockLen);
var lastPart = this.pkcs7padding(onePlain, 0)
var realPlain = new Array(plain.length - blockLen + lastPart.length)
arrayCopy(plain, 0, realPlain, 0, plain.length - blockLen)
arrayCopy(lastPart, 0, realPlain, plain.length - blockLen, lastPart.length)
return realPlain
}
}
///工具类/
/*
* 数组复制
*/
function arrayCopy(src, pos1, dest, pos2, len) {
var realLen = len
if (pos1 + len > src.length && pos2 + len <= dest.length) {
realLen = src.length - pos1
} else if (pos2 + len > dest.length && pos1 + len <= src.length) {
realLen = dest.length - pos2
} else if (pos1 + len <= src.length && pos2 + len <= dest.length) {
realLen = len
} else if (dest.length < src.length) {
realLen = dest.length - pos2
} else {
realLen = src.length - pos2
}
for (var i = 0; i < realLen; i++) {
dest[i + pos2] = src[i + pos1]
}
}
/*
* 长整型转成字节，一个长整型为8字节
* 返回：字节数组
*/
function longToByte(num) {
//TODO 这里目前只转换了低四字节，因为js没有长整型，得要封装
return new Array(
0,
0,
0,
0,
(num >> 24) & 0x000000ff,
(num >> 16) & 0x000000ff,
(num >> 8) & 0x000000ff,
num & 0x000000ff
)
}
/*
* int数转成byte数组
* 事实上只不过转成byte大小的数，实际占用空间还是4字节
* 返回：字节数组
*/
function intToByte(num) {
return new Array((num >> 24) & 0x000000ff, (num >> 16) & 0x000000ff, (num >> 8) & 0x000000ff, num & 0x000000ff)
}
/*
* int数组转成byte数组，一个int数值转成四个byte
* 返回:byte数组
*/
function intArrayToByteArray(nums) {
var b = new Array(nums.length * 4)
for (var i = 0; i < nums.length; i++) {
arrayCopy(intToByte(nums[i]), 0, b, i * 4, 4)
}
return b
}
/*
* byte数组转成int数值
* 返回：int数值
*/
function byteToInt(b, pos) {
if (pos + 3 < b.length) {
return (b[pos] << 24) | (b[pos + 1] << 16) | (b[pos + 2] << 8) | b[pos + 3]
} else if (pos + 2 < b.length) {
return (b[pos + 1] << 16) | (b[pos + 2] << 8) | b[pos + 3]
} else if (pos + 1 < b.length) {
return (b[pos] << 8) | b[pos + 1]
} else {
return b[pos]
}
}
/*
* byte数组转成int数组,每四个字节转成一个int数值
*
*/
function byteArrayToIntArray(b) {
// var arrLen = b.length%4==0 ? b.length/4:b.length/4+1;
var arrLen = Math.ceil(b.length / 4) //向上取整
var out = new Array(arrLen)
for (var i = 0; i < b.length; i++) {
b[i] = b[i] & 0xff //避免负数造成影响
}
for (var i = 0; i < out.length; i++) {
out[i] = byteToInt(b, i * 4)
}
return out
}
module.exports = SM4
2. 使用 - ECB 模式加解密
import SM4Util from '@/utils/SM4Util'
const miStr = SM4Util.sm4ECBEncrypt('13012345678', '93F3044B07393417') // 加密 SM4Util.sm4ECBEncrypt(需要加密的字符串, 密钥)
console.log('miStr----', miStr) // 8O/HeW8uoXU/CkcDaXRpxQ==
const jieStr = SM4Util.sm4ECBDecrypt(miStr, '93F3044B07393417') // 解密 SM4Util.sm4ECBDecrypt(加密后的字符串, 密钥)
console.log('jieStr----', jieStr) // 13012345678
// 加密后传给后端进行解密
可能出现的报错
若出现该报错，即为解密失败，可能是加密出错导致 Uncaught RangeError: Invalid array length
