viernes, 19 de octubre de 2012

Codificador MD5 con Javascript



Interesante: Vídeo Tutorial de Javascript, aprende a programar Javascript desde cero.

La siguiente utilidad se trata de un codificador MD5 programado con Javascript, el hash MD5 es utilizado comunmente para la encriptación de datos tales como passwords.

DEMOSTRACIÓN





 
El código Javascript del codificador MD5 es el siguiente ...


<!-- By http://jquery-manual.blogspot.com -->
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript">
/*
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
 * Digest Algorithm, as defined in RFC 1321.
 * Copyright (C) Paul Johnston 1999 - 2000.
 * Updated by Greg Holt 2000 - 2001.
 * See http://pajhome.org.uk/site/legal.html for details.
 */

/*
 * Convert a 32-bit number to a hex string with ls-byte first
 */
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 calcMD5(str)
{
  x = str2blks_MD5(str);
  a =  1732584193;
  b = -271733879;
  c = -1732584194;
  d =  271733878;

  for(i = 0; i < x.length; i += 16)
  {
    olda = a;
    oldb = b;
    oldc = c;
    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); 
}
</script>
</head>
<body>
<center>
<input type="text" id="md5"><input type="button" value="Codificar a MD5" onclick="document.getElementById('resultado').innerHTML = calcMD5(document.getElementById('md5').value);">
<div id="resultado"></div>
</center>
</body>
</html>


Keywords: codificador, codificación, MD5, hash, Javascript