/* * @(#)X509Extension.java 1.22 03/12/19 * * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package java.security.cert; import java.util.Set; /** * Interface for an X.509 extension. * *

The extensions defined for X.509 v3 * {@link X509Certificate Certificates} and v2 * {@link X509CRL CRLs} (Certificate Revocation * Lists) provide methods * for associating additional attributes with users or public keys, * for managing the certification hierarchy, and for managing CRL * distribution. The X.509 extensions format also allows communities * to define private extensions to carry information unique to those * communities. * *

Each extension in a certificate/CRL may be designated as * critical or non-critical. A certificate/CRL-using system (an application * validating a certificate/CRL) must reject the certificate/CRL if it * encounters a critical extension it does not recognize. A non-critical * extension may be ignored if it is not recognized. *

* The ASN.1 definition for this is: * 

 * Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
 *
 * Extension  ::=  SEQUENCE  {
 *     extnId        OBJECT IDENTIFIER,
 *     critical      BOOLEAN DEFAULT FALSE,
 *     extnValue     OCTET STRING
 *                   -- contains a DER encoding of a value
 *                   -- of the type registered for use with
 *                   -- the extnId object identifier value
 * }
 *
* Since not all extensions are known, the getExtensionValue * method returns the DER-encoded OCTET STRING of the * extension value (i.e., the extnValue). This can then * be handled by a Class that understands the extension. * * @author Hemma Prafullchandra * @version 1.22 03/12/19 */ public interface X509Extension { /** * Check if there is a critical extension that is not supported. * * @return true if a critical extension is found that is * not supported, otherwise false. */ public boolean hasUnsupportedCriticalExtension(); /** * Gets a Set of the OID strings for the extension(s) marked * CRITICAL in the certificate/CRL managed by the object * implementing this interface. * * Here is sample code to get a Set of critical extensions from an * X509Certificate and print the OIDs: * 

     * InputStream inStrm = new FileInputStream("DER-encoded-Cert");
     * CertificateFactory cf = CertificateFactory.getInstance("X.509");
     * X509Certificate cert = (X509Certificate)cf.generateCertificate(inStrm);
     * inStrm.close();

     *
     * Set critSet = cert.getCriticalExtensionOIDs();
     * if (critSet != null && !critSet.isEmpty()) {
     *     System.out.println("Set of critical extensions:");
     *     for (Iterator i = critSet.iterator(); i.hasNext();) {
     *         String oid = (String)i.next();
     *         System.out.println(oid);
     *     }
     * }
     *
* @return a Set (or an empty Set if none are marked critical) of * the extension OID strings for extensions that are marked critical. * If there are no extensions present at all, then this method returns * null. */ public Set getCriticalExtensionOIDs(); /** * Gets a Set of the OID strings for the extension(s) marked * NON-CRITICAL in the certificate/CRL managed by the object * implementing this interface. * * Here is sample code to get a Set of non-critical extensions from an * X509CRL revoked certificate entry and print the OIDs: * 

     * InputStream inStrm = new FileInputStream("DER-encoded-CRL");
     * CertificateFactory cf = CertificateFactory.getInstance("X.509");
     * X509CRL crl = (X509CRL)cf.generateCRL(inStrm);
     * inStrm.close();

     *
     * byte[] certData = <DER-encoded certificate data>
     * ByteArrayInputStream bais = new ByteArrayInputStream(certData);
     * X509Certificate cert = (X509Certificate)cf.generateCertificate(bais);
     * bais.close();
     * X509CRLEntry badCert =
     *              crl.getRevokedCertificate(cert.getSerialNumber());

     *
     * if (badCert != null) {
     *     Set nonCritSet = badCert.getNonCriticalExtensionOIDs();

     *     if (nonCritSet != null)
     *         for (Iterator i = nonCritSet.iterator(); i.hasNext();) {
     *             String oid = (String)i.next();
     *             System.out.println(oid);
     *         }
     * }
     *
* * @return a Set (or an empty Set if none are marked non-critical) of * the extension OID strings for extensions that are marked non-critical. * If there are no extensions present at all, then this method returns * null. */ public Set getNonCriticalExtensionOIDs(); /** * Gets the DER-encoded OCTET string for the extension value * (extnValue) identified by the passed-in oid * String. * The oid string is * represented by a set of nonnegative whole numbers separated * by periods. * *

For example:
* * * * * * * * * * * * * * * * * * * * * * * * *
OID (Object Identifier)Extension Name
2.5.29.14SubjectKeyIdentifier
2.5.29.15KeyUsage
2.5.29.16PrivateKeyUsage
2.5.29.17SubjectAlternativeName
2.5.29.18IssuerAlternativeName
2.5.29.19BasicConstraints
2.5.29.30NameConstraints
2.5.29.33PolicyMappings
2.5.29.35AuthorityKeyIdentifier
2.5.29.36PolicyConstraints
* * @param oid the Object Identifier value for the extension. * @return the DER-encoded octet string of the extension value or * null if it is not present. */ public byte[] getExtensionValue(String oid); }