| /* SecureRandomAdapter.java -- |
| Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.security.jce.prng; |
| |
| import gnu.java.security.prng.LimitReachedException; |
| import gnu.java.security.prng.MDGenerator; |
| |
| import java.security.SecureRandomSpi; |
| import java.util.Collections; |
| |
| /** |
| * The implementation of a generic {@link java.security.SecureRandom} adapter |
| * class to wrap GNU PRNG instances based on Message Digest algorithms. |
| * <p> |
| * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) for |
| * the {@link java.security.SecureRandom} class, which provides the |
| * functionality of a cryptographically strong pseudo-random number generator. |
| * <p> |
| * All the abstract methods in the {@link SecureRandomSpi} class are implemented |
| * by this class and all its sub-classes. |
| */ |
| abstract class SecureRandomAdapter |
| extends SecureRandomSpi |
| { |
| /** Our underlying prng instance. */ |
| private MDGenerator adaptee = new MDGenerator(); |
| |
| /** The name of the message digest algorithm used by the adaptee. */ |
| private String mdName; |
| |
| /** |
| * Trivial protected constructor. |
| * |
| * @param mdName the canonical name of the underlying hash algorithm. |
| */ |
| protected SecureRandomAdapter(String mdName) |
| { |
| super(); |
| |
| this.mdName = mdName; |
| adaptee.init(Collections.singletonMap(MDGenerator.MD_NAME, mdName)); |
| } |
| |
| public byte[] engineGenerateSeed(int numBytes) |
| { |
| if (numBytes < 1) |
| return new byte[0]; |
| |
| byte[] result = new byte[numBytes]; |
| this.engineNextBytes(result); |
| return result; |
| } |
| |
| public void engineNextBytes(byte[] bytes) |
| { |
| if (! adaptee.isInitialised()) |
| this.engineSetSeed(new byte[0]); |
| try |
| { |
| adaptee.nextBytes(bytes, 0, bytes.length); |
| } |
| catch (LimitReachedException ignored) |
| { |
| } |
| } |
| |
| public void engineSetSeed(byte[] seed) |
| { |
| adaptee.addRandomBytes(seed); |
| } |
| } |