js MD5加密处理

关于MD5：

MD5.js是通过前台js加密的方式对用户信息，密码等私密信息进行加密处理的工具，也可称为插件。

在本案例中 可以看到MD5共有6种加密方法：

1，  hex_md5(value)

2，  b64_md5(value)

3，  str_md5(value)

4，  hex_hmac_md5(key, data)

5，  b64_hmac_md5(key, data)

6，  str_hmac_md5(key, data)

下载地址：  点击下载

MD5.js 源代码如下 (若不想下载，可直接复制使用)：

 /*
  * 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;
 }

MD5加密优缺点：

1，用js对私密信息加密可避免在网络中输入明文信息，被他人截取数据包而造成数据泄露。

2，避免缓存中自动缓存密码。比如在使用火狐浏览器登陆时，输入的用户名及密码自动缓存后，下次登陆无需输入密码就可实现登录，这样就给别人留下了漏洞，当别人使用你的电脑登陆那么你的密码就泄露了。使用js加密时，缓存的加密后的密文，用密文做密码登录是不成功的，即使泄露也是泄露的密文，对密码不会造成威胁。  缺点是： 每次登陆时都要手动输入密码，比较麻烦。

3，使用js加密，减少了服务器加密时的资源消耗，从理论上提高了服务器的性能。为了安全，很有必要在做服务端的加密，无论从理论还是实际，两道门比一道门要安全些，至少给攻击者造成了一个障碍。

使用详情：

    <script src="js/md5.js"></script>
    <script>
        var code = "123456";
        var username = "123456";
        var password = "123456";
        var str1 = hex_md5("123456");
        var str2 = b64_md5("123456");
        var str3 = str_md5("123456");
        var str4 = hex_hmac_md5(code,code);
        var str5 = b64_hmac_md5(username,username);
        var str6 = str_hmac_md5(password,password);
        console.log(str1);            // e10adc3949ba59abbe56e057f20f883e
        console.log(str2);            // 4QrcOUm6Wau+VuBX8g+IPg
        console.log(str3);            // áÜ9IºY«¾VàWòˆ>
        console.log(str4);            // 30ce71a73bdd908c3955a90e8f7429ef
        console.log(str5);            // MM5xpzvdkIw5VakOj3Qp7w
        console.log(str6);            // 0Îq§;ݐŒ9U©t)ï
    </script>