1 /*
2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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
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7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 *
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 * X509Certificate cert = null;
89 * try (InputStream inStrm = new FileInputStream("DER-encoded-Cert")) {
90 * CertificateFactory cf = CertificateFactory.getInstance("X.509");
91 * cert = (X509Certificate)cf.generateCertificate(inStrm);
92 * }
93 *
94 * Set<String> critSet = cert.getCriticalExtensionOIDs();
95 * if (critSet != null && !critSet.isEmpty()) {
96 * System.out.println("Set of critical extensions:");
97 * for (String oid : critSet) {
98 * System.out.println(oid);
99 * }
100 * }
101 * }</pre>
102 * @return a Set (or an empty Set if none are marked critical) of
103 * the extension OID strings for extensions that are marked critical.
104 * If there are no extensions present at all, then this method returns
105 * null.
106 */
107 public Set<String> getCriticalExtensionOIDs();
108
109 /**
110 * Gets a Set of the OID strings for the extension(s) marked
111 * NON-CRITICAL in the certificate/CRL managed by the object
112 * implementing this interface.
113 *
114 * Here is sample code to get a Set of non-critical extensions from an
115 * X509CRL revoked certificate entry and print the OIDs:
116 * <pre><code>
117 * CertificateFactory cf = null;
118 * X509CRL crl = null;
119 * try (InputStream inStrm = new FileInputStream("DER-encoded-CRL")) {
120 * cf = CertificateFactory.getInstance("X.509");
121 * crl = (X509CRL)cf.generateCRL(inStrm);
122 * }<p>
123 *
124 * byte[] certData = <DER-encoded certificate data>
125 * ByteArrayInputStream bais = new ByteArrayInputStream(certData);
126 * X509Certificate cert = (X509Certificate)cf.generateCertificate(bais);
127 * X509CRLEntry badCert =
128 * crl.getRevokedCertificate(cert.getSerialNumber());<p>
129 *
130 * if (badCert != null) {
131 * Set<String> nonCritSet = badCert.getNonCriticalExtensionOIDs();<p>
132 * if (nonCritSet != null)
133 * for (String oid : nonCritSet) {
134 * System.out.println(oid);
135 * }
136 * }
137 * </code></pre>
138 *
139 * @return a Set (or an empty Set if none are marked non-critical) of
140 * the extension OID strings for extensions that are marked non-critical.
141 * If there are no extensions present at all, then this method returns
142 * null.
143 */
144 public Set<String> getNonCriticalExtensionOIDs();
145
146 /**
147 * Gets the DER-encoded OCTET string for the extension value
148 * (<em>extnValue</em>) identified by the passed-in <code>oid</code>
149 * String.
150 * The <code>oid</code> string is
151 * represented by a set of nonnegative whole numbers separated
152 * by periods.
153 *
154 * <p>For example:<br>
155 * <table border=groove summary="Examples of OIDs and extension names">
156 * <tr>
157 * <th>OID <em>(Object Identifier)</em></th>
158 * <th>Extension Name</th></tr>
159 * <tr><td>2.5.29.14</td>
160 * <td>SubjectKeyIdentifier</td></tr>
161 * <tr><td>2.5.29.15</td>
162 * <td>KeyUsage</td></tr>
163 * <tr><td>2.5.29.16</td>
164 * <td>PrivateKeyUsage</td></tr>
165 * <tr><td>2.5.29.17</td>
166 * <td>SubjectAlternativeName</td></tr>
167 * <tr><td>2.5.29.18</td>
168 * <td>IssuerAlternativeName</td></tr>
169 * <tr><td>2.5.29.19</td>
170 * <td>BasicConstraints</td></tr>
171 * <tr><td>2.5.29.30</td>
172 * <td>NameConstraints</td></tr>
173 * <tr><td>2.5.29.33</td>
174 * <td>PolicyMappings</td></tr>
175 * <tr><td>2.5.29.35</td>
176 * <td>AuthorityKeyIdentifier</td></tr>
177 * <tr><td>2.5.29.36</td>
178 * <td>PolicyConstraints</td></tr>
179 * </table>
180 *
181 * @param oid the Object Identifier value for the extension.
182 * @return the DER-encoded octet string of the extension value or
183 * null if it is not present.
184 */
185 public byte[] getExtensionValue(String oid);
186 }