sop / x509

	 *

	 * @return string

	 */

	public function firstDNS() {

		$gn = $this->firstOf(GeneralName::TAG_DNS_NAME);

		if (!$gn instanceof DNSName) {

			throw new \RuntimeException(

				DNSName::class . " expected, got " . get_class($gn));

		}

		return $gn->name();

	}

	/**

	 * Get value of the first 'directoryName' type.

	 *

	 * @return Name

	 */

	public function firstDN() {

		$gn = $this->firstOf(GeneralName::TAG_DIRECTORY_NAME);

		if (!$gn instanceof DirectoryName) {

			throw new \RuntimeException(

				DirectoryName::class . " expected, got " . get_class($gn));

		}

		return $gn->dn();

	}

	/**

	 * Get value of the first 'uniformResourceIdentifier' type.

	 *

	 * @return string

	 */

	public function firstURI() {

		$gn = $this->firstOf(GeneralName::TAG_URI);

		if (!$gn instanceof UniformResourceIdentifier) {

			throw new \RuntimeException(

				UniformResourceIdentifier::class . " expected, got " .

					 get_class($gn));

		}

		return $gn->uri();

	}

	/**

	 * Generate ASN.1 structure.