Jose\Behaviour\EncrypterTrait::getContentEncryptionAlgorithm PHP Метод

    private function getContentEncryptionAlgorithm(Object\JWEInterface $jwe)
    {
        $algorithm = null;
        foreach ($jwe->getRecipients() as $recipient) {
            $complete_headers = array_merge($jwe->getSharedProtectedHeaders(), $jwe->getSharedHeaders(), $recipient->getHeaders());
            Assertion::keyExists($complete_headers, 'enc', 'Parameter "enc" is missing.');
            if (null === $algorithm) {
                $algorithm = $complete_headers['enc'];
            } else {
                Assertion::eq($algorithm, $complete_headers['enc'], 'Foreign content encryption algorithms are not allowed.');
            }
        }
        $content_encryption_algorithm = $this->getJWAManager()->getAlgorithm($algorithm);
        Assertion::isInstanceOf($content_encryption_algorithm, Algorithm\ContentEncryptionAlgorithmInterface::class, sprintf('The content encryption algorithm "%s" is not supported or not a content encryption algorithm instance.', $algorithm));
        return $content_encryption_algorithm;
    }