symfony共享主机CSPRNG错误

Question

我在共享主机上部署了我的symfony 3（和2.8）。但是在表单将呈现的任何页面中我都会收到此错误：

There is no suitable CSPRNG installed on your system

500 Internal Server Error - Exception

Stack Trace

in vendor/paragonie/random_compat/lib/random.php at line 185   -
         */
        function random_bytes($length)
        {
            throw new Exception(
                'There is no suitable CSPRNG installed on your system'
            );
        }
at random_bytes ('32')