final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final PrimaryCipher cipher = ComponentUtil.getPrimaryCipher();
        userCode = cipher.encrypt(userCode);
        if (fessConfig.isValidUserCode(userCode)) {
            return userCode;
        }
        return null;
    }

    public void deleteUserCodeFromCookie(final HttpServletRequest request) {