JS逆向之常见编码和混淆加密方式（一）
一般情况下，js的代码加密用来加密混淆代码，降低代码的可读性，如果一段没有经过任何加密混淆的代码，很容易被第三方或者脚本破解利用，引发许多的安全问题，本文将从以下多个角度讲解，代码加密的一些基本原理**（注意：本文不涉及JS代码的混淆性，只讲解一些基本的JS逆向所需要的代码加密方式）**。
JS加密方式：
- 1、对象属性的访问方式
- 2、十六进制字符串
- 3、unicode字符串
- 3、ASCLL码混淆
- 4、Base64加密
- 5、MD5加密
- 6、SHA1加密
- 7、数值常量加密
- **JS逆向 代码加密方式任重而道远，下一篇讲讲述AES对称加密、RSA非对称加密，整体替换，AAEncode加密和其他加密方式**
1、对象属性的访问方式
想混淆对象属性的访问方式其实很简单，在JS语法中，直接用.方法可以直接调用方法，也可以使用中括号+方法的形式去调用，中括号内传入一个字符串,这样就改变了对象属性的访问方式了，由于传入的是字符串，所以还可以进一步进行拼接+加密的方式去访问属性。这种方式后文也会讲到。
function Objects(name){
this.name = name
Objects.prototype.hello = function(){console.log("hello")}
}
var obj = new Objects("js")
obj.name //"js"
obj["name"] //"js"
obj.hello() // hello
obj["hello"]() // hello
2、十六进制字符串
上述方法讲述了，通过改变对象属性的方式，但即使是这样，代码的可读性仍然比较高，上述方法的字符串仍然可以进行混淆加密处理，字符串可以使用十六进制来表示.
function strtohex(code){
var hexstr = [];
for (i=0;i十六进制的还原方式也非常简单，在控制台直接输出十六进制字符串即可。
3、unicode字符串
除了支持十六进制字符串表示意外，还可以使用unicode字符串形式表示。
function unicode(str){
var value='';
for (var i = 0; i < str.length; i++) {
value += '\\u' + left_zero_4(parseInt(str.charCodeAt(i)).toString(16));
}
return value;
}
function left_zero_4(str) {
if (str != null && str != '' && str != 'undefined') {
if (str.length == 2) {
return '00' + str;
}
}
return str;
}
unicode("123456")
"\u0031\u0032\u0033\u0034\u0035\u0036"
unicode 还原方法
function reconvert(str){
str = str.replace(/(\\u)(\w{1,4})/gi,function($0){
return (String.fromCharCode(parseInt((escape($0).replace(/(%5Cu)(\w{1,4})/g,"$2")),16)));
});
str = str.replace(/(&#x)(\w{1,4});/gi,function($0){
return String.fromCharCode(parseInt(escape($0).replace(/(%26%23x)(\w{1,4})(%3B)/g,"$2"),16));
});
str = str.replace(/(&#)(\d{1,6});/gi,function($0){
return String.fromCharCode(parseInt(escape($0).replace(/(%26%23)(\d{1,6})(%3B)/g,"$2")));
});
return str;
}
reconvert("\u0031\u0032\u0033\u0034\u0035\u0036")
"123456"
3、ASCLL码混淆
ascll码利用了字符的ascll的转码和解码方式进行混淆，加密和解密方式也非常简单
function strtoascll(code){
for (i=0;i还原ascll码的话使用String.fromcharcode方法。
String.fromCharCode(49,50,51,52,53,54)
"123456"
4、Base64加密
Base64加密一般都是用于字符串常量加密，在使用前，先把字符串进行加密，一般也多用于一些属性的访问方式,浏览器有自带的Base64编码和解码的函数，atob用来解码，btoa用来编码，把编码后的字符串放入代码中，也需要把解码函数放入才能执行代码
btoa("123")
"MTIz"
atob("MTIz")
"123"
通过这种方式，结合第一小节讲的通过中括号+方法名的方式访问对象属性，可以进一步的进行加密，例如：
function Objects(name){
this.name = name
Objects.prototype.hello = function(){console.log("hello")}
}
var obj = new Objects("js")
obj[atob("bmFtZQ==")] //"js"
obj[atob("aGVsbG8=")]() // hello
5、MD5加密
MD5信息摘要算法，一种被广泛使用的密码散列函数，可以产生出一个128位（16字节）的散列值（hash value），用于确保信息传输完整一致。需要注意的是，MD5加密算法是不可逆的，解密一般都是通过网站的接口.
首先看一下md5的大致加密方式。
/*
* A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
* Digest Algorithm, as defined in RFC 1321.
* Version 2.1 Copyright (C) Paul Johnston 1999 - 2002.
* Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
* Distributed under the BSD License
* See http://pajhome.org.uk/crypt/md5 for more info.
*/
/*
* Configurable variables. You may need to tweak these to be compatible with
* the server-side, but the defaults work in most cases.
*/
var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */
var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */
var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode */
/*
* These are the functions you'll usually want to call
* They take string arguments and return either hex or base-64 encoded strings
*/
function hex_md5(s){ return binl2hex(core_md5(str2binl(s), s.length * chrsz));}
function b64_md5(s){ return binl2b64(core_md5(str2binl(s), s.length * chrsz));}
function str_md5(s){ return binl2str(core_md5(str2binl(s), s.length * chrsz));}
function hex_hmac_md5(key, data) { return binl2hex(core_hmac_md5(key, data)); }
function b64_hmac_md5(key, data) { return binl2b64(core_hmac_md5(key, data)); }
function str_hmac_md5(key, data) { return binl2str(core_hmac_md5(key, data)); }
/*
* Perform a simple self-test to see if the VM is working
*/
function md5_vm_test()
{
return hex_md5("abc") == "900150983cd24fb0d6963f7d28e17f72";
}
/*
* Calculate the MD5 of an array of little-endian words, and a bit length
*/
function core_md5(x, len)
{
/* append padding */
x[len >> 5] |= 0x80 << ((len) % 32);
x[(((len + 64) >>> 9) << 4) + 14] = len;
var a = 1732584193;
var b = -271733879;
var c = -1732584194;
var d = 271733878;
for(var i = 0; i < x.length; i += 16)
{
var olda = a;
var oldb = b;
var oldc = c;
var oldd = d;
a = md5_ff(a, b, c, d, x[i+ 0], 7 , -680876936);
d = md5_ff(d, a, b, c, x[i+ 1], 12, -389564586);
c = md5_ff(c, d, a, b, x[i+ 2], 17, 606105819);
b = md5_ff(b, c, d, a, x[i+ 3], 22, -1044525330);
a = md5_ff(a, b, c, d, x[i+ 4], 7 , -176418897);
d = md5_ff(d, a, b, c, x[i+ 5], 12, 1200080426);
c = md5_ff(c, d, a, b, x[i+ 6], 17, -1473231341);
b = md5_ff(b, c, d, a, x[i+ 7], 22, -45705983);
a = md5_ff(a, b, c, d, x[i+ 8], 7 , 1770035416);
d = md5_ff(d, a, b, c, x[i+ 9], 12, -1958414417);
c = md5_ff(c, d, a, b, x[i+10], 17, -42063);
b = md5_ff(b, c, d, a, x[i+11], 22, -1990404162);
a = md5_ff(a, b, c, d, x[i+12], 7 , 1804603682);
d = md5_ff(d, a, b, c, x[i+13], 12, -40341101);
c = md5_ff(c, d, a, b, x[i+14], 17, -1502002290);
b = md5_ff(b, c, d, a, x[i+15], 22, 1236535329);
a = md5_gg(a, b, c, d, x[i+ 1], 5 , -165796510);
d = md5_gg(d, a, b, c, x[i+ 6], 9 , -1069501632);
c = md5_gg(c, d, a, b, x[i+11], 14, 643717713);
b = md5_gg(b, c, d, a, x[i+ 0], 20, -373897302);
a = md5_gg(a, b, c, d, x[i+ 5], 5 , -701558691);
d = md5_gg(d, a, b, c, x[i+10], 9 , 38016083);
c = md5_gg(c, d, a, b, x[i+15], 14, -660478335);
b = md5_gg(b, c, d, a, x[i+ 4], 20, -405537848);
a = md5_gg(a, b, c, d, x[i+ 9], 5 , 568446438);
d = md5_gg(d, a, b, c, x[i+14], 9 , -1019803690);
c = md5_gg(c, d, a, b, x[i+ 3], 14, -187363961);
b = md5_gg(b, c, d, a, x[i+ 8], 20, 1163531501);
a = md5_gg(a, b, c, d, x[i+13], 5 , -1444681467);
d = md5_gg(d, a, b, c, x[i+ 2], 9 , -51403784);
c = md5_gg(c, d, a, b, x[i+ 7], 14, 1735328473);
b = md5_gg(b, c, d, a, x[i+12], 20, -1926607734);
a = md5_hh(a, b, c, d, x[i+ 5], 4 , -378558);
d = md5_hh(d, a, b, c, x[i+ 8], 11, -2022574463);
c = md5_hh(c, d, a, b, x[i+11], 16, 1839030562);
b = md5_hh(b, c, d, a, x[i+14], 23, -35309556);
a = md5_hh(a, b, c, d, x[i+ 1], 4 , -1530992060);
d = md5_hh(d, a, b, c, x[i+ 4], 11, 1272893353);
c = md5_hh(c, d, a, b, x[i+ 7], 16, -155497632);
b = md5_hh(b, c, d, a, x[i+10], 23, -1094730640);
a = md5_hh(a, b, c, d, x[i+13], 4 , 681279174);
d = md5_hh(d, a, b, c, x[i+ 0], 11, -358537222);
c = md5_hh(c, d, a, b, x[i+ 3], 16, -722521979);
b = md5_hh(b, c, d, a, x[i+ 6], 23, 76029189);
a = md5_hh(a, b, c, d, x[i+ 9], 4 , -640364487);
d = md5_hh(d, a, b, c, x[i+12], 11, -421815835);
c = md5_hh(c, d, a, b, x[i+15], 16, 530742520);
b = md5_hh(b, c, d, a, x[i+ 2], 23, -995338651);
a = md5_ii(a, b, c, d, x[i+ 0], 6 , -198630844);
d = md5_ii(d, a, b, c, x[i+ 7], 10, 1126891415);
c = md5_ii(c, d, a, b, x[i+14], 15, -1416354905);
b = md5_ii(b, c, d, a, x[i+ 5], 21, -57434055);
a = md5_ii(a, b, c, d, x[i+12], 6 , 1700485571);
d = md5_ii(d, a, b, c, x[i+ 3], 10, -1894986606);
c = md5_ii(c, d, a, b, x[i+10], 15, -1051523);
b = md5_ii(b, c, d, a, x[i+ 1], 21, -2054922799);
a = md5_ii(a, b, c, d, x[i+ 8], 6 , 1873313359);
d = md5_ii(d, a, b, c, x[i+15], 10, -30611744);
c = md5_ii(c, d, a, b, x[i+ 6], 15, -1560198380);
b = md5_ii(b, c, d, a, x[i+13], 21, 1309151649);
a = md5_ii(a, b, c, d, x[i+ 4], 6 , -145523070);
d = md5_ii(d, a, b, c, x[i+11], 10, -1120210379);
c = md5_ii(c, d, a, b, x[i+ 2], 15, 718787259);
b = md5_ii(b, c, d, a, x[i+ 9], 21, -343485551);
a = safe_add(a, olda);
b = safe_add(b, oldb);
c = safe_add(c, oldc);
d = safe_add(d, oldd);
}
return Array(a, b, c, d);
}
/*
* These functions implement the four basic operations the algorithm uses.
*/
function md5_cmn(q, a, b, x, s, t)
{
return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s),b);
}
function md5_ff(a, b, c, d, x, s, t)
{
return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);
}
function md5_gg(a, b, c, d, x, s, t)
{
return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);
}
function md5_hh(a, b, c, d, x, s, t)
{
return md5_cmn(b ^ c ^ d, a, b, x, s, t);
}
function md5_ii(a, b, c, d, x, s, t)
{
return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);
}
/*
* Calculate the HMAC-MD5, of a key and some data
*/
function core_hmac_md5(key, data)
{
var bkey = str2binl(key);
if(bkey.length > 16) bkey = core_md5(bkey, key.length * chrsz);
var ipad = Array(16), opad = Array(16);
for(var i = 0; i < 16; i++)
{
ipad[i] = bkey[i] ^ 0x36363636;
opad[i] = bkey[i] ^ 0x5C5C5C5C;
}
var hash = core_md5(ipad.concat(str2binl(data)), 512 + data.length * chrsz);
return core_md5(opad.concat(hash), 512 + 128);
}
/*
* Add integers, wrapping at 2^32. This uses 16-bit operations internally
* to work around bugs in some JS interpreters.
*/
function safe_add(x, y)
{
var lsw = (x & 0xFFFF) + (y & 0xFFFF);
var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
}
/*
* Bitwise rotate a 32-bit number to the left.
*/
function bit_rol(num, cnt)
{
return (num << cnt) | (num >>> (32 - cnt));
}
/*
* Convert a string to an array of little-endian words
* If chrsz is ASCII, characters >255 have their hi-byte silently ignored.
*/
function str2binl(str)
{
var bin = Array();
var mask = (1 << chrsz) - 1;
for(var i = 0; i < str.length * chrsz; i += chrsz)
bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (i%32);
return bin;
}
/*
* Convert an array of little-endian words to a string
*/
function binl2str(bin)
{
var str = "";
var mask = (1 << chrsz) - 1;
for(var i = 0; i < bin.length * 32; i += chrsz)
str += String.fromCharCode((bin[i>>5] >>> (i % 32)) & mask);
return str;
}
/*
* Convert an array of little-endian words to a hex string.
*/
function binl2hex(binarray)
{
var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
var str = "";
for(var i = 0; i < binarray.length * 4; i++)
{
str += hex_tab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF) +
hex_tab.charAt((binarray[i>>2] >> ((i%4)*8 )) & 0xF);
}
return str;
}
/*
* Convert an array of little-endian words to a base-64 string
*/
function binl2b64(binarray)
{
var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var str = "";
for(var i = 0; i < binarray.length * 4; i += 3)
{
var triplet = (((binarray[i >> 2] >> 8 * ( i %4)) & 0xFF) << 16)
| (((binarray[i+1 >> 2] >> 8 * ((i+1)%4)) & 0xFF) << 8 )
| ((binarray[i+2 >> 2] >> 8 * ((i+2)%4)) & 0xFF);
for(var j = 0; j < 4; j++)
{
if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
}
}
return str;
}
执行完这段代码后，就可以执行加密了
hex_md5("123456");
"e10adc3949ba59abbe56e057f20f883e"
一般来说，这样加密后的字符串会传入后台去比对，由于MD5不可逆，所以加密后的字符串是无法解密的
6、SHA1加密
SHA-1（中文名：安全散列算法1）是一种密码散列函数，美国国家安全局设计，并由美国国家标准技术研究所（NIST）发布为联邦数据处理标准（FIPS）。sha1相比MD5，SHA1所产生的摘要比MD5长32位,安全性更高，一般没有经过高度混淆的JS，sha1加密的关键词就是sha1，下面是sha1加密的源码，sha1同样也是不可逆的
/*
* [js-sha1]{@link https://github.com/emn178/js-sha1}
*
* @version 0.6.0
* @author Chen, Yi-Cyuan [[email protected]]
* @copyright Chen, Yi-Cyuan 2014-2017
* @license MIT
*/
/*jslint bitwise: true */
(function() {
'use strict';
var root = typeof window === 'object' ? window : {};
var NODE_JS = !root.JS_SHA1_NO_NODE_JS && typeof process === 'object' && process.versions && process.versions.node;
if (NODE_JS) {
root = global;
}
var COMMON_JS = !root.JS_SHA1_NO_COMMON_JS && typeof module === 'object' && module.exports;
var AMD = typeof define === 'function' && define.amd;
var HEX_CHARS = '0123456789abcdef'.split('');
var EXTRA = [-2147483648, 8388608, 32768, 128];
var SHIFT = [24, 16, 8, 0];
var OUTPUT_TYPES = ['hex', 'array', 'digest', 'arrayBuffer'];
var blocks = [];
var createOutputMethod = function (outputType) {
return function (message) {
return new Sha1(true).update(message)[outputType]();
};
};
var createMethod = function () {
var method = createOutputMethod('hex');
if (NODE_JS) {
method = nodeWrap(method);
}
method.create = function () {
return new Sha1();
};
method.update = function (message) {
return method.create().update(message);
};
for (var i = 0; i < OUTPUT_TYPES.length; ++i) {
var type = OUTPUT_TYPES[i];
method[type] = createOutputMethod(type);
}
return method;
};
var nodeWrap = function (method) {
var crypto = eval("require('crypto')");
var Buffer = eval("require('buffer').Buffer");
var nodeMethod = function (message) {
if (typeof message === 'string') {
return crypto.createHash('sha1').update(message, 'utf8').digest('hex');
} else if (message.constructor === ArrayBuffer) {
message = new Uint8Array(message);
} else if (message.length === undefined) {
return method(message);
}
return crypto.createHash('sha1').update(new Buffer(message)).digest('hex');
};
return nodeMethod;
};
function Sha1(sharedMemory) {
if (sharedMemory) {
blocks[0] = blocks[16] = blocks[1] = blocks[2] = blocks[3] =
blocks[4] = blocks[5] = blocks[6] = blocks[7] =
blocks[8] = blocks[9] = blocks[10] = blocks[11] =
blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0;
this.blocks = blocks;
} else {
this.blocks = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
}
this.h0 = 0x67452301;
this.h1 = 0xEFCDAB89;
this.h2 = 0x98BADCFE;
this.h3 = 0x10325476;
this.h4 = 0xC3D2E1F0;
this.block = this.start = this.bytes = this.hBytes = 0;
this.finalized = this.hashed = false;
this.first = true;
}
Sha1.prototype.update = function (message) {
if (this.finalized) {
return;
}
var notString = typeof(message) !== 'string';
if (notString && message.constructor === root.ArrayBuffer) {
message = new Uint8Array(message);
}
var code, index = 0, i, length = message.length || 0, blocks = this.blocks;
while (index < length) {
if (this.hashed) {
this.hashed = false;
blocks[0] = this.block;
blocks[16] = blocks[1] = blocks[2] = blocks[3] =
blocks[4] = blocks[5] = blocks[6] = blocks[7] =
blocks[8] = blocks[9] = blocks[10] = blocks[11] =
blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0;
}
if(notString) {
for (i = this.start; index < length && i < 64; ++index) {
blocks[i >> 2] |= message[index] << SHIFT[i++ & 3];
}
} else {
for (i = this.start; index < length && i < 64; ++index) {
code = message.charCodeAt(index);
if (code < 0x80) {
blocks[i >> 2] |= code << SHIFT[i++ & 3];
} else if (code < 0x800) {
blocks[i >> 2] |= (0xc0 | (code >> 6)) << SHIFT[i++ & 3];
blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3];
} else if (code < 0xd800 || code >= 0xe000) {
blocks[i >> 2] |= (0xe0 | (code >> 12)) << SHIFT[i++ & 3];
blocks[i >> 2] |= (0x80 | ((code >> 6) & 0x3f)) << SHIFT[i++ & 3];
blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3];
} else {
code = 0x10000 + (((code & 0x3ff) << 10) | (message.charCodeAt(++index) & 0x3ff));
blocks[i >> 2] |= (0xf0 | (code >> 18)) << SHIFT[i++ & 3];
blocks[i >> 2] |= (0x80 | ((code >> 12) & 0x3f)) << SHIFT[i++ & 3];
blocks[i >> 2] |= (0x80 | ((code >> 6) & 0x3f)) << SHIFT[i++ & 3];
blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3];
}
}
}
this.lastByteIndex = i;
this.bytes += i - this.start;
if (i >= 64) {
this.block = blocks[16];
this.start = i - 64;
this.hash();
this.hashed = true;
} else {
this.start = i;
}
}
if (this.bytes > 4294967295) {
this.hBytes += this.bytes / 4294967296 << 0;
this.bytes = this.bytes % 4294967296;
}
return this;
};
Sha1.prototype.finalize = function () {
if (this.finalized) {
return;
}
this.finalized = true;
var blocks = this.blocks, i = this.lastByteIndex;
blocks[16] = this.block;
blocks[i >> 2] |= EXTRA[i & 3];
this.block = blocks[16];
if (i >= 56) {
if (!this.hashed) {
this.hash();
}
blocks[0] = this.block;
blocks[16] = blocks[1] = blocks[2] = blocks[3] =
blocks[4] = blocks[5] = blocks[6] = blocks[7] =
blocks[8] = blocks[9] = blocks[10] = blocks[11] =
blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0;
}
blocks[14] = this.hBytes << 3 | this.bytes >>> 29;
blocks[15] = this.bytes << 3;
this.hash();
};
Sha1.prototype.hash = function () {
var a = this.h0, b = this.h1, c = this.h2, d = this.h3, e = this.h4;
var f, j, t, blocks = this.blocks;
for(j = 16; j < 80; ++j) {
t = blocks[j - 3] ^ blocks[j - 8] ^ blocks[j - 14] ^ blocks[j - 16];
blocks[j] = (t << 1) | (t >>> 31);
}
for(j = 0; j < 20; j += 5) {
f = (b & c) | ((~b) & d);
t = (a << 5) | (a >>> 27);
e = t + f + e + 1518500249 + blocks[j] << 0;
b = (b << 30) | (b >>> 2);
f = (a & b) | ((~a) & c);
t = (e << 5) | (e >>> 27);
d = t + f + d + 1518500249 + blocks[j + 1] << 0;
a = (a << 30) | (a >>> 2);
f = (e & a) | ((~e) & b);
t = (d << 5) | (d >>> 27);
c = t + f + c + 1518500249 + blocks[j + 2] << 0;
e = (e << 30) | (e >>> 2);
f = (d & e) | ((~d) & a);
t = (c << 5) | (c >>> 27);
b = t + f + b + 1518500249 + blocks[j + 3] << 0;
d = (d << 30) | (d >>> 2);
f = (c & d) | ((~c) & e);
t = (b << 5) | (b >>> 27);
a = t + f + a + 1518500249 + blocks[j + 4] << 0;
c = (c << 30) | (c >>> 2);
}
for(; j < 40; j += 5) {
f = b ^ c ^ d;
t = (a << 5) | (a >>> 27);
e = t + f + e + 1859775393 + blocks[j] << 0;
b = (b << 30) | (b >>> 2);
f = a ^ b ^ c;
t = (e << 5) | (e >>> 27);
d = t + f + d + 1859775393 + blocks[j + 1] << 0;
a = (a << 30) | (a >>> 2);
f = e ^ a ^ b;
t = (d << 5) | (d >>> 27);
c = t + f + c + 1859775393 + blocks[j + 2] << 0;
e = (e << 30) | (e >>> 2);
f = d ^ e ^ a;
t = (c << 5) | (c >>> 27);
b = t + f + b + 1859775393 + blocks[j + 3] << 0;
d = (d << 30) | (d >>> 2);
f = c ^ d ^ e;
t = (b << 5) | (b >>> 27);
a = t + f + a + 1859775393 + blocks[j + 4] << 0;
c = (c << 30) | (c >>> 2);
}
for(; j < 60; j += 5) {
f = (b & c) | (b & d) | (c & d);
t = (a << 5) | (a >>> 27);
e = t + f + e - 1894007588 + blocks[j] << 0;
b = (b << 30) | (b >>> 2);
f = (a & b) | (a & c) | (b & c);
t = (e << 5) | (e >>> 27);
d = t + f + d - 1894007588 + blocks[j + 1] << 0;
a = (a << 30) | (a >>> 2);
f = (e & a) | (e & b) | (a & b);
t = (d << 5) | (d >>> 27);
c = t + f + c - 1894007588 + blocks[j + 2] << 0;
e = (e << 30) | (e >>> 2);
f = (d & e) | (d & a) | (e & a);
t = (c << 5) | (c >>> 27);
b = t + f + b - 1894007588 + blocks[j + 3] << 0;
d = (d << 30) | (d >>> 2);
f = (c & d) | (c & e) | (d & e);
t = (b << 5) | (b >>> 27);
a = t + f + a - 1894007588 + blocks[j + 4] << 0;
c = (c << 30) | (c >>> 2);
}
for(; j < 80; j += 5) {
f = b ^ c ^ d;
t = (a << 5) | (a >>> 27);
e = t + f + e - 899497514 + blocks[j] << 0;
b = (b << 30) | (b >>> 2);
f = a ^ b ^ c;
t = (e << 5) | (e >>> 27);
d = t + f + d - 899497514 + blocks[j + 1] << 0;
a = (a << 30) | (a >>> 2);
f = e ^ a ^ b;
t = (d << 5) | (d >>> 27);
c = t + f + c - 899497514 + blocks[j + 2] << 0;
e = (e << 30) | (e >>> 2);
f = d ^ e ^ a;
t = (c << 5) | (c >>> 27);
b = t + f + b - 899497514 + blocks[j + 3] << 0;
d = (d << 30) | (d >>> 2);
f = c ^ d ^ e;
t = (b << 5) | (b >>> 27);
a = t + f + a - 899497514 + blocks[j + 4] << 0;
c = (c << 30) | (c >>> 2);
}
this.h0 = this.h0 + a << 0;
this.h1 = this.h1 + b << 0;
this.h2 = this.h2 + c << 0;
this.h3 = this.h3 + d << 0;
this.h4 = this.h4 + e << 0;
};
Sha1.prototype.hex = function () {
this.finalize();
var h0 = this.h0, h1 = this.h1, h2 = this.h2, h3 = this.h3, h4 = this.h4;
return HEX_CHARS[(h0 >> 28) & 0x0F] + HEX_CHARS[(h0 >> 24) & 0x0F] +
HEX_CHARS[(h0 >> 20) & 0x0F] + HEX_CHARS[(h0 >> 16) & 0x0F] +
HEX_CHARS[(h0 >> 12) & 0x0F] + HEX_CHARS[(h0 >> 8) & 0x0F] +
HEX_CHARS[(h0 >> 4) & 0x0F] + HEX_CHARS[h0 & 0x0F] +
HEX_CHARS[(h1 >> 28) & 0x0F] + HEX_CHARS[(h1 >> 24) & 0x0F] +
HEX_CHARS[(h1 >> 20) & 0x0F] + HEX_CHARS[(h1 >> 16) & 0x0F] +
HEX_CHARS[(h1 >> 12) & 0x0F] + HEX_CHARS[(h1 >> 8) & 0x0F] +
HEX_CHARS[(h1 >> 4) & 0x0F] + HEX_CHARS[h1 & 0x0F] +
HEX_CHARS[(h2 >> 28) & 0x0F] + HEX_CHARS[(h2 >> 24) & 0x0F] +
HEX_CHARS[(h2 >> 20) & 0x0F] + HEX_CHARS[(h2 >> 16) & 0x0F] +
HEX_CHARS[(h2 >> 12) & 0x0F] + HEX_CHARS[(h2 >> 8) & 0x0F] +
HEX_CHARS[(h2 >> 4) & 0x0F] + HEX_CHARS[h2 & 0x0F] +
HEX_CHARS[(h3 >> 28) & 0x0F] + HEX_CHARS[(h3 >> 24) & 0x0F] +
HEX_CHARS[(h3 >> 20) & 0x0F] + HEX_CHARS[(h3 >> 16) & 0x0F] +
HEX_CHARS[(h3 >> 12) & 0x0F] + HEX_CHARS[(h3 >> 8) & 0x0F] +
HEX_CHARS[(h3 >> 4) & 0x0F] + HEX_CHARS[h3 & 0x0F] +
HEX_CHARS[(h4 >> 28) & 0x0F] + HEX_CHARS[(h4 >> 24) & 0x0F] +
HEX_CHARS[(h4 >> 20) & 0x0F] + HEX_CHARS[(h4 >> 16) & 0x0F] +
HEX_CHARS[(h4 >> 12) & 0x0F] + HEX_CHARS[(h4 >> 8) & 0x0F] +
HEX_CHARS[(h4 >> 4) & 0x0F] + HEX_CHARS[h4 & 0x0F];
};
Sha1.prototype.toString = Sha1.prototype.hex;
Sha1.prototype.digest = function () {
this.finalize();
var h0 = this.h0, h1 = this.h1, h2 = this.h2, h3 = this.h3, h4 = this.h4;
return [
(h0 >> 24) & 0xFF, (h0 >> 16) & 0xFF, (h0 >> 8) & 0xFF, h0 & 0xFF,
(h1 >> 24) & 0xFF, (h1 >> 16) & 0xFF, (h1 >> 8) & 0xFF, h1 & 0xFF,
(h2 >> 24) & 0xFF, (h2 >> 16) & 0xFF, (h2 >> 8) & 0xFF, h2 & 0xFF,
(h3 >> 24) & 0xFF, (h3 >> 16) & 0xFF, (h3 >> 8) & 0xFF, h3 & 0xFF,
(h4 >> 24) & 0xFF, (h4 >> 16) & 0xFF, (h4 >> 8) & 0xFF, h4 & 0xFF
];
};
Sha1.prototype.array = Sha1.prototype.digest;
Sha1.prototype.arrayBuffer = function () {
this.finalize();
var buffer = new ArrayBuffer(20);
var dataView = new DataView(buffer);
dataView.setUint32(0, this.h0);
dataView.setUint32(4, this.h1);
dataView.setUint32(8, this.h2);
dataView.setUint32(12, this.h3);
dataView.setUint32(16, this.h4);
return buffer;
};
var exports = createMethod();
if (COMMON_JS) {
module.exports = exports;
} else {
root.sha1 = exports;
if (AMD) {
define(function () {
return exports;
});
}
}
})();
执行完代码后，直接运行sha1加密代码
sha1("123456")
"7c4a8d09ca3762af61e59520943dc26494f8941b"
7、数值常量加密
算法加密过程中，也会使用到数值，可以看到，以上算法中，在算法的加密过程中，也会用到一些数值常量，通常我们也会使用搜索常量的方式来确定是哪种加密方式，不过，这种常量也可以进行加密混淆，他可以写成任意进制类型，也可以使用其他的简单加密，可以使用位异或的特性来加密，如果 a ^ b = c 那么， c ^ b = a, 用这种方式，可以取代加密算法中的常量。下面是一个简单的例子
1 ^ 2 = 3 // 3
1 = 3 ^ 2 # 这里的常量1 就可以用 3 ^ 2的方式来替代
除开上面的异或，也可能使用多种混淆方式结合使用。
JS逆向 代码加密方式任重而道远，下一篇讲讲述AES对称加密、RSA非对称加密，整体替换，AAEncode加密和其他加密方式
