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 }