Reputation:

How Do I Generate Random Identicons?

I am looking for the most basic way to generate random identicons with no regards to information such as a user email or IP address etc.

Upvotes: 1

Answers (3)

Acorn

Reputation: 50557

I wrote this the other day: http://jsfiddle.net/pHv6W/

It will generate a random hexadecimal hash and display an identicon and a monsterID from gravatar.com

// Load the MD5 script
MD5 = makeMD5();

seed = randomString();

image = document.getElementById('image');
image2 = document.getElementById('image2');
hash = MD5.hex(seed);
image.src = 'http://www.gravatar.com/avatar/' + hash + '?d=identicon&s=150';
image2.src = 'http://www.gravatar.com/avatar/' + hash + '?d=monsterid&s=150';

function randomString(length) {
  var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz'.split('');

  if (!length) {
    length = Math.floor(Math.random() * chars.length);
  }

  var str = '';
  for (var i = 0; i < length; i++) {
    str += chars[Math.floor(Math.random() * chars.length)];
  }
  return str;
}

/*
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
 * Digest Algorithm, as defined in RFC 1321.
 * Version 2.1 Copyright (C) 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.
 */

function makeMD5() {
  /*
   * Calculate the MD5 of an array of little-endian words, and a bit length
   */
  function core_md5(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 = md5_ff(a, b, c, d, x[i + 0], 7, -680876936);
      d = md5_ff(d, a, b, c, x[i + 1], 12, -389564586);
      c = md5_ff(c, d, a, b, x[i + 2], 17, 606105819);
      b = md5_ff(b, c, d, a, x[i + 3], 22, -1044525330);
      a = md5_ff(a, b, c, d, x[i + 4], 7, -176418897);
      d = md5_ff(d, a, b, c, x[i + 5], 12, 1200080426);
      c = md5_ff(c, d, a, b, x[i + 6], 17, -1473231341);
      b = md5_ff(b, c, d, a, x[i + 7], 22, -45705983);
      a = md5_ff(a, b, c, d, x[i + 8], 7, 1770035416);
      d = md5_ff(d, a, b, c, x[i + 9], 12, -1958414417);
      c = md5_ff(c, d, a, b, x[i + 10], 17, -42063);
      b = md5_ff(b, c, d, a, x[i + 11], 22, -1990404162);
      a = md5_ff(a, b, c, d, x[i + 12], 7, 1804603682);
      d = md5_ff(d, a, b, c, x[i + 13], 12, -40341101);
      c = md5_ff(c, d, a, b, x[i + 14], 17, -1502002290);
      b = md5_ff(b, c, d, a, x[i + 15], 22, 1236535329);

      a = md5_gg(a, b, c, d, x[i + 1], 5, -165796510);
      d = md5_gg(d, a, b, c, x[i + 6], 9, -1069501632);
      c = md5_gg(c, d, a, b, x[i + 11], 14, 643717713);
      b = md5_gg(b, c, d, a, x[i + 0], 20, -373897302);
      a = md5_gg(a, b, c, d, x[i + 5], 5, -701558691);
      d = md5_gg(d, a, b, c, x[i + 10], 9, 38016083);
      c = md5_gg(c, d, a, b, x[i + 15], 14, -660478335);
      b = md5_gg(b, c, d, a, x[i + 4], 20, -405537848);
      a = md5_gg(a, b, c, d, x[i + 9], 5, 568446438);
      d = md5_gg(d, a, b, c, x[i + 14], 9, -1019803690);
      c = md5_gg(c, d, a, b, x[i + 3], 14, -187363961);
      b = md5_gg(b, c, d, a, x[i + 8], 20, 1163531501);
      a = md5_gg(a, b, c, d, x[i + 13], 5, -1444681467);
      d = md5_gg(d, a, b, c, x[i + 2], 9, -51403784);
      c = md5_gg(c, d, a, b, x[i + 7], 14, 1735328473);
      b = md5_gg(b, c, d, a, x[i + 12], 20, -1926607734);

      a = md5_hh(a, b, c, d, x[i + 5], 4, -378558);
      d = md5_hh(d, a, b, c, x[i + 8], 11, -2022574463);
      c = md5_hh(c, d, a, b, x[i + 11], 16, 1839030562);
      b = md5_hh(b, c, d, a, x[i + 14], 23, -35309556);
      a = md5_hh(a, b, c, d, x[i + 1], 4, -1530992060);
      d = md5_hh(d, a, b, c, x[i + 4], 11, 1272893353);
      c = md5_hh(c, d, a, b, x[i + 7], 16, -155497632);
      b = md5_hh(b, c, d, a, x[i + 10], 23, -1094730640);
      a = md5_hh(a, b, c, d, x[i + 13], 4, 681279174);
      d = md5_hh(d, a, b, c, x[i + 0], 11, -358537222);
      c = md5_hh(c, d, a, b, x[i + 3], 16, -722521979);
      b = md5_hh(b, c, d, a, x[i + 6], 23, 76029189);
      a = md5_hh(a, b, c, d, x[i + 9], 4, -640364487);
      d = md5_hh(d, a, b, c, x[i + 12], 11, -421815835);
      c = md5_hh(c, d, a, b, x[i + 15], 16, 530742520);
      b = md5_hh(b, c, d, a, x[i + 2], 23, -995338651);

      a = md5_ii(a, b, c, d, x[i + 0], 6, -198630844);
      d = md5_ii(d, a, b, c, x[i + 7], 10, 1126891415);
      c = md5_ii(c, d, a, b, x[i + 14], 15, -1416354905);
      b = md5_ii(b, c, d, a, x[i + 5], 21, -57434055);
      a = md5_ii(a, b, c, d, x[i + 12], 6, 1700485571);
      d = md5_ii(d, a, b, c, x[i + 3], 10, -1894986606);
      c = md5_ii(c, d, a, b, x[i + 10], 15, -1051523);
      b = md5_ii(b, c, d, a, x[i + 1], 21, -2054922799);
      a = md5_ii(a, b, c, d, x[i + 8], 6, 1873313359);
      d = md5_ii(d, a, b, c, x[i + 15], 10, -30611744);
      c = md5_ii(c, d, a, b, x[i + 6], 15, -1560198380);
      b = md5_ii(b, c, d, a, x[i + 13], 21, 1309151649);
      a = md5_ii(a, b, c, d, x[i + 4], 6, -145523070);
      d = md5_ii(d, a, b, c, x[i + 11], 10, -1120210379);
      c = md5_ii(c, d, a, b, x[i + 2], 15, 718787259);
      b = md5_ii(b, c, d, a, x[i + 9], 21, -343485551);

      a = safe_add(a, olda);
      b = safe_add(b, oldb);
      c = safe_add(c, oldc);
      d = safe_add(d, oldd);
    }
    return [a, b, c, d];
  }

  /*
   * These functions implement the four basic operations the algorithm uses.
   */
  function md5_cmn(q, a, b, x, s, t) {
    return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
  }

  function md5_ff(a, b, c, d, x, s, t) {
    return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);
  }

  function md5_gg(a, b, c, d, x, s, t) {
    return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);
  }

  function md5_hh(a, b, c, d, x, s, t) {
    return md5_cmn(b ^ c ^ d, a, b, x, s, t);
  }

  function md5_ii(a, b, c, d, x, s, t) {
    return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);
  }

  /*
   * Calculate the HMAC-MD5, of a key and some data
   */
  function core_hmac_md5(key, data) {
    var bkey = str2binl(key);
    if (bkey.length > 16) bkey = core_md5(bkey, key.length * MD5.chrsz);

    var ipad = [],
      opad = [];
    for (var i = 0; i < 16; i++) {
      ipad[i] = bkey[i] ^ 0x36363636;
      opad[i] = bkey[i] ^ 0x5C5C5C5C;
    }

    var hash = core_md5(ipad.concat(str2binl(data)), 512 + data.length * MD5.chrsz);
    return core_md5(opad.concat(hash), 512 + 128);
  }

  /*
   * 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 bit_rol(num, cnt) {
    return (num << cnt) | (num >>> (32 - cnt));
  }

  /*
   * Convert a string to an array of little-endian words
   * If chrsz is ASCII, characters >255 have their hi-byte silently ignored.
   */
  function str2binl(str) {
    var bin = [],
      chrsz = MD5.chrsz;
    var mask = (1 << chrsz) - 1;
    for (var i = 0; i < str.length * chrsz; i += chrsz)
      bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (i % 32);
    return bin;
  }

  /*
   * Convert an array of little-endian words to a string
   */
  function binl2str(bin) {
    var str = "",
      chrsz = MD5.chrsz;
    var mask = (1 << chrsz) - 1;
    for (var i = 0; i < bin.length * 32; i += chrsz)
      str += String.fromCharCode((bin[i >> 5] >>> (i % 32)) & mask);
    return str;
  }

  /*
   * Convert an array of little-endian words to a hex string.
   */
  function binl2hex(binarray) {
    var hex_tab = MD5.hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
    var str = "";
    for (var i = 0; i < binarray.length * 4; i++) {
      str += hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8 + 4)) & 0xF) +
        hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8)) & 0xF);
    }
    return str;
  }

  /*
   * Convert an array of little-endian words to a base-64 string
   */
  function binl2b64(binarray) {
    var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    var str = "";
    for (var i = 0; i < binarray.length * 4; i += 3) {
      var triplet = (((binarray[i >> 2] >> 8 * (i % 4)) & 0xFF) << 16) |
        (((binarray[i + 1 >> 2] >> 8 * ((i + 1) % 4)) & 0xFF) << 8) |
        ((binarray[i + 2 >> 2] >> 8 * ((i + 2) % 4)) & 0xFF);
      for (var j = 0; j < 4; j++) {
        if (i * 8 + j * 6 > binarray.length * 32) str += MD5.b64pad;
        else str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3F);
      }
    }
    return str;
  }

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

    /*
     * These are the functions you'll usually want to call
     * They take string arguments and return either hex or base-64 encoded strings
     */
    hex: function(s) {
      return binl2hex(core_md5(str2binl(s), s.length * MD5.chrsz));
    },

    base64: function(s) {
      return binl2b64(core_md5(str2binl(s), s.length * MD5.chrsz));
    },

    string: function(s) {
      return binl2str(core_md5(str2binl(s), s.length * MD5.chrsz));
    },

    hmac: {
      hex: function(key, data) {
        return binl2hex(core_hmac_md5(key, data));
      },

      base64: function(key, data) {
        return binl2b64(core_hmac_md5(key, data));
      },

      string: function(key, data) {
        return binl2str(core_hmac_md5(key, data));
      }
    },

    test: function() { // Perform a simple self-test to see if the VM is working
      return this.hex("abc") == "900150983cd24fb0d6963f7d28e17f72";
    }
  };
}