code: function getBytes(len) {
      if (!len) {
          return new Uint8Array(0);
      }
      algo.getBytes(Math.round(Math.random() * len) + 1);
      var result = algo.getBytes(len);
      var cryptoBytes = CryptoEngine.random(len);
      for (var i = cryptoBytes.length - 1; i >= 0; --i) {
          result[i] ^= cryptoBytes[i];
      }
      return result;
  }
docs: Gets random bytes
  @param {number} len - bytes count
  @return {Uint8Array} - random bytes