code: function spawnPrng() {
    var ctx = forge.prng.create(prng_aes);
  
    /**
     * Gets random bytes. If a native secure crypto API is unavailable, this
     * method tries to make the bytes more unpredictable by drawing from data that
     * can be collected from the user of the browser, eg: mouse movement.
     *
     * If a callback is given, this method will be called asynchronously.
     *
     * @param count the number of random bytes to get.
     * @param [callback(err, bytes)] called once the operation completes.
     *
     * @return the random bytes in a string.
     */
    ctx.getBytes = function(count, callback) {
      return ctx.generate(count, callback);
    };
  
    /**
     * Gets random bytes asynchronously. If a native secure crypto API is
     * unavailable, this method tries to make the bytes more unpredictable by
     * drawing from data that can be collected from the user of the browser,
     * eg: mouse movement.
     *
     * @param count the number of random bytes to get.
     *
     * @return the random bytes in a string.
     */
    ctx.getBytesSync = function(count) {
      return ctx.generate(count);
    };
  
    return ctx;
  }
docs: Creates a new PRNG.