function Core_MD5 (x,
  len)
{
  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));
}

function MD5_CMN (q, a, b, x, s, t)
{
  return (Safe_Add (BitRol (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));
}

function CoreHMacMD5 (key,
  data)
{
  var bkey = Str2Binl (key);
  if (bkey.length > 16)
  {
    bkey = Core_MD5 (bkey, key.length * 8);
  }

  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 * 8);
  return (Core_MD5 (opad.concat(hash), 512 + 128));
}

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 BitRol (num,
  cnt)
{
  return ((num << cnt) | (num >>> (32 - cnt)));
}

function Str2Binl (str)
{
  var bin = Array ();
  var mask = 255;
  for (var i = 0; i < str.length * 8; i += 8)
  {
    bin[i>>5] |= (str.charCodeAt(i / 8) & mask) << (i%32);
  }
  return (bin);
}

function HexHMacMD5 (key,
  data)
{
  
  var hmac = CoreHMacMD5 (key, data);
  var hex_tab = "0123456789ABCDEF";
  var str = "";
  
  for (var i = 0; i < hmac.length * 4; i++)
  {
    str += hex_tab.charAt((hmac[i>>2] >> ((i%4)*8+4)) & 0xF) +
           hex_tab.charAt((hmac[i>>2] >> ((i%4)*8  )) & 0xF);
  }

  return (str);
}