Javascript implementation of the Fortuna PRNG
npm install javascript-fortunaJavascript implementation of the Fortuna PRNG.
npm i javascript-fortuna
This is a quick out-of-the-box usage example. This is not how you'd use it in production if you want it to be secure, but it will give you a decent random number.
``javascript
const fortuna = require('javascript-fortuna');
fortuna.init();
const randomNumber = fortuna.random();
console.log(I picked ${randomNumber}!);`
Javascript Fortuna comes with a simple command-line app that will generate a single random number seeded by your local environment.
`shell`
$ js-fortuna
0.7947502068732222
To reduce predictability add entropy from dynamic sytem state inforation such as CPU usage, number of active processes, availalbe ram and disk io.
`javascript
const fortuna = require('javascript-fortuna');
const si = require('systeminformation');
const sha512 = require('js-sha512');
const jsspg = require('javascript-strong-password-generator');
function entropyAccumFunction() {
return new Promise(async (resolve) => {
const cpuSpeed = await si.cpu();
const processes = await si.processes();
const disksIO = await si.disksIO();
const memory = await si.mem();
jsspg.entropyVal = sha512(${JSON.stringify(cpuSpeed)}:${JSON.stringify(processes)}:${JSON.stringify(disksIO)}:${JSON.stringify(memory)});
console.log(ent: ${jsspg.entropyVal});
resolve();
});
}
function entropyFunction() {
return jsspg.entropyVal;
}
let entropyInterval = setInterval(async () => {
await entropyAccumFunction();
}, 250);
jsspg.initialized = true;
fortuna.init({ timeBasedEntropy: true, accumulateTimeout: 100, entropyFxn: entropyFunction });
const num1 = fortuna.random();
console.log(I picked ${num1}!);
setTimeout(() => {
const num1 = fortuna.random();
console.log(I picked ${num1}!);`
fortuna.stopTimer();
clearInterval(entropyInterval);
}, 5000);
This will generate a ./build/fortuna.min.js file for use in a web browser.
`shell`
$ npm run webpack
`javascript`
Fortuna is a method of generating random numbers using AES encryption and an environment-based seed. It is more secure than simply using Math.random().
#### Options [{ k: v }]
- entropyFxn [function fxn()]: Custom entropy function. Must return an Array or string of length fortuna.entropySz (128 by default)
- timeBasedEntropy [bool]: Detaches the reseeding of the algorithm from the call to random().
- accumulateTimeout [int]: The amount of time in milliseconds between each timeBasedEntropy call. Requires timeBasedEntropy to be true.
Generates a random floating point value (0,1).
If you need an integer between min and max you can simply
`javascript``
const min = 4;
const max = 10;
const randomInt = parseInt((fortuna.random() * (max - min)) + min);