diff options
| author | ausiv4 <ausiv4@eb105b4a-77de-11de-a249-6bf219df57d5> | 2009-07-24 13:57:46 +0000 |
|---|---|---|
| committer | ausiv4 <ausiv4@eb105b4a-77de-11de-a249-6bf219df57d5> | 2009-07-24 13:57:46 +0000 |
| commit | 40fd75696b548d18057a289e849be98dd2af12dd (patch) | |
| tree | 33ba504f1f4f84d9703f1229e26a085dc5a118a3 /proper-random/javascript/rng.js | |
| parent | 0cb5d281c18588c3b6567e8773ebad8acdb263a9 (diff) | |
Not what I meant to do...
Diffstat (limited to 'proper-random/javascript/rng.js')
| -rw-r--r-- | proper-random/javascript/rng.js | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/proper-random/javascript/rng.js b/proper-random/javascript/rng.js new file mode 100644 index 0000000..03afc3a --- /dev/null +++ b/proper-random/javascript/rng.js @@ -0,0 +1,68 @@ +// Random number generator - requires a PRNG backend, e.g. prng4.js + +// For best results, put code like +// <body onClick='rng_seed_time();' onKeyPress='rng_seed_time();'> +// 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; |