1 /*
2 * Copyright (c) 2012, 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 package java.security.spec;
26
27 /**
28 * This immutable class specifies the set of parameters used for
29 * generating DSA parameters as specified in
30 * <a href="http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf">FIPS 186-3 Digital Signature Standard (DSS)</a>.
31 *
32 * @see AlgorithmParameterSpec
33 *
34 * @since 8
35 */
36 public final class DSAGenParameterSpec implements AlgorithmParameterSpec {
37
38 private final int pLen;
39 private final int qLen;
40 private final int seedLen;
41
42 /**
43 * Creates a domain parameter specification for DSA parameter
44 * generation using {@code primePLen} and {@code subprimeQLen}.
45 * The value of {@code subprimeQLen} is also used as the default
46 * length of the domain parameter seed in bits.
47 * @param primePLen the desired length of the prime P in bits.
48 * @param subprimeQLen the desired length of the sub-prime Q in bits.
49 * @exception IllegalArgumentException if {@code primePLen}
50 * or {@code subprimeQLen} is illegal per the specification of
51 * FIPS 186-3.
52 */
53 public DSAGenParameterSpec(int primePLen, int subprimeQLen) {
54 this(primePLen, subprimeQLen, subprimeQLen);
55 }
56
57 /**
58 * Creates a domain parameter specification for DSA parameter
59 * generation using {@code primePLen}, {@code subprimeQLen},
60 * and {@code seedLen}.
61 * @param primePLen the desired length of the prime P in bits.
62 * @param subprimeQLen the desired length of the sub-prime Q in bits.
63 * @param seedLen the desired length of the domain parameter seed in bits,
64 * shall be equal to or greater than {@code subprimeQLen}.
65 * @exception IllegalArgumentException if {@code primePLenLen},
66 * {@code subprimeQLen}, or {@code seedLen} is illegal per the
67 * specification of FIPS 186-3.
68 */
69 public DSAGenParameterSpec(int primePLen, int subprimeQLen, int seedLen) {
70 switch (primePLen) {
71 case 1024:
72 if (subprimeQLen != 160) {
73 throw new IllegalArgumentException
74 ("subprimeQLen must be 160 when primePLen=1024");
75 }
76 break;
77 case 2048:
78 if (subprimeQLen != 224 && subprimeQLen != 256) {
79 throw new IllegalArgumentException
80 ("subprimeQLen must be 224 or 256 when primePLen=2048");
81 }
82 break;
83 case 3072:
84 if (subprimeQLen != 256) {
85 throw new IllegalArgumentException
86 ("subprimeQLen must be 256 when primePLen=3072");
87 }
88 break;
89 default:
90 throw new IllegalArgumentException
91 ("primePLen must be 1024, 2048, or 3072");
92 }
93 if (seedLen < subprimeQLen) {
94 throw new IllegalArgumentException
95 ("seedLen must be equal to or greater than subprimeQLen");
96 }
97 this.pLen = primePLen;
98 this.qLen = subprimeQLen;
99 this.seedLen = seedLen;
100 }
101
102 /**
103 * Returns the desired length of the prime P of the
104 * to-be-generated DSA domain parameters in bits.
105 * @return the length of the prime P.
106 */
107 public int getPrimePLength() {
108 return pLen;
109 }
110
111 /**
112 * Returns the desired length of the sub-prime Q of the
113 * to-be-generated DSA domain parameters in bits.
114 * @return the length of the sub-prime Q.
115 */
116 public int getSubprimeQLength() {
117 return qLen;
118 }
119
120 /**
121 * Returns the desired length of the domain parameter seed in bits.
122 * @return the length of the domain parameter seed.
123 */
124 public int getSeedLength() {
125 return seedLen;
126 }
127 }