function mailcloak_md5() {

  // create a container to prevent variable name conflicts
  var md5obj = new Object();


  /* ---------------------------------------------------------
     From: http://pajhome.org.uk/crypt/md5

     Note: These are only the functions used by Mailcloak.
     This is the original code.
     --------------------------------------------------------- */

  /*
   * 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      */


  function hex_md5(s){ return binl2hex(core_md5(str2binl(s), s.length * chrsz));}


  /*
   * 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);
  }

  /*
   * 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 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;
  }


  // define functions as methods of object

  md5obj.hex_md5 = hex_md5;
  md5obj.core_md5 = core_md5;
  md5obj.md5_cmn = md5_cmn;
  md5obj.md5_ff = md5_ff;
  md5obj.md5_gg = md5_gg;
  md5obj.md5_hh = md5_hh;
  md5obj.md5_ii = md5_ii;
  md5obj.safe_add = safe_add;
  md5obj.bit_rol = bit_rol;
  md5obj.str2binl = str2binl;
  md5obj.binl2hex = binl2hex;

  return md5obj;

  // end of outer function

}