Encrypting Data in JavaScript Using the SHA-1 Algorithm

Password Chameleon, the offline generator for site-specific passwords, uses the SHA-1 algorithm implemented in JavaScript to generate the hash (or the unique password).


 /*
  * A JavaScript implementation of the Secure Hash Algorithm, SHA-1,
  * as defined in FIPS PUB 180-1
  * Version 2.1 Copyright Paul Johnston 2000 - 2002.
  * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
  * Distributed under the BSD License
  * See http://pajhome.org.uk/crypt/md5 for details.
  */

 var b64pad  = "";
 var chrsz   = 8;

 function generate(secretpassword, sitename) {
     var pwd = "";
            var error = "";
     if (sitename.length == 0)
         error = error + " sitename";
     if (secretpassword.length == 0)
         error = error + " secretpassword";
     
     if (error.length == 0) {
         var input = secretpassword + ':' + sitename.toLowerCase();
         pwd = binb2b64(core_sha1(str2binb(input), input.length * chrsz));
         pwd = pwd.substring(0, 10);
         pwd = ensurenumberandletter(pwd);
     }
     return { password: pwd, error: error };
 }

 function core_sha1(x, len)
 {
  x[len >> 5] |= 0x80 << (24 - len % 32);
  x[((len + 64 >> 9) << 4) + 15] = len;

  var w = Array(80);
  var a =  1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d =  271733878;
  var e = -1009589776;

  for(var i = 0; i < x.length; i += 16)
  {
  var olda = a;
  var oldb = b;
  var oldc = c;
  var oldd = d;
  var olde = e;

  for(var j = 0; j < 80; j++)
  {
   if(j < 16) w[j] = x[i + j];
   else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
   var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),
           safe_add(safe_add(e, w[j]), sha1_kt(j)));
   e = d;
   d = c;
   c = rol(b, 30);
   b = a;
   a = t;
  }

  a = safe_add(a, olda);
  b = safe_add(b, oldb);
  c = safe_add(c, oldc);
  d = safe_add(d, oldd);
  e = safe_add(e, olde);
  }
  return Array(a, b, c, d, e);

 }

 function sha1_ft(t, b, c, d)
 {
  if(t < 20) return (b & c) | ((~b) & d);
  if(t < 40) return b ^ c ^ d;
  if(t < 60) return (b & c) | (b & d) | (c & d);
  return b ^ c ^ d;
 }

 function sha1_kt(t)
 {
  return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
         (t < 60) ? -1894007588 : -899497514;
 }

 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 str2binb(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) << (24 - i%32);
  return bin;
 }

 function binb2b64(binarray)
 {
  var tab = "ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz123456789?!#@&$";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i += 3)
  {
  var triplet = (((binarray[i >> 2] >> 8 * (3 - i%4)) & 0xFF) << 16)
           | (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )
           |  ((binarray[i+2 >> 2] >> 8 * (3 - (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;
 }

 function ensurenumberandletter(s) {
     var numbers = "123456789";
     var letters = "ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
     var punct = "?!#@&$";
     var hasnumber = 0;
     var hasletter = 0;
     var haspunct = 0;

     for (var i = 0; i < s.length; i++) {
         if (numbers.indexOf(s[i]) > -1)
             hasnumber = 1;
         if (letters.indexOf(s[i]) > -1)
             hasletter = 1;
         if (punct.indexOf(s[i]) > -1)
             haspunct = 1;
     }
     if (hasnumber == 0)
         s = "1" + s.substring(1);
     if (hasletter == 0)
         s = s.substring(0, 1) + "a" + s.substring(2);
     if (haspunct == 0)
         s = s.substring(0, 2) + "@" + s.substring(3);

     return s;
 }