Namshi\JOSE\Signer\OpenSSL\ECDSA::supportsKey PHP Метод

    protected function supportsKey($key)
    {
        if (false === parent::supportsKey($key)) {
            return false;
        }
        // openssl_sign with EC keys was introduced in this PHP release
        $minVersions = array('5.4' => '5.4.26', '5.5' => '5.5.10', '5.6' => '5.6.0');
        if (isset($minVersions[PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION]) && version_compare(PHP_VERSION, $minVersions[PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION], '<')) {
            return false;
        }
        $keyDetails = openssl_pkey_get_details($key);
        if (0 === preg_match('/-----BEGIN PUBLIC KEY-----([^-]+)-----END PUBLIC KEY-----/', $keyDetails['key'], $matches)) {
            return false;
        }
        $publicKey = trim($matches[1]);
        $asn1 = new ASN1();
        /*
         * http://tools.ietf.org/html/rfc3279#section-2.2.3
         * AlgorithmIdentifier ::= SEQUENCE {
         *     algorithm OBJECT IDENTIFIER,
         *     parameters ANY DEFINED BY algorithm OPTIONAL
         * }
         * For ECDSA Signature Algorithm:
         * algorithm: ansi-X9-62 => 1.2.840.10045.2.1
         * parameters: id-ecSigType => 1.2.840.10045.x.y.z
         *
         */
        $asnAlgorithmIdentifier = array('type' => ASN1::TYPE_SEQUENCE, 'children' => array('ansi-X9-62' => array('type' => ASN1::TYPE_OBJECT_IDENTIFIER), 'id-ecSigType' => array('type' => ASN1::TYPE_OBJECT_IDENTIFIER)));
        /*
         * http://tools.ietf.org/html/rfc5280#section-4.1
         * SubjectPublicKeyInfo ::= SEQUENCE {
         *     algorithm AlgorithmIdentifier,
         *     subjectPublicKey BIT STRING
         * }
         */
        $asnSubjectPublicKeyInfo = array('type' => ASN1::TYPE_SEQUENCE, 'children' => array('algorithm' => $asnAlgorithmIdentifier, 'subjectPublicKey' => array('type' => ASN1::TYPE_BIT_STRING)));
        $decoded = $asn1->decodeBER(base64_decode($publicKey));
        $mappedDetails = $asn1->asn1map($decoded[0], $asnSubjectPublicKeyInfo);
        return isset($mappedDetails['algorithm']['id-ecSigType']) ? $this->getSupportedECDSACurve() === $mappedDetails['algorithm']['id-ecSigType'] : false;
    }