/* basic entropy accumulator */
var accum = (function() {
var pool, // randomness pool
time, // start timestamp
last; // last step timestamp
/* initialize with default pool */
function init() {
pool = [];
time = new Date().getTime();
last = time;
// use Math.random
pool.push((Math.random() * 0xffffffff)|0);
// use current time
pool.push(time|0);
}
/* perform one step */
function step() {
if (!to)
return;
if (pool.length >= 255) { // stop at 255 values (1 more is added on fetch)
stop();
return;
}
var now = new Date().getTime();
// use actual time difference
pool.push(now-last);
// always compute, occasionally use Math.random
var rnd = (Math.random() * 0xffffffff)|0;
if (now % 2)
pool[pool.length-1] += rnd;
last = now;
to = setTimeout(step, 100+Math.random()*512); // use hypothetical time difference
}
var to = null;
/* starts accumulating */
function start() {
if (to) return;
to = setTimeout(step, 100+Math.random()*512);
if (console.log)
console.log("bcrypt-isaac: collecting entropy...");
// install collectors
if (typeof window !== 'undefined' && window && window.addEventListener)
window.addEventListener("load", loadCollector, false),
window.addEventListener("mousemove", mouseCollector, false),
window.addEventListener("touchmove", touchCollector, false);
else if (typeof document !== 'undefined' && document && document.attachEvent)
document.attachEvent("onload", loadCollector),
document.attachEvent("onmousemove", mouseCollector);
}
/* stops accumulating */
function stop() {
if (!to) return;
clearTimeout(to); to = null;
// uninstall collectors
if (typeof window !== 'undefined' && window && window.removeEventListener)
window.removeEventListener("load", loadCollector, false),
window.removeEventListener("mousemove", mouseCollector, false),
window.removeEventListener("touchmove", touchCollector, false);
else if (typeof document !== 'undefined' && document && document.detachEvent)
document.detachEvent("onload", loadCollector),
document.detachEvent("onmousemove", mouseCollector);
}
/* fetches the randomness pool */
function fetch() {
// add overall time difference
pool.push((new Date().getTime()-time)|0);
var res = pool;
init();
if (console.log)
console.log("bcrypt-isaac: using "+res.length+"/256 samples of entropy");
// console.log(res);
return res;
}
/* adds the current time to the top of the pool */
function addTime() {
pool[pool.length-1] += new Date().getTime() - time;
}
/* page load collector */
function loadCollector() {
if (!to || pool.length >= 255)
return;
pool.push(0);
addTime();
}
/* mouse events collector */
function mouseCollector(ev) {
if (!to || pool.length >= 255)
return;
try {
var x = ev.x || ev.clientX || ev.offsetX || 0,
y = ev.y || ev.clientY || ev.offsetY || 0;
if (x != 0 || y != 0)
pool[pool.length-1] += ((x-mouseCollector.last[0]) ^ (y-mouseCollector.last[1])),
addTime(),
mouseCollector.last = [x,y];
} catch (e) {}
}
mouseCollector.last = [0,0];
/* touch events collector */
function touchCollector(ev) {
if (!to || pool.length >= 255)
return;
try {
var touch = ev.touches[0] || ev.changedTouches[0];
var x = touch.pageX || touch.clientX || 0,
y = touch.pageY || touch.clientY || 0;
if (x != 0 || y != 0)
pool[pool.length-1] += (x-touchCollector.last[0]) ^ (y-touchCollector.last[1]),
addTime(),
touchCollector.last = [x,y];
} catch (e) {}
}
touchCollector.last = [0,0];
init();
return {
"start": start,
"stop": stop,
"fetch": fetch
}
})();
