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Java > Open Source Codes > java > security > cert > X509Extension


1 /*
2  * @(#)X509Extension.java 1.22 03/12/19
3  *
4  * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5  * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6  */
7
8 package java.security.cert;
9
10 import java.util.Set JavaDoc;
11
12 /**
13  * Interface for an X.509 extension.
14  *
15  * <p>The extensions defined for X.509 v3
16  * {@link X509Certificate Certificates} and v2
17  * {@link X509CRL CRLs} (Certificate Revocation
18  * Lists) provide methods
19  * for associating additional attributes with users or public keys,
20  * for managing the certification hierarchy, and for managing CRL
21  * distribution. The X.509 extensions format also allows communities
22  * to define private extensions to carry information unique to those
23  * communities.
24  *
25  * <p>Each extension in a certificate/CRL may be designated as
26  * critical or non-critical. A certificate/CRL-using system (an application
27  * validating a certificate/CRL) must reject the certificate/CRL if it
28  * encounters a critical extension it does not recognize. A non-critical
29  * extension may be ignored if it is not recognized.
30  * <p>
31  * The ASN.1 definition for this is:
32  * <pre>
33  * Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
34  *
35  * Extension ::= SEQUENCE {
36  * extnId OBJECT IDENTIFIER,
37  * critical BOOLEAN DEFAULT FALSE,
38  * extnValue OCTET STRING
39  * -- contains a DER encoding of a value
40  * -- of the type registered for use with
41  * -- the extnId object identifier value
42  * }
43  * </pre>
44  * Since not all extensions are known, the <code>getExtensionValue</code>
45  * method returns the DER-encoded OCTET STRING of the
46  * extension value (i.e., the <code>extnValue</code>). This can then
47  * be handled by a <em>Class</em> that understands the extension.
48  *
49  * @author Hemma Prafullchandra
50  * @version 1.22 03/12/19
51  */
52
53 public interface X509Extension {
54
55     /**
56      * Check if there is a critical extension that is not supported.
57      *
58      * @return <tt>true</tt> if a critical extension is found that is
59      * not supported, otherwise <tt>false</tt>.
60      */
61     public boolean hasUnsupportedCriticalExtension();
62
63     /**
64      * Gets a Set of the OID strings for the extension(s) marked
65      * CRITICAL in the certificate/CRL managed by the object
66      * implementing this interface.
67      *
68      * Here is sample code to get a Set of critical extensions from an
69      * X509Certificate and print the OIDs:
70      * <pre><code>
71      * InputStream inStrm = new FileInputStream("DER-encoded-Cert");
72      * CertificateFactory cf = CertificateFactory.getInstance("X.509");
73      * X509Certificate cert = (X509Certificate)cf.generateCertificate(inStrm);
74      * inStrm.close();<p>
75      *
76      * Set critSet = cert.getCriticalExtensionOIDs();
77      * if (critSet != null && !critSet.isEmpty()) {
78      * System.out.println("Set of critical extensions:");
79      * for (Iterator i = critSet.iterator(); i.hasNext();) {
80      * String oid = (String)i.next();
81      * System.out.println(oid);
82      * }
83      * }
84      * </code></pre>
85      * @return a Set (or an empty Set if none are marked critical) of
86      * the extension OID strings for extensions that are marked critical.
87      * If there are no extensions present at all, then this method returns
88      * null.
89      */
90     public Set JavaDoc<String JavaDoc> getCriticalExtensionOIDs();
91
92     /**
93      * Gets a Set of the OID strings for the extension(s) marked
94      * NON-CRITICAL in the certificate/CRL managed by the object
95      * implementing this interface.
96      *
97      * Here is sample code to get a Set of non-critical extensions from an
98      * X509CRL revoked certificate entry and print the OIDs:
99      * <pre><code>
100      * InputStream inStrm = new FileInputStream("DER-encoded-CRL");
101      * CertificateFactory cf = CertificateFactory.getInstance("X.509");
102      * X509CRL crl = (X509CRL)cf.generateCRL(inStrm);
103      * inStrm.close();<p>
104      *
105      * byte[] certData = &lt;DER-encoded certificate data&gt;
106      * ByteArrayInputStream bais = new ByteArrayInputStream(certData);
107      * X509Certificate cert = (X509Certificate)cf.generateCertificate(bais);
108      * bais.close();
109      * X509CRLEntry badCert =
110      * crl.getRevokedCertificate(cert.getSerialNumber());<p>
111      *
112      * if (badCert != null) {
113      * Set nonCritSet = badCert.getNonCriticalExtensionOIDs();<p>
114      * if (nonCritSet != null)
115      * for (Iterator i = nonCritSet.iterator(); i.hasNext();) {
116      * String oid = (String)i.next();
117      * System.out.println(oid);
118      * }
119      * }
120      * </code></pre>
121      *
122      * @return a Set (or an empty Set if none are marked non-critical) of
123      * the extension OID strings for extensions that are marked non-critical.
124      * If there are no extensions present at all, then this method returns
125      * null.
126      */
127     public Set JavaDoc<String JavaDoc> getNonCriticalExtensionOIDs();
128
129     /**
130      * Gets the DER-encoded OCTET string for the extension value
131      * (<em>extnValue</em>) identified by the passed-in <code>oid</code>
132      * String.
133      * The <code>oid</code> string is
134      * represented by a set of nonnegative whole numbers separated
135      * by periods.
136      *
137      * <p>For example:<br>
138      * <table border=groove summary="Examples of OIDs and extension names">
139      * <tr>
140      * <th>OID <em>(Object Identifier)</em></th>
141      * <th>Extension Name</th></tr>
142      * <tr><td>2.5.29.14</td>
143      * <td>SubjectKeyIdentifier</td></tr>
144      * <tr><td>2.5.29.15</td>
145      * <td>KeyUsage</td></tr>
146      * <tr><td>2.5.29.16</td>
147      * <td>PrivateKeyUsage</td></tr>
148      * <tr><td>2.5.29.17</td>
149      * <td>SubjectAlternativeName</td></tr>
150      * <tr><td>2.5.29.18</td>
151      * <td>IssuerAlternativeName</td></tr>
152      * <tr><td>2.5.29.19</td>
153      * <td>BasicConstraints</td></tr>
154      * <tr><td>2.5.29.30</td>
155      * <td>NameConstraints</td></tr>
156      * <tr><td>2.5.29.33</td>
157      * <td>PolicyMappings</td></tr>
158      * <tr><td>2.5.29.35</td>
159      * <td>AuthorityKeyIdentifier</td></tr>
160      * <tr><td>2.5.29.36</td>
161      * <td>PolicyConstraints</td></tr>
162      * </table>
163      *
164      * @param oid the Object Identifier value for the extension.
165      * @return the DER-encoded octet string of the extension value or
166      * null if it is not present.
167      */
168     public byte[] getExtensionValue(String JavaDoc oid);
169 }
170
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