/*

 * A JavaScript implementation of the RSA Data Security, Inc. MD4 Message

 * Digest Algorithm, as defined in RFC 1320.

 * Copyright (C) Jerrad Pierce 2000. Distributed under the LGPL.

 * Updated by Paul Johnston 2000 - 2002.

 */



/*

 * Convert a 32-bit number to a hex string with ls-byte first

 */

var hex_chr = "0123456789abcdef";

function rhex(num)

{

  var str = "";

  for(var 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.

 * MD5 here is not a typo - this function is borrowed from the MD5 code.

 */

function str2blks_MD5(str)

{

  var nblk = ((str.length + 8) >> 6) + 1;

  var blks = new Array(nblk * 16);

  for(var i = 0; i < nblk * 16; i++) blks[i] = 0;

  for(var 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 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 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 safe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);

}

function ffMD4(a, b, c, d, x, s)

{

  return cmn((b & c) | ((~b) & d), a, 0, x, s, 0);

}

function ggMD4(a, b, c, d, x, s)

{

  return cmn((b & c) | (b & d) | (c & d), a, 0, x, s, 1518500249);

}

function hhMD4(a, b, c, d, x, s)

{

  return cmn(b ^ c ^ d, a, 0, x, s, 1859775393);

}



/*

 * Take a string and return the hex representation of its MD4.

 */

function calcMD4(str)

{

  var x = str2blks_MD5(str);

  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 = ffMD4(a, b, c, d, x[i+ 0], 3 );

    d = ffMD4(d, a, b, c, x[i+ 1], 7 );

    c = ffMD4(c, d, a, b, x[i+ 2], 11);

    b = ffMD4(b, c, d, a, x[i+ 3], 19);

    a = ffMD4(a, b, c, d, x[i+ 4], 3 );

    d = ffMD4(d, a, b, c, x[i+ 5], 7 );

    c = ffMD4(c, d, a, b, x[i+ 6], 11);

    b = ffMD4(b, c, d, a, x[i+ 7], 19);

    a = ffMD4(a, b, c, d, x[i+ 8], 3 );

    d = ffMD4(d, a, b, c, x[i+ 9], 7 );

    c = ffMD4(c, d, a, b, x[i+10], 11);

    b = ffMD4(b, c, d, a, x[i+11], 19);

    a = ffMD4(a, b, c, d, x[i+12], 3 );

    d = ffMD4(d, a, b, c, x[i+13], 7 );

    c = ffMD4(c, d, a, b, x[i+14], 11);

    b = ffMD4(b, c, d, a, x[i+15], 19);



    a = ggMD4(a, b, c, d, x[i+ 0], 3 );

    d = ggMD4(d, a, b, c, x[i+ 4], 5 );

    c = ggMD4(c, d, a, b, x[i+ 8], 9 );

    b = ggMD4(b, c, d, a, x[i+12], 13);

    a = ggMD4(a, b, c, d, x[i+ 1], 3 );

    d = ggMD4(d, a, b, c, x[i+ 5], 5 );

    c = ggMD4(c, d, a, b, x[i+ 9], 9 );

    b = ggMD4(b, c, d, a, x[i+13], 13);

    a = ggMD4(a, b, c, d, x[i+ 2], 3 );

    d = ggMD4(d, a, b, c, x[i+ 6], 5 );

    c = ggMD4(c, d, a, b, x[i+10], 9 );

    b = ggMD4(b, c, d, a, x[i+14], 13);

    a = ggMD4(a, b, c, d, x[i+ 3], 3 );

    d = ggMD4(d, a, b, c, x[i+ 7], 5 );

    c = ggMD4(c, d, a, b, x[i+11], 9 );

    b = ggMD4(b, c, d, a, x[i+15], 13);



    a = hhMD4(a, b, c, d, x[i+ 0], 3 );

    d = hhMD4(d, a, b, c, x[i+ 8], 9 );

    c = hhMD4(c, d, a, b, x[i+ 4], 11);

    b = hhMD4(b, c, d, a, x[i+12], 15);

    a = hhMD4(a, b, c, d, x[i+ 2], 3 );

    d = hhMD4(d, a, b, c, x[i+10], 9 );

    c = hhMD4(c, d, a, b, x[i+ 6], 11);

    b = hhMD4(b, c, d, a, x[i+14], 15);

    a = hhMD4(a, b, c, d, x[i+ 1], 3 );

    d = hhMD4(d, a, b, c, x[i+ 9], 9 );

    c = hhMD4(c, d, a, b, x[i+ 5], 11);

    b = hhMD4(b, c, d, a, x[i+13], 15);

    a = hhMD4(a, b, c, d, x[i+ 3], 3 );

    d = hhMD4(d, a, b, c, x[i+11], 9 );

    c = hhMD4(c, d, a, b, x[i+ 7], 11);

    b = hhMD4(b, c, d, a, x[i+15], 15);



    a = safe_add(a, olda);

    b = safe_add(b, oldb);

    c = safe_add(c, oldc);

    d = safe_add(d, oldd);



  }

  return rhex(a) + rhex(b) + rhex(c) + rhex(d);

}