/* * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.crypto.spec; import java.math.BigInteger;import java.security.spec.AlgorithmParameterSpec; /** * This class specifies the set of parameters used with the Diffie-Hellman * algorithm, as specified in PKCS #3: <i>Diffie-Hellman Key-Agreement * Standard</i>. * * <p>A central authority generates parameters and gives them to the two * entities seeking to generate a secret key. The parameters are a prime * <code>p</code>, a base <code>g</code>, and optionally the length * in bits of the private value, <code>l</code>. * * <p>It is possible that more than one instance of parameters may be * generated by a given central authority, and that there may be more than * one central authority. Indeed, each individual may be its own central * authority, with different entities having different parameters. * * <p>Note that this class does not perform any validation on specified * parameters. Thus, the specified values are returned directly even * if they are null. * * @author Jan Luehe * * @see javax.crypto.KeyAgreement * @since 1.4 */public class DHParameterSpec implements AlgorithmParameterSpec {     // The prime modulus    private BigInteger p;     // The base generator    private BigInteger g;     // The size in bits of the random exponent (private value) (optional)    private int l;     /**     * Constructs a parameter set for Diffie-Hellman, using a prime modulus     * <code>p</code> and a base generator <code>g</code>.     *     * @param p the prime modulus     * @param g the base generator     */    public DHParameterSpec(BigInteger p, BigInteger g) {        this.p = p;        this.g = g;        this.l = 0;    }     /**     * Constructs a parameter set for Diffie-Hellman, using a prime modulus     * <code>p</code>, a base generator <code>g</code>,     * and the size in bits, <code>l</code>, of the random exponent     * (private value).     *     * @param p the prime modulus     * @param g the base generator     * @param l the size in bits of the random exponent (private value)     */    public DHParameterSpec(BigInteger p, BigInteger g, int l) {        this.p = p;        this.g = g;        this.l = l;    }     /**     * Returns the prime modulus <code>p</code>.     *     * @return the prime modulus <code>p</code>     */    public BigInteger getP() {        return this.p;    }     /**     * Returns the base generator <code>g</code>.     *     * @return the base generator <code>g</code>     */    public BigInteger getG() {        return this.g;    }     /**     * Returns the size in bits, <code>l</code>, of the random exponent     * (private value).     *     * @return the size in bits, <code>l</code>, of the random exponent     * (private value), or 0 if this size has not been set     */    public int getL() {        return this.l;    }}