001 /* DHParameterSpec.java -- Parameters for Diffie-Hellman keys.
002 Copyright (C) 2004 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package javax.crypto.spec;
040
041 import java.math.BigInteger;
042 import java.security.spec.AlgorithmParameterSpec;
043
044 /**
045 * The base set of parameters necessary to perform Diffie-Hellman key
046 * exchange. Each party in the key exchange shares these parameters.
047 *
048 * <p>Each set of parameters consists of a <i>base generator</i>
049 * <code>g</code>, a <i>prime modulus</i> <code>p</code>, and an
050 * optional length, in bits, of the private exponent.
051 *
052 * <p>See <a href="http://www.rsasecurity.com/rsalabs/pkcs/pkcs-3/">PKCS
053 * #3 - Diffie-Hellman Key Agreement Standard</a> for more information.
054 *
055 * @author Casey Marshall (csm@gnu.org)
056 * @since 1.4
057 * @see javax.crypto.KeyAgreement
058 */
059 public class DHParameterSpec implements AlgorithmParameterSpec
060 {
061
062 // Variables.
063 // ------------------------------------------------------------------------
064
065 /** The base generator g. */
066 private BigInteger g;
067
068 /** The prime modulus p. */
069 private BigInteger p;
070
071 /** The length, in bits, of the private exponent. */
072 private int l;
073
074 // Constructors.
075 // ------------------------------------------------------------------------
076
077 /**
078 * Create a new set of Diffie-Hellman parameters.
079 *
080 * @param p The prime modulus.
081 * @param g The base generator.
082 */
083 public DHParameterSpec(BigInteger p, BigInteger g)
084 {
085 this(p, g, 0);
086 }
087
088 /**
089 * Create a new set of Diffie-Hellman parameters.
090 *
091 * @param p The prime modulus.
092 * @param g The base generator.
093 * @param l The size of the private exponent, in bits.
094 */
095 public DHParameterSpec(BigInteger p, BigInteger g, int l)
096 {
097 this.p = p;
098 this.g = g;
099 this.l = l;
100 }
101
102 // Instance methods.
103 // ------------------------------------------------------------------------
104
105 /**
106 * Get the base generator, <i>g</i>.
107 *
108 * @return The base generator <i>g</i>.
109 */
110 public BigInteger getG()
111 {
112 return g;
113 }
114
115 /**
116 * Get the length of the private exponent, in bits.
117 *
118 * @return The length of the private exponent, in bits, or 0 if this
119 * has not been explicitly set.
120 */
121 public int getL()
122 {
123 return l;
124 }
125
126 /**
127 * Get the prime modulus, <i>p</i>.
128 *
129 * @return The prime modulus, <i>p</i>.
130 */
131 public BigInteger getP()
132 {
133 return p;
134 }
135 }