1 /*
2 * Copyright (c) 1996, 2017, 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.
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} or PKCS#8), and
51 * is returned using the {@link #getEncoded() getEncoded} method.
52 * Note: The syntax of the ASN.1 type {@code SubjectPublicKeyInfo}
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://tools.ietf.org/html/rfc5280">RFC 5280:
67 * Internet X.509 Public Key Infrastructure Certificate and CRL Profile</a>.
68 *
69 * <LI>A Format
70 *
71 * <P>This is the name of the format of the encoded key. It is returned
72 * by the {@link #getFormat() getFormat} method.
73 *
74 * </UL>
75 *
76 * Keys are generally obtained through key generators, certificates,
77 * or various Identity classes used to manage keys.
78 * Keys may also be obtained from key specifications (transparent
79 * representations of the underlying key material) through the use of a key
80 * factory (see {@link KeyFactory}).
81 *
82 * <p> A Key should use KeyRep as its serialized representation.
83 * Note that a serialized Key may contain sensitive information
84 * which should not be exposed in untrusted environments. See the
85 * <a href="{@docRoot}/../specs/serialization/security.html">
86 * Security Appendix</a>
87 * of the Serialization Specification for more information.
88 *
89 * @see PublicKey
90 * @see PrivateKey
91 * @see KeyPair
92 * @see KeyPairGenerator
93 * @see KeyFactory
94 * @see KeyRep
95 * @see java.security.spec.KeySpec
96 * @see Identity
97 * @see Signer
98 *
99 * @author Benjamin Renaud
100 */
101
102 public interface Key extends java.io.Serializable {
103
104 // Declare serialVersionUID to be compatible with JDK1.1
105
106 /**
107 * The class fingerprint that is set to indicate
108 * serialization compatibility with a previous
109 * version of the class.
110 */
111 static final long serialVersionUID = 6603384152749567654L;
112
113 /**
114 * Returns the standard algorithm name for this key. For
115 * example, "DSA" would indicate that this key is a DSA key.
116 * See Appendix A in the <a href=
117 * "../../../technotes/guides/security/crypto/CryptoSpec.html#AppA">
118 * Java Cryptography Architecture API Specification & Reference </a>
119 * for information about standard algorithm names.
120 *
121 * @return the name of the algorithm associated with this key.
122 */
123 public String getAlgorithm();
124
125 /**
126 * Returns the name of the primary encoding format of this key,
127 * or null if this key does not support encoding.
128 * The primary encoding format is
129 * named in terms of the appropriate ASN.1 data format, if an
130 * ASN.1 specification for this key exists.
131 * For example, the name of the ASN.1 data format for public
132 * keys is <I>SubjectPublicKeyInfo</I>, as
133 * defined by the X.509 standard; in this case, the returned format is
134 * {@code "X.509"}. Similarly,
135 * the name of the ASN.1 data format for private keys is
136 * <I>PrivateKeyInfo</I>,
137 * as defined by the PKCS #8 standard; in this case, the returned format is
138 * {@code "PKCS#8"}.
139 *
140 * @return the primary encoding format of the key.
141 */
142 public String getFormat();
143
144 /**
145 * Returns the key in its primary encoding format, or null
146 * if this key does not support encoding.
147 *
148 * @return the encoded key, or null if the key does not support
149 * encoding.
150 */
151 public byte[] getEncoded();
152 }