1 /*
2 * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.security.cert;
27
28 import java.util.Set;
29
30 /**
31 * Interface for an X.509 extension.
32 *
33 * <p>The extensions defined for X.509 v3
34 * {@link X509Certificate Certificates} and v2
35 * {@link X509CRL CRLs} (Certificate Revocation
36 * Lists) provide methods
37 * for associating additional attributes with users or public keys,
38 * for managing the certification hierarchy, and for managing CRL
39 * distribution. The X.509 extensions format also allows communities
40 * to define private extensions to carry information unique to those
41 * communities.
42 *
43 * <p>Each extension in a certificate/CRL may be designated as
44 * critical or non-critical. A certificate/CRL-using system (an application
45 * validating a certificate/CRL) must reject the certificate/CRL if it
46 * encounters a critical extension it does not recognize. A non-critical
47 * extension may be ignored if it is not recognized.
48 * <p>
49 * The ASN.1 definition for this is:
50 * <pre>
51 * Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
52 *
53 * Extension ::= SEQUENCE {
54 * extnId OBJECT IDENTIFIER,
55 * critical BOOLEAN DEFAULT FALSE,
56 * extnValue OCTET STRING
57 * -- contains a DER encoding of a value
58 * -- of the type registered for use with
59 * -- the extnId object identifier value
60 * }
61 * </pre>
62 * Since not all extensions are known, the <code>getExtensionValue</code>
63 * method returns the DER-encoded OCTET STRING of the
64 * extension value (i.e., the <code>extnValue</code>). This can then
65 * be handled by a <em>Class</em> that understands the extension.
66 *
67 * @author Hemma Prafullchandra
68 */
69
70 public interface X509Extension {
71
72 /**
73 * Check if there is a critical extension that is not supported.
74 *
75 * @return <tt>true</tt> if a critical extension is found that is
76 * not supported, otherwise <tt>false</tt>.
77 */
78 public boolean hasUnsupportedCriticalExtension();
79
80 /**
81 * Gets a Set of the OID strings for the extension(s) marked
82 * CRITICAL in the certificate/CRL managed by the object
83 * implementing this interface.
84 *
85 * Here is sample code to get a Set of critical extensions from an
86 * X509Certificate and print the OIDs:
87 * <pre><code>
88 * InputStream inStrm = null;
89 * X509Certificate cert = null;
90 * try {
91 * inStrm = new FileInputStream("DER-encoded-Cert");
92 * CertificateFactory cf = CertificateFactory.getInstance("X.509");
93 * cert = (X509Certificate)cf.generateCertificate(inStrm);
94 * } finally {
95 * if (inStrm != null) {
96 * inStrm.close();
97 * }
98 * }<p>
99 *
100 * Set<String> critSet = cert.getCriticalExtensionOIDs();
101 * if (critSet != null && !critSet.isEmpty()) {
102 * System.out.println("Set of critical extensions:");
103 * for (String oid : critSet) {
104 * System.out.println(oid);
105 * }
106 * }
107 * </code></pre>
108 * @return a Set (or an empty Set if none are marked critical) of
109 * the extension OID strings for extensions that are marked critical.
110 * If there are no extensions present at all, then this method returns
111 * null.
112 */
113 public Set<String> getCriticalExtensionOIDs();
114
115 /**
116 * Gets a Set of the OID strings for the extension(s) marked
117 * NON-CRITICAL in the certificate/CRL managed by the object
118 * implementing this interface.
119 *
120 * Here is sample code to get a Set of non-critical extensions from an
121 * X509CRL revoked certificate entry and print the OIDs:
122 * <pre><code>
123 * InputStream inStrm = null;
124 * CertificateFactory cf = null;
125 * X509CRL crl = null;
126 * try {
127 * inStrm = new FileInputStream("DER-encoded-CRL");
128 * cf = CertificateFactory.getInstance("X.509");
129 * crl = (X509CRL)cf.generateCRL(inStrm);
130 * } finally {
131 * if (inStrm != null) {
132 * inStrm.close();
133 * }
134 * }<p>
135 *
136 * byte[] certData = <DER-encoded certificate data>
137 * ByteArrayInputStream bais = new ByteArrayInputStream(certData);
138 * X509Certificate cert = (X509Certificate)cf.generateCertificate(bais);
139 * bais.close();
140 * X509CRLEntry badCert =
141 * crl.getRevokedCertificate(cert.getSerialNumber());<p>
142 *
143 * if (badCert != null) {
144 * Set<String> nonCritSet = badCert.getNonCriticalExtensionOIDs();<p>
145 * if (nonCritSet != null)
146 * for (String oid : nonCritSet) {
147 * System.out.println(oid);
148 * }
149 * }
150 * </code></pre>
151 *
152 * @return a Set (or an empty Set if none are marked non-critical) of
153 * the extension OID strings for extensions that are marked non-critical.
154 * If there are no extensions present at all, then this method returns
155 * null.
156 */
157 public Set<String> getNonCriticalExtensionOIDs();
158
159 /**
160 * Gets the DER-encoded OCTET string for the extension value
161 * (<em>extnValue</em>) identified by the passed-in <code>oid</code>
162 * String.
163 * The <code>oid</code> string is
164 * represented by a set of nonnegative whole numbers separated
165 * by periods.
166 *
167 * <p>For example:<br>
168 * <table border=groove summary="Examples of OIDs and extension names">
169 * <tr>
170 * <th>OID <em>(Object Identifier)</em></th>
171 * <th>Extension Name</th></tr>
172 * <tr><td>2.5.29.14</td>
173 * <td>SubjectKeyIdentifier</td></tr>
174 * <tr><td>2.5.29.15</td>
175 * <td>KeyUsage</td></tr>
176 * <tr><td>2.5.29.16</td>
177 * <td>PrivateKeyUsage</td></tr>
178 * <tr><td>2.5.29.17</td>
179 * <td>SubjectAlternativeName</td></tr>
180 * <tr><td>2.5.29.18</td>
181 * <td>IssuerAlternativeName</td></tr>
182 * <tr><td>2.5.29.19</td>
183 * <td>BasicConstraints</td></tr>
184 * <tr><td>2.5.29.30</td>
185 * <td>NameConstraints</td></tr>
186 * <tr><td>2.5.29.33</td>
187 * <td>PolicyMappings</td></tr>
188 * <tr><td>2.5.29.35</td>
189 * <td>AuthorityKeyIdentifier</td></tr>
190 * <tr><td>2.5.29.36</td>
191 * <td>PolicyConstraints</td></tr>
192 * </table>
193 *
194 * @param oid the Object Identifier value for the extension.
195 * @return the DER-encoded octet string of the extension value or
196 * null if it is not present.
197 */
198 public byte[] getExtensionValue(String oid);
199 }
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