Java tutorial
/* * 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; } }