//   ---------------------------
//   Sting.prototype.md5();
//   return a based md5 crypted string
//   Based on Javascript implementation
//   of MD5:
//   http://pajhome.org.uk/crypt/md5/index.html
//
//   A JavaScript implementation of the RSA Data Security,
//   Digest Algorithm, as defined in RFC 1321.
//   Version 1.1 Copyright (C) Paul Johnston 1999 - 2002.
//   Code also contributed by Greg Holt
//   See http://pajhome.org.uk/site/legal.html for details.
//   ---------------------------
String.prototype.md5 = function()
{
   function safe_add(x, y)
   {
      var lsw = (x & 0xFFFF) + (y & 0xFFFF);
      var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
      return (msw << 16) | (lsw & 0xFFFF);
   }
   function rol(num, cnt)
   {
      return (num << cnt) | (num >>> (32 - cnt));
   }
   function cmn(q, a, b, x, s, t)
   {
      return safe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
   }
   function ff(a, b, c, d, x, s, t)
   {
      return cmn((b & c) | ((~b) & d), a, b, x, s, t);
   }
   function gg(a, b, c, d, x, s, t)
   {
      return cmn((b & d) | (c & (~d)), a, b, x, s, t);
   }
   function hh(a, b, c, d, x, s, t)
   {
      return cmn(b ^ c ^ d, a, b, x, s, t);
   }
   function ii(a, b, c, d, x, s, t)
   {
      return cmn(c ^ (b | (~d)), a, b, x, s, t);
   }
   function coreMD5(x)
   {
      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 = ff(a, b, c, d, x[i + 0], 7, -680876936);
         d = ff(d, a, b, c, x[i + 1], 12, -389564586);
         c = ff(c, d, a, b, x[i + 2], 17, 606105819);
         b = ff(b, c, d, a, x[i + 3], 22, -1044525330);
         a = ff(a, b, c, d, x[i + 4], 7, -176418897);
         d = ff(d, a, b, c, x[i + 5], 12, 1200080426);
         c = ff(c, d, a, b, x[i + 6], 17, -1473231341);
         b = ff(b, c, d, a, x[i + 7], 22, -45705983);
         a = ff(a, b, c, d, x[i + 8], 7, 1770035416);
         d = ff(d, a, b, c, x[i + 9], 12, -1958414417);
         c = ff(c, d, a, b, x[i + 10], 17, -42063);
         b = ff(b, c, d, a, x[i + 11], 22, -1990404162);
         a = ff(a, b, c, d, x[i + 12], 7, 1804603682);
         d = ff(d, a, b, c, x[i + 13], 12, -40341101);
         c = ff(c, d, a, b, x[i + 14], 17, -1502002290);
         b = ff(b, c, d, a, x[i + 15], 22, 1236535329);
         a = gg(a, b, c, d, x[i + 1], 5, -165796510);
         d = gg(d, a, b, c, x[i + 6], 9, -1069501632);
         c = gg(c, d, a, b, x[i + 11], 14, 643717713);
         b = gg(b, c, d, a, x[i + 0], 20, -373897302);
         a = gg(a, b, c, d, x[i + 5], 5, -701558691);
         d = gg(d, a, b, c, x[i + 10], 9, 38016083);
         c = gg(c, d, a, b, x[i + 15], 14, -660478335);
         b = gg(b, c, d, a, x[i + 4], 20, -405537848);
         a = gg(a, b, c, d, x[i + 9], 5, 568446438);
         d = gg(d, a, b, c, x[i + 14], 9, -1019803690);
         c = gg(c, d, a, b, x[i + 3], 14, -187363961);
         b = gg(b, c, d, a, x[i + 8], 20, 1163531501);
         a = gg(a, b, c, d, x[i + 13], 5, -1444681467);
         d = gg(d, a, b, c, x[i + 2], 9, -51403784);
         c = gg(c, d, a, b, x[i + 7], 14, 1735328473);
         b = gg(b, c, d, a, x[i + 12], 20, -1926607734);
         a = hh(a, b, c, d, x[i + 5], 4, -378558);
         d = hh(d, a, b, c, x[i + 8], 11, -2022574463);
         c = hh(c, d, a, b, x[i + 11], 16, 1839030562);
         b = hh(b, c, d, a, x[i + 14], 23, -35309556);
         a = hh(a, b, c, d, x[i + 1], 4, -1530992060);
         d = hh(d, a, b, c, x[i + 4], 11, 1272893353);
         c = hh(c, d, a, b, x[i + 7], 16, -155497632);
         b = hh(b, c, d, a, x[i + 10], 23, -1094730640);
         a = hh(a, b, c, d, x[i + 13], 4, 681279174);
         d = hh(d, a, b, c, x[i + 0], 11, -358537222);
         c = hh(c, d, a, b, x[i + 3], 16, -722521979);
         b = hh(b, c, d, a, x[i + 6], 23, 76029189);
         a = hh(a, b, c, d, x[i + 9], 4, -640364487);
         d = hh(d, a, b, c, x[i + 12], 11, -421815835);
         c = hh(c, d, a, b, x[i + 15], 16, 530742520);
         b = hh(b, c, d, a, x[i + 2], 23, -995338651);
         a = ii(a, b, c, d, x[i + 0], 6, -198630844);
         d = ii(d, a, b, c, x[i + 7], 10, 1126891415);
         c = ii(c, d, a, b, x[i + 14], 15, -1416354905);
         b = ii(b, c, d, a, x[i + 5], 21, -57434055);
         a = ii(a, b, c, d, x[i + 12], 6, 1700485571);
         d = ii(d, a, b, c, x[i + 3], 10, -1894986606);
         c = ii(c, d, a, b, x[i + 10], 15, -1051523);
         b = ii(b, c, d, a, x[i + 1], 21, -2054922799);
         a = ii(a, b, c, d, x[i + 8], 6, 1873313359);
         d = ii(d, a, b, c, x[i + 15], 10, -30611744);
         c = ii(c, d, a, b, x[i + 6], 15, -1560198380);
         b = ii(b, c, d, a, x[i + 13], 21, 1309151649);
         a = ii(a, b, c, d, x[i + 4], 6, -145523070);
         d = ii(d, a, b, c, x[i + 11], 10, -1120210379);
         c = ii(c, d, a, b, x[i + 2], 15, 718787259);
         b = 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 [a, b, c, d];
   }
   function binl2hex(binarray)
   {
      var hex_tab = "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;
   }
   function binl2b64(binarray)
   {
      var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
      var str = "";
      for (var i = 0; i < binarray.length * 32; i += 6)
      {
         str += tab.charAt(((binarray[i >> 5] << (i % 32)) & 0x3F) 
         | ((binarray[i >> 5 + 1] >> (32 - i % 32)) & 0x3F));
      }
      return str;
   }
   function str2binl(str)
   {
      var nblk = ((str.length + 8) >> 6) + 1;
      var blks = new Array(nblk * 16);
      for (var i = 0; i < nblk * 16; i++)
      {
         blks[i] = 0;
      }
      for (var i = 0; i < str.length; i++)
      {
         blks[i >> 2] |= (str.charCodeAt(i) & 0xFF) << ((i % 4) * 8);
      }
      blks[i >> 2] |= 0x80 << ((i % 4) * 8);
      blks[nblk * 16 - 2] = str.length * 8;
      return blks;
   }
   function strw2binl(str)
   {
      var nblk = ((str.length + 4) >> 5) + 1;
      var blks = new Array(nblk * 16);
      for (var i = 0; i < nblk * 16; i++)
      {
         blks[i] = 0;
      }
      for (var i = 0; i < str.length; i++)
      {
         blks[i >> 1] |= str.charCodeAt(i) << ((i % 2) * 16);
      }
      blks[i >> 1] |= 0x80 << ((i % 2) * 16);
      blks[nblk * 16 - 2] = str.length * 16;
      return blks;
   }
   function hexMD5(str){ return binl2hex(coreMD5(str2binl(str)))};
   function hexMD5w(str){  return binl2hex(coreMD5(strw2binl(str)))};
   function b64MD5(str){ return binl2b64(coreMD5(str2binl(str)))};
   function b64MD5w(str){ return binl2b64(coreMD5(strw2binl(str)))};
   function calcMD5(str){ return binl2hex(coreMD5(str2binl(str)))};
   return calcMD5(this);
};
//   -------------
//   usage:
//   
//   myString = 'alex';
//   crypted = myString.md5();
//   --------------