1 /*
2 * Copyright (c) 1997, 2019, 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.interfaces;
27
28 import java.security.*;
29
30 /**
31 * An interface to an object capable of generating DSA key pairs.
32 *
33 * <p>The {@code initialize} methods may each be called any number
34 * of times. If no {@code initialize} method is called on a
35 * DSAKeyPairGenerator, each provider that implements this interface
36 * should supply (and document) a default initialization. Note that
37 * defaults may vary across different providers. Additionally, the default
38 * value for a provider may change in a future version. Therefore, it is
39 * recommended to explicitly initialize the DSAKeyPairGenerator instead
40 * of relying on provider-specific defaults.
41 *
42 * <p>Users wishing to indicate DSA-specific parameters, and to generate a key
43 * pair suitable for use with the DSA algorithm typically
44 *
45 * <ol>
46 *
47 * <li>Get a key pair generator for the DSA algorithm by calling the
48 * KeyPairGenerator {@code getInstance} method with "DSA"
49 * as its argument.
50 *
51 * <li>Check if the returned key pair generator is an instance of
52 * DSAKeyPairGenerator before casting the result to a DSAKeyPairGenerator
53 * and calling one of the {@code initialize} methods from this
54 * DSAKeyPairGenerator interface.
55 *
56 * <li>Generate a key pair by calling the {@code generateKeyPair}
57 * method of the KeyPairGenerator class.
58 *
59 * </ol>
60 *
61 * <p>Note: it is not always necessary to do algorithm-specific
62 * initialization for a DSA key pair generator. That is, it is not always
63 * necessary to call an {@code initialize} method in this interface.
64 * Algorithm-independent initialization using the {@code initialize} method
65 * in the KeyPairGenerator
66 * interface is all that is needed when you accept defaults for algorithm-specific
67 * parameters.
68 *
69 * <p>Note: Some earlier implementations of this interface may not support
70 * larger values of DSA parameters such as 3072-bit.
71 *
72 * @since 1.1
73 * @see java.security.KeyPairGenerator
74 */
75 public interface DSAKeyPairGenerator {
76
77 /**
78 * Initializes the key pair generator using the DSA family parameters
79 * (p,q and g) and an optional SecureRandom bit source. If a
80 * SecureRandom bit source is needed but not supplied, i.e. null, a
81 * default SecureRandom instance will be used.
82 *
83 * @param params the parameters to use to generate the keys.
84 *
85 * @param random the random bit source to use to generate key bits;
86 * can be null.
87 *
88 * @throws InvalidParameterException if the {@code params}
89 * value is invalid, null, or unsupported.
90 */
91 public void initialize(DSAParams params, SecureRandom random)
92 throws InvalidParameterException;
93
94 /**
95 * Initializes the key pair generator for a given modulus length
96 * (instead of parameters), and an optional SecureRandom bit source.
97 * If a SecureRandom bit source is needed but not supplied, i.e.
98 * null, a default SecureRandom instance will be used.
99 *
100 * <p>If {@code genParams} is true, this method generates new
101 * p, q and g parameters. If it is false, the method uses precomputed
102 * parameters for the modulus length requested. If there are no
103 * precomputed parameters for that modulus length, an exception will be
104 * thrown.
105 *
106 * @param modlen the modulus length in bits. Valid values are any
107 * multiple of 64 between 512 and 1024, inclusive, 2048, and 3072.
108 *
109 * @param random the random bit source to use to generate key bits;
110 * can be null.
111 *
112 * @param genParams whether or not to generate new parameters for
113 * the modulus length requested.
114 *
115 * @throws InvalidParameterException if {@code modlen} is
116 * invalid, or unsupported, or if {@code genParams} is false and there
117 * are no precomputed parameters for the requested modulus length.
118 */
119 public void initialize(int modlen, boolean genParams, SecureRandom random)
120 throws InvalidParameterException;
121 }