public function getAudiences()
    {
        $audiences = array();

        $entries = $this->_queryAssertion('/saml:Conditions/saml:AudienceRestriction/saml:Audience');
        foreach ($entries as $entry) {
            $value = trim($entry->textContent);
            if (!empty($value)) {
                $audiences[] = $value;
            }
        }

        return array_unique($audiences);
    }