1 /*
2 * Copyright (c) 1996, 2006, 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
6 * under the terms of the GNU General Public License version 2 only, as
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 *
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.security;
27
28 /**
29 * The Key interface is the top-level interface for all keys. It
30 * defines the functionality shared by all key objects. All keys
31 * have three characteristics:
32 *
33 * <UL>
34 *
35 * <LI>An Algorithm
36 *
37 * <P>This is the key algorithm for that key. The key algorithm is usually
38 * an encryption or asymmetric operation algorithm (such as DSA or
39 * RSA), which will work with those algorithms and with related
40 * algorithms (such as MD5 with RSA, SHA-1 with RSA, Raw DSA, etc.)
41 * The name of the algorithm of a key is obtained using the
42 * {@link #getAlgorithm() getAlgorithm} method.<P>
43 *
44 * <LI>An Encoded Form
45 *
46 * <P>This is an external encoded form for the key used when a standard
47 * representation of the key is needed outside the Java Virtual Machine,
48 * as when transmitting the key to some other party. The key
49 * is encoded according to a standard format (such as
50 * X.509 <code>SubjectPublicKeyInfo</code> or PKCS#8), and
51 * is returned using the {@link #getEncoded() getEncoded} method.
52 * Note: The syntax of the ASN.1 type <code>SubjectPublicKeyInfo</code>
53 * is defined as follows:
54 *
55 * <pre>
56 * SubjectPublicKeyInfo ::= SEQUENCE {
57 * algorithm AlgorithmIdentifier,
58 * subjectPublicKey BIT STRING }
59 *
60 * AlgorithmIdentifier ::= SEQUENCE {
61 * algorithm OBJECT IDENTIFIER,
62 * parameters ANY DEFINED BY algorithm OPTIONAL }
63 * </pre>
64 *
65 * For more information, see
66 * <a href="http://www.ietf.org/rfc/rfc3280.txt">RFC 3280:
67 * Internet X.509 Public Key Infrastructure Certificate and CRL Profile</a>.
68 * <P>
69 *
70 * <LI>A Format
71 *
72 * <P>This is the name of the format of the encoded key. It is returned
73 * by the {@link #getFormat() getFormat} method.<P>
74 *
75 * </UL>
76 *
77 * Keys are generally obtained through key generators, certificates,
78 * or various Identity classes used to manage keys.
79 * Keys may also be obtained from key specifications (transparent
80 * representations of the underlying key material) through the use of a key
81 * factory (see {@link KeyFactory}).
82 *
83 * <p> A Key should use KeyRep as its serialized representation.
84 * Note that a serialized Key may contain sensitive information
85 * which should not be exposed in untrusted environments. See the
86 * <a href="../../../platform/serialization/spec/security.html">
87 * Security Appendix</a>
88 * of the Serialization Specification for more information.
89 *
90 * @see PublicKey
91 * @see PrivateKey
92 * @see KeyPair
93 * @see KeyPairGenerator
94 * @see KeyFactory
95 * @see KeyRep
96 * @see java.security.spec.KeySpec
97 * @see Identity
98 * @see Signer
99 *
100 * @author Benjamin Renaud
101 */
102
103 public interface Key extends java.io.Serializable {
104
105 // Declare serialVersionUID to be compatible with JDK1.1
106
107 /**
108 * The class fingerprint that is set to indicate
109 * serialization compatibility with a previous
110 * version of the class.
111 */
112 static final long serialVersionUID = 6603384152749567654L;
113
114 /**
115 * Returns the standard algorithm name for this key. For
116 * example, "DSA" would indicate that this key is a DSA key.
117 * See Appendix A in the <a href=
118 * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA">
119 * Java Cryptography Architecture API Specification & Reference </a>
120 * for information about standard algorithm names.
121 *
122 * @return the name of the algorithm associated with this key.
123 */
124 public String getAlgorithm();
125
126 /**
127 * Returns the name of the primary encoding format of this key,
128 * or null if this key does not support encoding.
129 * The primary encoding format is
130 * named in terms of the appropriate ASN.1 data format, if an
131 * ASN.1 specification for this key exists.
132 * For example, the name of the ASN.1 data format for public
133 * keys is <I>SubjectPublicKeyInfo</I>, as
134 * defined by the X.509 standard; in this case, the returned format is
135 * <code>"X.509"</code>. Similarly,
136 * the name of the ASN.1 data format for private keys is
137 * <I>PrivateKeyInfo</I>,
138 * as defined by the PKCS #8 standard; in this case, the returned format is
139 * <code>"PKCS#8"</code>.
140 *
141 * @return the primary encoding format of the key.
142 */
143 public String getFormat();
144
145 /**
146 * Returns the key in its primary encoding format, or null
147 * if this key does not support encoding.
148 *
149 * @return the encoded key, or null if the key does not support
150 * encoding.
151 */
152 public byte[] getEncoded();
153 }