/* * Copyright (c) 1998, 2005, 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 java.security; /** * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) * for the <code>SecureRandom</code> class. * All the abstract methods in this class must be implemented by each * service provider who wishes to supply the implementation * of a cryptographically strong pseudo-random number generator. * * * @see SecureRandom * @since 1.2 */ public abstract class SecureRandomSpi implements java.io.Serializable {     private static final long serialVersionUID = -2991854161009191830L;     /**     * Reseeds this random object. The given seed supplements, rather than     * replaces, the existing seed. Thus, repeated calls are guaranteed     * never to reduce randomness.     *     * @param seed the seed.     */    protected abstract void engineSetSeed(byte[] seed);     /**     * Generates a user-specified number of random bytes.     *     * <p> If a call to <code>engineSetSeed</code> had not occurred previously,     * the first call to this method forces this SecureRandom implementation     * to seed itself.  This self-seeding will not occur if     * <code>engineSetSeed</code> was previously called.     *     * @param bytes the array to be filled in with random bytes.     */    protected abstract void engineNextBytes(byte[] bytes);     /**     * Returns the given number of seed bytes.  This call may be used to     * seed other random number generators.     *     * @param numBytes the number of seed bytes to generate.     *     * @return the seed bytes.     */     protected abstract byte[] engineGenerateSeed(int numBytes);}