| /* UMacRandomSpi.java -- |
| Copyright (C) 2001, 2002, 2006, 2010 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.javax.crypto.jce.prng; |
| |
| import gnu.java.security.Configuration; |
| import gnu.java.security.Registry; |
| import gnu.java.security.prng.LimitReachedException; |
| import gnu.java.security.jce.prng.SecureRandomAdapter; |
| import gnu.javax.crypto.cipher.IBlockCipher; |
| import gnu.javax.crypto.prng.UMacGenerator; |
| |
| import java.security.SecureRandomSpi; |
| import java.util.HashMap; |
| import java.util.Random; |
| import java.util.logging.Logger; |
| |
| /** |
| * An <em>Adapter</em> class around {@link UMacGenerator} to allow using this |
| * algorithm as a JCE {@link java.security.SecureRandom}. |
| */ |
| public class UMacRandomSpi |
| extends SecureRandomSpi |
| { |
| private static final Logger log = Configuration.DEBUG ? |
| Logger.getLogger(UMacRandomSpi.class.getName()) : null; |
| |
| /** Class-wide prng to generate random material for the underlying prng. */ |
| private static final UMacGenerator prng; // blank final |
| static |
| { |
| prng = new UMacGenerator(); |
| resetLocalPRNG(); |
| } |
| // error messages |
| private static final String MSG = "Exception while setting up a " |
| + Registry.UMAC_PRNG + " SPI: "; |
| private static final String RETRY = "Retry..."; |
| /** Our underlying prng instance. */ |
| private UMacGenerator adaptee = new UMacGenerator(); |
| |
| // default 0-arguments constructor |
| |
| private static void resetLocalPRNG() |
| { |
| HashMap attributes = new HashMap(); |
| attributes.put(UMacGenerator.CIPHER, Registry.AES_CIPHER); |
| byte[] key = new byte[128 / 8]; // AES default key size |
| Random rand = new Random(System.currentTimeMillis()); |
| rand.nextBytes(key); |
| attributes.put(IBlockCipher.KEY_MATERIAL, key); |
| int index = rand.nextInt() & 0xFF; |
| attributes.put(UMacGenerator.INDEX, Integer.valueOf(index)); |
| prng.setup(attributes); |
| } |
| |
| public byte[] engineGenerateSeed(int numBytes) |
| { |
| return SecureRandomAdapter.getSeed(numBytes); |
| } |
| |
| public void engineNextBytes(byte[] bytes) |
| { |
| if (! adaptee.isInitialised()) |
| engineSetSeed(engineGenerateSeed(32)); |
| while (true) |
| { |
| try |
| { |
| adaptee.nextBytes(bytes, 0, bytes.length); |
| break; |
| } |
| catch (LimitReachedException x) |
| { // reseed the generator |
| resetLocalPRNG(); |
| } |
| } |
| } |
| |
| public void engineSetSeed(byte[] seed) |
| { |
| // compute the total number of random bytes required to setup adaptee |
| int materialLength = 0; |
| materialLength += 16; // key material size |
| materialLength++; // index size |
| byte[] material = new byte[materialLength]; |
| // use as much as possible bytes from the seed |
| int materialOffset = 0; |
| int materialLeft = material.length; |
| if (seed.length > 0) |
| { // copy some bytes into key and update indices |
| int lenToCopy = Math.min(materialLength, seed.length); |
| System.arraycopy(seed, 0, material, 0, lenToCopy); |
| materialOffset += lenToCopy; |
| materialLeft -= lenToCopy; |
| } |
| if (materialOffset > 0) // generate the rest |
| { |
| while (true) |
| { |
| try |
| { |
| prng.nextBytes(material, materialOffset, materialLeft); |
| break; |
| } |
| catch (IllegalStateException x) // should not happen |
| { |
| throw new InternalError(MSG + String.valueOf(x)); |
| } |
| catch (LimitReachedException x) |
| { |
| if (Configuration.DEBUG) |
| { |
| log.fine(MSG + String.valueOf(x)); |
| log.fine(RETRY); |
| } |
| } |
| } |
| } |
| // setup the underlying adaptee instance |
| HashMap attributes = new HashMap(); |
| // use AES cipher with 128-bit block size |
| attributes.put(UMacGenerator.CIPHER, Registry.AES_CIPHER); |
| // specify the key |
| byte[] key = new byte[16]; |
| System.arraycopy(material, 0, key, 0, 16); |
| attributes.put(IBlockCipher.KEY_MATERIAL, key); |
| // use a 1-byte index |
| attributes.put(UMacGenerator.INDEX, Integer.valueOf(material[16] & 0xFF)); |
| adaptee.init(attributes); |
| } |
| } |