/* * Copyright (c) 1999, 2009, 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 com.sun.crypto.provider; import java.security.SecureRandom;import java.security.InvalidParameterException;import java.security.InvalidAlgorithmParameterException;import java.security.spec.AlgorithmParameterSpec;import javax.crypto.KeyGeneratorSpi;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec; /** * This class generates a secret key for use with the HMAC-MD5 algorithm. * * @author Jan Luehe * */ public final class HmacMD5KeyGenerator extends KeyGeneratorSpi {     private SecureRandom random = null;    private int keysize = 64; // default keysize (in number of bytes)     /**     * Empty constructor     */    public HmacMD5KeyGenerator() {    }     /**     * Initializes this key generator.     *     * @param random the source of randomness for this generator     */    protected void engineInit(SecureRandom random) {        this.random = random;    }     /**     * Initializes this key generator with the specified parameter     * set and a user-provided source of randomness.     *     * @param params the key generation parameters     * @param random the source of randomness for this key generator     *     * @exception InvalidAlgorithmParameterException if <code>params</code> is     * inappropriate for this key generator     */    protected void engineInit(AlgorithmParameterSpec params,                              SecureRandom random)        throws InvalidAlgorithmParameterException    {        throw new InvalidAlgorithmParameterException            ("HMAC-MD5 key generation does not take any parameters");    }     /**     * Initializes this key generator for a certain keysize, using the given     * source of randomness.     *     * @param keysize the keysize. This is an algorithm-specific     * metric specified in number of bits.     * @param random the source of randomness for this key generator     */    protected void engineInit(int keysize, SecureRandom random) {        this.keysize = (keysize+7) / 8;        this.engineInit(random);    }     /**     * Generates an HMAC-MD5 key.     *     * @return the new HMAC-MD5 key     */    protected SecretKey engineGenerateKey() {        if (this.random == null) {            this.random = SunJCE.RANDOM;        }         byte[] keyBytes = new byte[this.keysize];        this.random.nextBytes(keyBytes);         return new SecretKeySpec(keyBytes, "HmacMD5");    }}