使用音频和图形指纹技术在浏览器中生成极其持久的Cookie。
原理：通过getClientRects和AudioContext进行浏览器指纹识别
附上核心代码：
(function() {
// helper functions for that ctx
function write(buffer, offs) {
for (var i = 2; i < arguments.length; i++) {
for (var j = 0; j < arguments[i].length; j++) {
buffer[offs++] = arguments[i].charAt(j);
}
}
}
function byte2(w) {
return String.fromCharCode((w >> 8) & 255, w & 255);
}
function byte4(w) {
return String.fromCharCode((w >> 24) & 255, (w >> 16) & 255, (w >> 8) & 255, w & 255);
}
function byte2lsb(w) {
return String.fromCharCode(w & 255, (w >> 8) & 255);
}
window.PNGlib = function(width, height, depth) {
this.width = width;
this.height = height;
this.depth = depth;
// pixel data and row filter identifier size
this.pix_size = height * (width + 1);
// deflate header, pix_size, block headers, adler32 checksum
this.data_size = 2 + this.pix_size + 5 * Math.floor((0xfffe + this.pix_size) / 0xffff) + 4;
// offsets and sizes of Png chunks
this.ihdr_offs = 0; // IHDR offset and size
this.ihdr_size = 4 + 4 + 13 + 4;
this.plte_offs = this.ihdr_offs + this.ihdr_size; // PLTE offset and size
this.plte_size = 4 + 4 + 3 * depth + 4;
this.trns_offs = this.plte_offs + this.plte_size; // tRNS offset and size
this.trns_size = 4 + 4 + depth + 4;
this.idat_offs = this.trns_offs + this.trns_size; // IDAT offset and size
this.idat_size = 4 + 4 + this.data_size + 4;
this.iend_offs = this.idat_offs + this.idat_size; // IEND offset and size
this.iend_size = 4 + 4 + 4;
this.buffer_size = this.iend_offs + this.iend_size; // total PNG size
this.buffer = new Array();
this.palette = new Object();
this.pindex = 0;
var _crc32 = new Array();
// initialize buffer with zero bytes
for (var i = 0; i < this.buffer_size; i++) {
this.buffer[i] = "x00";
}
// initialize non-zero elements
write(this.buffer, this.ihdr_offs, byte4(this.ihdr_size - 12), 'IHDR', byte4(width), byte4(height), "x08x03");
write(this.buffer, this.plte_offs, byte4(this.plte_size - 12), 'PLTE');
write(this.buffer, this.trns_offs, byte4(this.trns_size - 12), 'tRNS');
write(this.buffer, this.idat_offs, byte4(this.idat_size - 12), 'IDAT');
write(this.buffer, this.iend_offs, byte4(this.iend_size - 12), 'IEND');
// initialize deflate header
var header = ((8 + (7 << 4)) << 8) | (3 << 6);
header += 31 - (header % 31);
write(this.buffer, this.idat_offs + 8, byte2(header));
// initialize deflate block headers
for (var i = 0;
(i << 16) - 1 < this.pix_size; i++) {
var size, bits;
if (i + 0xffff < this.pix_size) {
size = 0xffff;
bits = "x00";
} else {
size = this.pix_size - (i << 16) - i;
bits = "x01";
}
write(this.buffer, this.idat_offs + 8 + 2 + (i << 16) + (i << 2), bits, byte2lsb(size), byte2lsb(~size));
}
/* Create crc32 lookup table */
for (var i = 0; i < 256; i++) {
var c = i;
for (var j = 0; j < 8; j++) {
if (c & 1) {
c = -306674912 ^ ((c >> 1) & 0x7fffffff);
} else {
c = (c >> 1) & 0x7fffffff;
}
}
_crc32[i] = c;
}
// compute the index into a png for a given pixel
this.index = function(x, y) {
var i = y * (this.width + 1) + x + 1;
var j = this.idat_offs + 8 + 2 + 5 * Math.floor((i / 0xffff) + 1) + i;
return j;
}
// convert a color and build up the palette
this.color = function(red, green, blue, alpha) {
alpha = alpha >= 0 ? alpha : 255;
var color = (((((alpha << 8) | red) << 8) | green) << 8) | blue;
if (typeof this.palette[color] == "undefined") {
if (this.pindex == this.depth) return "x00";
var ndx = this.plte_offs + 8 + 3 * this.pindex;
this.buffer[ndx + 0] = String.fromCharCode(red);
this.buffer[ndx + 1] = String.fromCharCode(green);
this.buffer[ndx + 2] = String.fromCharCode(blue);
this.buffer[this.trns_offs + 8 + this.pindex] = String.fromCharCode(alpha);
this.palette[color] = String.fromCharCode(this.pindex++);
}
return this.palette[color];
}
// output a PNG string, Base64 encoded
this.getBase64 = function() {
var s = this.getDump();
var ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var c1, c2, c3, e1, e2, e3, e4;
var l = s.length;
var i = 0;
var r = "";
do {
c1 = s.charCodeAt(i);
e1 = c1 >> 2;
c2 = s.charCodeAt(i + 1);
e2 = ((c1 & 3) << 4) | (c2 >> 4);
c3 = s.charCodeAt(i + 2);
if (l < i + 2) { e3 = 64; } else { e3 = ((c2 & 0xf) << 2) | (c3 >> 6); }
if (l < i + 3) { e4 = 64; } else { e4 = c3 & 0x3f; }
r += ch.charAt(e1) + ch.charAt(e2) + ch.charAt(e3) + ch.charAt(e4);
} while ((i += 3) < l);
return r;
}
// output a PNG string
this.getDump = function() {
// compute adler32 of output pixels + row filter bytes
var BASE = 65521; /* largest prime smaller than 65536 */
var NMAX = 5552; /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
var s1 = 1;
var s2 = 0;
var n = NMAX;
for (var y = 0; y < this.height; y++) {
for (var x = -1; x < this.width; x++) {
s1 += this.buffer[this.index(x, y)].charCodeAt(0);
s2 += s1;
if ((n -= 1) == 0) {
s1 %= BASE;
s2 %= BASE;
n = NMAX;
}
}
}
s1 %= BASE;
s2 %= BASE;
write(this.buffer, this.idat_offs + this.idat_size - 8, byte4((s2 << 16) | s1));
// compute crc32 of the PNG chunks
function crc32(png, offs, size) {
var crc = -1;
for (var i = 4; i < size - 4; i += 1) {
crc = _crc32[(crc ^ png[offs + i].charCodeAt(0)) & 0xff] ^ ((crc >> 8) & 0x00ffffff);
}
write(png, offs + size - 4, byte4(crc ^ -1));
}
crc32(this.buffer, this.ihdr_offs, this.ihdr_size);
crc32(this.buffer, this.plte_offs, this.plte_size);
crc32(this.buffer, this.trns_offs, this.trns_size);
crc32(this.buffer, this.idat_offs, this.idat_size);
crc32(this.buffer, this.iend_offs, this.iend_size);
// convert PNG to string
return "211PNG
32
" + this.buffer.join('');
}
}
})();
(function() {
var PNGlib;
if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
PNGlib = require('./pnglib');
} else {
PNGlib = window.PNGlib;
}
var Identicon = function(hash, options) {
this.defaults = {
background: [255, 255, 255, 255],
hash: this.createHashFromString((new Date()).toISOString()),
margin: 0.08,
size: 64
};
this.options = typeof(options) === 'object' ? options : this.defaults;
// backward compatibility with old constructor (hash, size, margin)
if (arguments[1] && typeof(arguments[1]) === 'number') { this.options.size = arguments[1]; }
if (arguments[2]) { this.options.margin = arguments[2]; }
this.hash = hash || this.defaults.hash;
this.background = this.options.background || this.defaults.background;
this.margin = this.options.margin || this.defaults.margin;
this.size = this.options.size || this.defaults.size;
};
Identicon.prototype = {
background: null,
hash: null,
margin: null,
size: null,
render: function() {
var hash = this.hash,
size = this.size,
baseMargin = Math.floor(size * this.margin),
cell = Math.floor((size - (baseMargin * 2)) / 5),
margin = Math.floor((size - cell * 5) / 2),
image = new PNGlib(size, size, 256);
// light-grey background
var bg = image.color(this.background[0], this.background[1], this.background[2], this.background[3]);
// foreground is last 7 chars as hue at 50% saturation, 70% brightness
var rgb = this.hsl2rgb(parseInt(hash.substr(-7), 16) / 0xefefef, 0.8, 0.6),
fg = image.color(rgb[0] * 255, rgb[1] * 255, rgb[2] * 255);
// the first 15 characters of the hash control the pixels (even/odd)
// they are drawn down the middle first, then mirrored outwards
var i, color;
for (i = 0; i < 15; i++) {
color = parseInt(hash.charAt(i), 16) % 2 ? bg : fg;
if (i < 5) {
this.rectangle(2 * cell + margin, i * cell + margin, cell, cell, color, image);
} else if (i < 10) {
this.rectangle(1 * cell + margin, (i - 5) * cell + margin, cell, cell, color, image);
this.rectangle(3 * cell + margin, (i - 5) * cell + margin, cell, cell, color, image);
} else if (i < 15) {
this.rectangle(0 * cell + margin, (i - 10) * cell + margin, cell, cell, color, image);
this.rectangle(4 * cell + margin, (i - 10) * cell + margin, cell, cell, color, image);
}
}
return image;
},
rectangle: function(x, y, w, h, color, image) {
var i, j;
for (i = x; i < x + w; i++) {
for (j = y; j < y + h; j++) {
image.buffer[image.index(i, j)] = color;
}
}
},
// adapted from: https://gist.github.com/aemkei/1325937
hsl2rgb: function(h, s, b) {
h *= 6;
s = [
b += s *= b < .5 ? b : 1 - b,
b - h % 1 * s * 2,
b -= s *= 2,
b,
b + h % 1 * s,
b + s
];
return [
s[~~h % 6], // red
s[(h | 16) % 6], // green
s[(h | 8) % 6] // blue
];
},
toString: function() {
return this.render().getBase64();
},
// Creates a consistent-length hash from a string
createHashFromString: function(str) {
var hash = '0',
salt = 'identicon',
i, chr, len;
if (!str) {
return hash;
}
str += salt + str; // Better randomization for short inputs.
for (i = 0, len = str.length; i < len; i++) {
chr = str.charCodeAt(i);
hash = ((hash << 5) - hash) + chr;
hash |= 0; // Convert to 32bit integer
}
return hash.toString();
}
};
if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
module.exports = Identicon;
} else {
window.Identicon = Identicon;
}
})();
function updateIdenticon(elem, hash, size, color) {
var options = {
background : color,
size : size ? size : 256
}
//hash = hash.hexEncode();
var data = new Identicon(hash, options).toString();
// write to a data URI
elem.src = 'data:image/png;base64,' + data;
}
/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
var CryptoJS=CryptoJS||function(e,m){var p={},j=p.lib={},l=function(){},f=j.Base={extend:function(a){l.prototype=this;var c=new l;a&&c.mixIn(a);c.hasOwnProperty("init")||(c.init=function(){c.$super.init.apply(this,arguments)});c.init.prototype=c;c.$super=this;return c},create:function(){var a=this.extend();a.init.apply(a,arguments);return a},init:function(){},mixIn:function(a){for(var c in a)a.hasOwnProperty(c)&&(this[c]=a[c]);a.hasOwnProperty("toString")&&(this.toString=a.toString)},clone:function(){return this.init.prototype.extend(this)}},
n=j.WordArray=f.extend({init:function(a,c){a=this.words=a||[];this.sigBytes=c!=m?c:4*a.length},toString:function(a){return(a||h).stringify(this)},concat:function(a){var c=this.words,q=a.words,d=this.sigBytes;a=a.sigBytes;this.clamp();if(d%4)for(var b=0;b<a;b++)c[d+b>>>2]|=(q[b>>>2]>>>24-8*(b%4)&255)<<24-8*((d+b)%4);else if(65535<q.length)for(b=0;b<a;b+=4)c[d+b>>>2]=q[b>>>2];else c.push.apply(c,q);this.sigBytes+=a;return this},clamp:function(){var a=this.words,c=this.sigBytes;a[c>>>2]&=4294967295<<
32-8*(c%4);a.length=e.ceil(c/4)},clone:function(){var a=f.clone.call(this);a.words=this.words.slice(0);return a},random:function(a){for(var c=[],b=0;b<a;b+=4)c.push(4294967296*e.random()|0);return new n.init(c,a)}}),b=p.enc={},h=b.Hex={stringify:function(a){var c=a.words;a=a.sigBytes;for(var b=[],d=0;d<a;d++){var f=c[d>>>2]>>>24-8*(d%4)&255;b.push((f>>>4).toString(16));b.push((f&15).toString(16))}return b.join("")},parse:function(a){for(var c=a.length,b=[],d=0;d<c;d+=2)b[d>>>3]|=parseInt(a.substr(d,
2),16)<<24-4*(d%8);return new n.init(b,c/2)}},g=b.Latin1={stringify:function(a){var c=a.words;a=a.sigBytes;for(var b=[],d=0;d<a;d++)b.push(String.fromCharCode(c[d>>>2]>>>24-8*(d%4)&255));return b.join("")},parse:function(a){for(var c=a.length,b=[],d=0;d<c;d++)b[d>>>2]|=(a.charCodeAt(d)&255)<<24-8*(d%4);return new n.init(b,c)}},r=b.Utf8={stringify:function(a){try{return decodeURIComponent(escape(g.stringify(a)))}catch(c){throw Error("Malformed UTF-8 data");}},parse:function(a){return g.parse(unescape(encodeURIComponent(a)))}},
k=j.BufferedBlockAlgorithm=f.extend({reset:function(){this._data=new n.init;this._nDataBytes=0},_append:function(a){"string"==typeof a&&(a=r.parse(a));this._data.concat(a);this._nDataBytes+=a.sigBytes},_process:function(a){var c=this._data,b=c.words,d=c.sigBytes,f=this.blockSize,h=d/(4*f),h=a?e.ceil(h):e.max((h|0)-this._minBufferSize,0);a=h*f;d=e.min(4*a,d);if(a){for(var g=0;g<a;g+=f)this._doProcessBlock(b,g);g=b.splice(0,a);c.sigBytes-=d}return new n.init(g,d)},clone:function(){var a=f.clone.call(this);
a._data=this._data.clone();return a},_minBufferSize:0});j.Hasher=k.extend({cfg:f.extend(),init:function(a){this.cfg=this.cfg.extend(a);this.reset()},reset:function(){k.reset.call(this);this._doReset()},update:function(a){this._append(a);this._process();return this},finalize:function(a){a&&this._append(a);return this._doFinalize()},blockSize:16,_createHelper:function(a){return function(c,b){return(new a.init(b)).finalize(c)}},_createHmacHelper:function(a){return function(b,f){return(new s.HMAC.init(a,
f)).finalize(b)}}});var s=p.algo={};return p}(Math);
(function(){var e=CryptoJS,m=e.lib,p=m.WordArray,j=m.Hasher,l=[],m=e.algo.SHA1=j.extend({_doReset:function(){this._hash=new p.init([1732584193,4023233417,2562383102,271733878,3285377520])},_doProcessBlock:function(f,n){for(var b=this._hash.words,h=b[0],g=b[1],e=b[2],k=b[3],j=b[4],a=0;80>a;a++){if(16>a)l[a]=f[n+a]|0;else{var c=l[a-3]^l[a-8]^l[a-14]^l[a-16];l[a]=c<<1|c>>>31}c=(h<<5|h>>>27)+j+l[a];c=20>a?c+((g&e|~g&k)+1518500249):40>a?c+((g^e^k)+1859775393):60>a?c+((g&e|g&k|e&k)-1894007588):c+((g^e^
k)-899497514);j=k;k=e;e=g<<30|g>>>2;g=h;h=c}b[0]=b[0]+h|0;b[1]=b[1]+g|0;b[2]=b[2]+e|0;b[3]=b[3]+k|0;b[4]=b[4]+j|0},_doFinalize:function(){var f=this._data,e=f.words,b=8*this._nDataBytes,h=8