001/* DHParameterSpec.java -- Parameters for Diffie-Hellman keys. 002 Copyright (C) 2004 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package javax.crypto.spec; 040 041import java.math.BigInteger; 042import 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 */ 059public 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}