// Random number generator - requires a PRNG backend, e.g. prng4.js // Copyright (c) 2005 Tom Wu // All Rights Reserved. // See "LICENSE" for details. // Incapsulated by Francesco Sullo (www.sullof.com), december 2006 // For best results, put code like // // in your main HTML document. if (typeof JSBN != 'undefined') { JSBN.RNG = { rng_state: null, rng_pool: [], rng_pptr: 0, // Mix in a 32-bit integer into the pool rng_seed_int: function (x) { var RNG = JSBN.RNG; RNG.rng_pool[RNG.rng_pptr++] ^= x & 255; RNG.rng_pool[RNG.rng_pptr++] ^= (x >> 8) & 255; RNG.rng_pool[RNG.rng_pptr++] ^= (x >> 16) & 255; RNG.rng_pool[RNG.rng_pptr++] ^= (x >> 24) & 255; if(RNG.rng_pptr >= JSBN.PRNG4.rng_psize) RNG.rng_pptr -= JSBN.PRNG4.rng_psize; } , // Mix in the current time (w/milliseconds) into the pool rng_seed_time: function () { JSBN.RNG.rng_seed_int(new Date().getTime()); } , // Initialize the pool with junk if needed. pool_init: function () { var t, RNG = JSBN.RNG; if(navigator.appName == "Netscape" && navigator.appVersion < "5" && window.crypto) { // Extract entropy (256 bits) from NS4 RNG if available var z = window.crypto.random(32); for(t = 0; t < z.length; ++t) RNG.rng_pool[RNG.rng_pptr++] = z.charCodeAt(t) & 255; } while(RNG.rng_pptr < JSBN.PRNG4.rng_psize) { // extract some randomness from Math.random() t = Math.floor(65536 * Math.random()); RNG.rng_pool[RNG.rng_pptr++] = t >>> 8; RNG.rng_pool[RNG.rng_pptr++] = t & 255; } RNG.rng_pptr = 0; RNG.rng_seed_time(); //RNG.rng_seed_int(window.screenX); //RNG.rng_seed_int(window.screenY); } , rng_get_byte: function () { var RNG = JSBN.RNG; if(RNG.rng_state == null) { RNG.rng_seed_time(); RNG.rng_state = JSBN.PRNG4.prng_newstate(); RNG.rng_state.init(RNG.rng_pool); for(RNG.rng_pptr = 0; RNG.rng_pptr < RNG.rng_pool.length; ++RNG.rng_pptr) RNG.rng_pool[RNG.rng_pptr] = 0; RNG.rng_pptr = 0; //RNG.rng_pool = null; } // TODO: allow reseeding after first request return RNG.rng_state.next(); } , SecureRandom: function () { this.nextBytes = function (ba) { var i; for(i = 0; i < ba.length; ++i) ba[i] = JSBN.RNG.rng_get_byte(); } } } }; JSBN.RNG.pool_init();