function _getOpenID1SessionType($assoc_response)
    {
        // If it's an OpenID 1 message, allow session_type to default
        // to None (which signifies "no-encryption")
        $session_type = $assoc_response->getArg(Auth_OpenID_OPENID1_NS,
                                                'session_type');

        // Handle the differences between no-encryption association
        // respones in OpenID 1 and 2:

        // no-encryption is not really a valid session type for OpenID
        // 1, but we'll accept it anyway, while issuing a warning.
        if ($session_type == 'no-encryption') {
            // oidutil.log('WARNING: OpenID server sent "no-encryption"'
            //             'for OpenID 1.X')
        } else if (($session_type == '') || ($session_type === null)) {
            // Missing or empty session type is the way to flag a
            // 'no-encryption' response. Change the session type to
            // 'no-encryption' so that it can be handled in the same
            // way as OpenID 2 'no-encryption' respones.
            $session_type = 'no-encryption';
        }

        return $session_type;
    }