1 /* 2 * Copyright (c) 1997, 2007, 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 26 package javax.crypto.spec; 27 28 import java.math.BigInteger; 29 import java.security.spec.AlgorithmParameterSpec; 30 31 /** 32 * This class specifies the set of parameters used with the Diffie-Hellman 33 * algorithm, as specified in PKCS #3: <i>Diffie-Hellman Key-Agreement 34 * Standard</i>. 35 * 36 * <p>A central authority generates parameters and gives them to the two 37 * entities seeking to generate a secret key. The parameters are a prime 38 * <code>p</code>, a base <code>g</code>, and optionally the length 39 * in bits of the private value, <code>l</code>. 40 * 41 * <p>It is possible that more than one instance of parameters may be 42 * generated by a given central authority, and that there may be more than 43 * one central authority. Indeed, each individual may be its own central 44 * authority, with different entities having different parameters. 45 * 46 * <p>Note that this class does not perform any validation on specified 47 * parameters. Thus, the specified values are returned directly even 48 * if they are null. 49 * 50 * @author Jan Luehe 51 * 52 * @see javax.crypto.KeyAgreement 53 * @since 1.4 54 */ 55 public class DHParameterSpec implements AlgorithmParameterSpec { 56 57 // The prime modulus 58 private BigInteger p; 59 60 // The base generator 61 private BigInteger g; 62 63 // The size in bits of the random exponent (private value) (optional) 64 private int l; 65 66 /** 67 * Constructs a parameter set for Diffie-Hellman, using a prime modulus 68 * <code>p</code> and a base generator <code>g</code>. 69 * 70 * @param p the prime modulus 71 * @param g the base generator 72 */ DHParameterSpec(BigInteger p, BigInteger g)73 public DHParameterSpec(BigInteger p, BigInteger g) { 74 this.p = p; 75 this.g = g; 76 this.l = 0; 77 } 78 79 /** 80 * Constructs a parameter set for Diffie-Hellman, using a prime modulus 81 * <code>p</code>, a base generator <code>g</code>, 82 * and the size in bits, <code>l</code>, of the random exponent 83 * (private value). 84 * 85 * @param p the prime modulus 86 * @param g the base generator 87 * @param l the size in bits of the random exponent (private value) 88 */ DHParameterSpec(BigInteger p, BigInteger g, int l)89 public DHParameterSpec(BigInteger p, BigInteger g, int l) { 90 this.p = p; 91 this.g = g; 92 this.l = l; 93 } 94 95 /** 96 * Returns the prime modulus <code>p</code>. 97 * 98 * @return the prime modulus <code>p</code> 99 */ getP()100 public BigInteger getP() { 101 return this.p; 102 } 103 104 /** 105 * Returns the base generator <code>g</code>. 106 * 107 * @return the base generator <code>g</code> 108 */ getG()109 public BigInteger getG() { 110 return this.g; 111 } 112 113 /** 114 * Returns the size in bits, <code>l</code>, of the random exponent 115 * (private value). 116 * 117 * @return the size in bits, <code>l</code>, of the random exponent 118 * (private value), or 0 if this size has not been set 119 */ getL()120 public int getL() { 121 return this.l; 122 } 123 } 124