// random number generator - requires a prng backend, e.g. prng4.js // for best results, put code like // // in your main html document. var rng_state; var rng_pool; var rng_pptr; // mix in a 32-bit integer into the pool function rng_seed_int(x) { rng_pool[rng_pptr++] ^= x & 255; rng_pool[rng_pptr++] ^= (x >> 8) & 255; rng_pool[rng_pptr++] ^= (x >> 16) & 255; rng_pool[rng_pptr++] ^= (x >> 24) & 255; if(rng_pptr >= rng_psize) rng_pptr -= rng_psize; } // mix in the current time (w/milliseconds) into the pool function rng_seed_time() { rng_seed_int(new date().gettime()); } // initialize the pool with junk if needed. if(rng_pool == null) { rng_pool = new array(); rng_pptr = 0; var t; 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_pool[rng_pptr++] = z.charcodeat(t) & 255; } while(rng_pptr < rng_psize) { // extract some randomness from math.random() t = math.floor(65536 * math.random()); rng_pool[rng_pptr++] = t >>> 8; rng_pool[rng_pptr++] = t & 255; } rng_pptr = 0; rng_seed_time(); //rng_seed_int(window.screenx); //rng_seed_int(window.screeny); } function rng_get_byte() { if(rng_state == null) { rng_seed_time(); rng_state = prng_newstate(); rng_state.init(rng_pool); for(rng_pptr = 0; rng_pptr < rng_pool.length; ++rng_pptr) rng_pool[rng_pptr] = 0; rng_pptr = 0; //rng_pool = null; } // todo: allow reseeding after first request return rng_state.next(); } function rng_get_bytes(ba) { var i; for(i = 0; i < ba.length; ++i) ba[i] = rng_get_byte(); } function securerandom() {} securerandom.prototype.nextbytes = rng_get_bytes;