
var hex_chr = "0123456789abcdef";
function rhex(num)
{
  str = "";
  for(j = 0; j <= 3; j++)
    str += hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) +
           hex_chr.charAt((num >> (j * 8)) & 0x0F);
  return str;
}

/*
 * Convert a string to a sequence of 16-word blocks, stored as an array.
 * Append padding bits and the length, as described in the MD5 standard.
 */
function str2blks_MD5(str)
{
  nblk = ((str.length + 8) >> 6) + 1;
  blks = new Array(nblk * 16);
  for(i = 0; i < nblk * 16; i++) blks[i] = 0;
  for(i = 0; i < str.length; i++)
    blks[i >> 2] |= str.charCodeAt(i) << ((i % 4) * 8);
  blks[i >> 2] |= 0x80 << ((i % 4) * 8);
  blks[nblk * 16 - 2] = str.length * 8;
  return blks;
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally 
 * to work around bugs in some JS interpreters.
 */
function 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 rol(num, cnt)
{
  return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * These functions implement the basic operation for each round of the
 * algorithm.
 */
function cmn(q, a, b, x, s, t)
{
  return add(rol(add(add(a, q), 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);
}

/*
 * Take a string and return the hex representation of its MD5.
 */
function MD5(str)
{
  x = str2blks_MD5(str);
  var a =  1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d =  271733878;
 
  for(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 = add(a, olda);
    b = add(b, oldb);
    c = add(c, oldc);
    d = add(d, oldd);
  }
  return rhex(a) + rhex(b) + rhex(c) + rhex(d);
}

function valid_js() {
   // anything that claims NS 4 or higher functionality better work 
   if (navigator.userAgent.indexOf("Mozilla/") == 0) {
      return (parseInt(navigator.appVersion) >= 4);
   }
   return false;
}
 
function hash(form,login_url) {
    // this is Javascript enabled browser
    //document.login_form[".js"].value=1;
    // rudimentary check for a 4.x brower. should catch IE4+ and NS4.*
    var url;

    if (arguments.length > 1 && login_url != "") { // in case login_url is not passed in
      url = login_url;
    } else {
      url = "http://login.fkoo.com/config/login";
    }
    url += "?";
      
    if (valid_js()) {
      var passwd = form.passwd.value;
      var challenge = form[".challenge"].value;
      var hash2 = MD5(form.passwd.value) + challenge;
      var hash;
      if(form.passwd.value){
        hash=MD5(hash2);
      } else {
        hash="";
      }
      var js = 0;

      for(i=0; i<form.elements.length; i++){
        if(form.elements[i].name.length <=0) {
          continue;
        }
        if(i > 0){
          url += "&";
        }
        url += form.elements[i].name;
        url += "=";
        if(form.elements[i].name == "passwd"){
          url += hash;
        } else if (form.elements[i].type == "checkbox" && !form.elements[i].checked) {
          url += "";
        } else if (form.elements[i].type == "radio" && !form.elements[i].checked) {
          url += "";
        } else if (form.elements[i].name == ".save"){
          url += "1"; // "Sign in" causes problem with the space
        } else if (form.elements[i].name == ".js"){
          js = 1;
          url += "1"; 
        } else {
          url += escape(form.elements[i].value);
        }
      }
      // indicate the password is hashed.
      url += "&.hash=1";
      if(js == 0){
        url += "&.js=1";
      }
      url += "&.md5=1";
      //alert("url=" + url);
      location.href=url;
      // prevent from running this again. Allow the server response to submit the form directly
      form.onsubmit=null;

      // abort normal form submission
      return false;
    }
    // allow normal form submission
    return true;
}
