1 /* 2 * Copyright (c) 1998, 2013, 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 java.security; 27 28 /** 29 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) 30 * for the {@code SecureRandom} class. 31 * All the abstract methods in this class must be implemented by each 32 * service provider who wishes to supply the implementation 33 * of a cryptographically strong pseudo-random number generator. 34 * 35 * 36 * @see SecureRandom 37 * @since 1.2 38 */ 39 40 public abstract class SecureRandomSpi implements java.io.Serializable { 41 42 private static final long serialVersionUID = -2991854161009191830L; 43 44 /** 45 * Reseeds this random object. The given seed supplements, rather than 46 * replaces, the existing seed. Thus, repeated calls are guaranteed 47 * never to reduce randomness. 48 * 49 * @param seed the seed. 50 */ engineSetSeed(byte[] seed)51 protected abstract void engineSetSeed(byte[] seed); 52 53 /** 54 * Generates a user-specified number of random bytes. 55 * 56 * <p> If a call to {@code engineSetSeed} had not occurred previously, 57 * the first call to this method forces this SecureRandom implementation 58 * to seed itself. This self-seeding will not occur if 59 * {@code engineSetSeed} was previously called. 60 * 61 * @param bytes the array to be filled in with random bytes. 62 */ engineNextBytes(byte[] bytes)63 protected abstract void engineNextBytes(byte[] bytes); 64 65 /** 66 * Returns the given number of seed bytes. This call may be used to 67 * seed other random number generators. 68 * 69 * @param numBytes the number of seed bytes to generate. 70 * 71 * @return the seed bytes. 72 */ engineGenerateSeed(int numBytes)73 protected abstract byte[] engineGenerateSeed(int numBytes); 74 } 75