四:MD4算法

/*
 * A JavaScript implementation of the RSA Data Security, Inc. MD4 Message
 * Digest Algorithm, as defined in RFC 1320.
 * Version 2.1 Copyright (C) Jerrad Pierce, Paul Johnston 1999 - 2002.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for more info.
 */

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */
var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad  = ""; /* base-64 pad character. "=" for strict RFC compliance   */
var chrsz   = 8;  /* bits per input character. 8 - ASCII; 16 - Unicode      */

/*
 * These are the functions you'll usually want to call
 */
function hex_md4(s){ return binl2hex(core_md4(str2binl(s), s.length * chrsz));}
function b64_md4(s){ return binl2b64(core_md4(str2binl(s), s.length * chrsz));}
function str_md4(s){ return binl2str(core_md4(str2binl(s), s.length * chrsz));}
function hex_hmac_md4(key, data) { return binl2hex(core_hmac_md4(key, data)); }
function b64_hmac_md4(key, data) { return binl2b64(core_hmac_md4(key, data)); }
function str_hmac_md4(key, data) { return binl2str(core_hmac_md4(key, data)); }

/* 
 * Perform a simple self-test to see if the VM is working 
 */
function md4_vm_test()
{
  return hex_md4("abc") == "a448017aaf21d8525fc10ae87aa6729d";
}

/*
 * Calculate the MD4 of an array of little-endian words, and a bit length
 */
function core_md4(x, len)
{
  /* append padding */
  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 = md4_ff(a, b, c, d, x[i+ 0], 3 );
    d = md4_ff(d, a, b, c, x[i+ 1], 7 );
    c = md4_ff(c, d, a, b, x[i+ 2], 11);
    b = md4_ff(b, c, d, a, x[i+ 3], 19);
    a = md4_ff(a, b, c, d, x[i+ 4], 3 );
    d = md4_ff(d, a, b, c, x[i+ 5], 7 );
    c = md4_ff(c, d, a, b, x[i+ 6], 11);
    b = md4_ff(b, c, d, a, x[i+ 7], 19);
    a = md4_ff(a, b, c, d, x[i+ 8], 3 );
    d = md4_ff(d, a, b, c, x[i+ 9], 7 );
    c = md4_ff(c, d, a, b, x[i+10], 11);
    b = md4_ff(b, c, d, a, x[i+11], 19);
    a = md4_ff(a, b, c, d, x[i+12], 3 );
    d = md4_ff(d, a, b, c, x[i+13], 7 );
    c = md4_ff(c, d, a, b, x[i+14], 11);
    b = md4_ff(b, c, d, a, x[i+15], 19);

    a = md4_gg(a, b, c, d, x[i+ 0], 3 );
    d = md4_gg(d, a, b, c, x[i+ 4], 5 );
    c = md4_gg(c, d, a, b, x[i+ 8], 9 );
    b = md4_gg(b, c, d, a, x[i+12], 13);
    a = md4_gg(a, b, c, d, x[i+ 1], 3 );
    d = md4_gg(d, a, b, c, x[i+ 5], 5 );
    c = md4_gg(c, d, a, b, x[i+ 9], 9 );
    b = md4_gg(b, c, d, a, x[i+13], 13);
    a = md4_gg(a, b, c, d, x[i+ 2], 3 );
    d = md4_gg(d, a, b, c, x[i+ 6], 5 );
    c = md4_gg(c, d, a, b, x[i+10], 9 );
    b = md4_gg(b, c, d, a, x[i+14], 13);
    a = md4_gg(a, b, c, d, x[i+ 3], 3 );
    d = md4_gg(d, a, b, c, x[i+ 7], 5 );
    c = md4_gg(c, d, a, b, x[i+11], 9 );
    b = md4_gg(b, c, d, a, x[i+15], 13);

    a = md4_hh(a, b, c, d, x[i+ 0], 3 );
    d = md4_hh(d, a, b, c, x[i+ 8], 9 );
    c = md4_hh(c, d, a, b, x[i+ 4], 11);
    b = md4_hh(b, c, d, a, x[i+12], 15);
    a = md4_hh(a, b, c, d, x[i+ 2], 3 );
    d = md4_hh(d, a, b, c, x[i+10], 9 );
    c = md4_hh(c, d, a, b, x[i+ 6], 11);
    b = md4_hh(b, c, d, a, x[i+14], 15);
    a = md4_hh(a, b, c, d, x[i+ 1], 3 );
    d = md4_hh(d, a, b, c, x[i+ 9], 9 );
    c = md4_hh(c, d, a, b, x[i+ 5], 11);
    b = md4_hh(b, c, d, a, x[i+13], 15);
    a = md4_hh(a, b, c, d, x[i+ 3], 3 );
    d = md4_hh(d, a, b, c, x[i+11], 9 );
    c = md4_hh(c, d, a, b, x[i+ 7], 11);
    b = md4_hh(b, c, d, a, x[i+15], 15);

    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(