1 /*
2 * Copyright 1997-2005 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any 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</code> methods may each be called any number
34 * of times. If no <code>initialize</code> method is called on a
35 * DSAKeyPairGenerator, the default is to generate 1024-bit keys, using
36 * precomputed p, q and g parameters and an instance of SecureRandom as
37 * the random bit source.
38 *
39 * <p>Users wishing to indicate DSA-specific parameters, and to generate a key
40 * pair suitable for use with the DSA algorithm typically
41 *
42 * <ol>
43 *
44 * <li>Get a key pair generator for the DSA algorithm by calling the
45 * KeyPairGenerator <code>getInstance</code> method with "DSA"
46 * as its argument.<p>
47 *
48 * <li>Initialize the generator by casting the result to a DSAKeyPairGenerator
49 * and calling one of the
50 * <code>initialize</code> methods from this DSAKeyPairGenerator interface.<p>
51 *
52 * <li>Generate a key pair by calling the <code>generateKeyPair</code>
53 * method from the KeyPairGenerator class.
54 *
55 * </ol>
56 *
57 * <p>Note: it is not always necessary to do do algorithm-specific
58 * initialization for a DSA key pair generator. That is, it is not always
59 * necessary to call an <code>initialize</code> method in this interface.
60 * Algorithm-independent initialization using the <code>initialize</code> method
61 * in the KeyPairGenerator
62 * interface is all that is needed when you accept defaults for algorithm-specific
63 * parameters.
64 *
65 * @see java.security.KeyPairGenerator
66 */
67 public interface DSAKeyPairGenerator {
68
69 /**
70 * Initializes the key pair generator using the DSA family parameters
71 * (p,q and g) and an optional SecureRandom bit source. If a
72 * SecureRandom bit source is needed but not supplied, i.e. null, a
73 * default SecureRandom instance will be used.
74 *
75 * @param params the parameters to use to generate the keys.
76 *
77 * @param random the random bit source to use to generate key bits;
78 * can be null.
79 *
80 * @exception InvalidParameterException if the <code>params</code>
81 * value is invalid or null.
82 */
83 public void initialize(DSAParams params, SecureRandom random)
84 throws InvalidParameterException;
85
86 /**
87 * Initializes the key pair generator for a given modulus length
88 * (instead of parameters), and an optional SecureRandom bit source.
89 * If a SecureRandom bit source is needed but not supplied, i.e.
90 * null, a default SecureRandom instance will be used.
91 *
92 * <p>If <code>genParams</code> is true, this method generates new
93 * p, q and g parameters. If it is false, the method uses precomputed
94 * parameters for the modulus length requested. If there are no
95 * precomputed parameters for that modulus length, an exception will be
96 * thrown. It is guaranteed that there will always be
97 * default parameters for modulus lengths of 512 and 1024 bits.
98 *
99 * @param modlen the modulus length in bits. Valid values are any
100 * multiple of 8 between 512 and 1024, inclusive.
101 *
102 * @param random the random bit source to use to generate key bits;
103 * can be null.
104 *
105 * @param genParams whether or not to generate new parameters for
106 * the modulus length requested.
107 *
108 * @exception InvalidParameterException if <code>modlen</code> is not
109 * between 512 and 1024, or if <code>genParams</code> is false and
110 * there are no precomputed parameters for the requested modulus
111 * length.
112 */
113 public void initialize(int modlen, boolean genParams, SecureRandom random)
114 throws InvalidParameterException;
115 }
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