100 lines
2.6 KiB
JavaScript
100 lines
2.6 KiB
JavaScript
//>>built
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// AMD-ID "dojox/math/random/Secure"
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define("dojox/math/random/Secure", ["dojo"], function(dojo) {
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// Copyright (c) 2005 Tom Wu
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// All Rights Reserved.
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// See "LICENSE-BigInteger" for details.
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// Random number generator - requires a PRNG backend, e.g. prng4.js
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dojo.declare("dojox.math.random.Secure", null, {
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// summary:
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// Super simple implementation of a random number generator,
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// which relies on Math.random().
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constructor: function(prng, noEvents){
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// summary:
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// Intializes an instance of a secure random generator.
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// prng: Function:
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// function that returns an instance of PRNG (pseudorandom number generator)
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// with two methods: init(array) and next(). It should have a property "size"
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// to indicate the required pool size.
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// noEvents: Boolean?:
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// if false or absent, onclick and onkeypress event will be used to add
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// "randomness", otherwise events will not be used.
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this.prng = prng;
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// Initialize the pool with junk if needed.
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var p = this.pool = new Array(prng.size);
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this.pptr = 0;
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for(var i = 0, len = prng.size; i < len;) { // extract some randomness from Math.random()
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var t = Math.floor(65536 * Math.random());
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p[i++] = t >>> 8;
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p[i++] = t & 255;
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}
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this.seedTime();
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if(!noEvents){
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this.h = [
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dojo.connect(dojo.body(), "onclick", this, "seedTime"),
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dojo.connect(dojo.body(), "onkeypress", this, "seedTime")
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];
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}
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},
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destroy: function(){
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// summary:
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// Disconnects events, if any, preparing the object for GC.
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if(this.h){
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dojo.forEach(this.h, dojo.disconnect);
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}
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},
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nextBytes: function(/* Array */ byteArray){
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// summary:
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// Fills in an array of bytes with random numbers
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// byteArray: Array:
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// array to be filled in with random numbers, only existing
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// elements will be filled.
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var state = this.state;
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if(!state){
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this.seedTime();
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state = this.state = this.prng();
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state.init(this.pool);
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for(var p = this.pool, i = 0, len = p.length; i < len; p[i++] = 0);
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this.pptr = 0;
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//this.pool = null;
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}
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for(var i = 0, len = byteArray.length; i < len; ++i){
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byteArray[i] = state.next();
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}
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},
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seedTime: function() {
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// summary:
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// Mix in the current time (w/milliseconds) into the pool
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this._seed_int(new Date().getTime());
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},
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_seed_int: function(x) {
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// summary:
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// Mix in a 32-bit integer into the pool
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var p = this.pool, i = this.pptr;
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p[i++] ^= x & 255;
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p[i++] ^= (x >> 8) & 255;
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p[i++] ^= (x >> 16) & 255;
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p[i++] ^= (x >> 24) & 255;
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if(i >= this.prng.size){
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i -= this.prng.size;
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}
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this.pptr = i;
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}
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});
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return dojox.math.random.Secure;
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});
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