js-encrypt/bin/lib/jsbn/rng.js

A Javascript library to perform OpenSSL RSA Encryption, Decryption, and Key Generation.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.SecureRandom = undefined;

var _prng = require("./prng4");

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

// Random number generator - requires a PRNG backend, e.g. prng4.js
var rng_state;
var rng_pool;
var rng_pptr;
var window;

// Initialize the pool with junk if needed.
if (rng_pool == null) {
  rng_pool = new Array();
  rng_pptr = 0;
  var t;
  if (window && window.crypto && window.crypto.getRandomValues) {
    // Extract entropy (2048 bits) from RNG if available
    var z = new Uint32Array(256);
    window.crypto.getRandomValues(z);
    for (t = 0; t < z.length; ++t) {
      rng_pool[rng_pptr++] = z[t] & 255;
    }
  }

  // Use mouse events for entropy, if we do not have enough entropy by the time
  // we need it, entropy will be generated by Math.random.
  var onMouseMoveListener = function onMouseMoveListener(ev) {
    this.count = this.count || 0;
    if (this.count >= 256 || rng_pptr >= _prng.rng_psize) {
      if (window.removeEventListener) window.removeEventListener("mousemove", onMouseMoveListener, false);else if (window.detachEvent) window.detachEvent("onmousemove", onMouseMoveListener);
      return;
    }
    try {
      var mouseCoordinates = ev.x + ev.y;
      rng_pool[rng_pptr++] = mouseCoordinates & 255;
      this.count += 1;
    } catch (e) {
      // Sometimes Firefox will deny permission to access event properties for some reason. Ignore.
    }
  };
  if (window && window.addEventListener) window.addEventListener("mousemove", onMouseMoveListener, false);else if (window && window.attachEvent) window.attachEvent("onmousemove", onMouseMoveListener);
}

function rng_get_byte() {
  if (rng_state == null) {
    rng_state = (0, _prng.prng_newstate)();
    // At this point, we may not have collected enough entropy.  If not, fall back to Math.random
    while (rng_pptr < _prng.rng_psize) {
      var random = Math.floor(65536 * Math.random());
      rng_pool[rng_pptr++] = random & 255;
    }
    rng_state.init(rng_pool);
    for (rng_pptr = 0; rng_pptr < rng_pool.length; ++rng_pptr) {
      rng_pool[rng_pptr] = 0;
    }rng_pptr = 0;
  }
  // 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();
  }
}

var SecureRandom = exports.SecureRandom = function SecureRandom() {
  _classCallCheck(this, SecureRandom);
};

SecureRandom.prototype.nextBytes = rng_get_bytes;