code: public synchronized static Random getSecureRandom() {
      if (cachedSecureRandom != null)
        return cachedSecureRandom;
      try {
        return SecureRandom.getInstance("SHA1PRNG");
      } catch (NoSuchAlgorithmException e) {
        return R;
      }
    }
docs: get an instance of a SecureRandom for creating storageid