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Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/jce/prng/ICMRandomSpi.java')
| -rw-r--r-- | libjava/classpath/gnu/javax/crypto/jce/prng/ICMRandomSpi.java | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/jce/prng/ICMRandomSpi.java b/libjava/classpath/gnu/javax/crypto/jce/prng/ICMRandomSpi.java new file mode 100644 index 00000000000..d04b782f9f5 --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/jce/prng/ICMRandomSpi.java @@ -0,0 +1,260 @@ +/* ICMRandomSpi.java -- + Copyright (C) 2001, 2002, 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.javax.crypto.jce.prng; + +import gnu.java.security.Registry; +import gnu.javax.crypto.cipher.IBlockCipher; +import gnu.javax.crypto.prng.ICMGenerator; +import gnu.java.security.prng.LimitReachedException; + +import java.io.PrintWriter; +import java.math.BigInteger; +import java.security.SecureRandomSpi; +import java.util.HashMap; +import java.util.Random; + +/** + * <p>An <em>Adapter</em> class around {@link ICMGenerator} to allow using this + * algorithm as a JCE {@link java.security.SecureRandom}.</p> + */ +public class ICMRandomSpi extends SecureRandomSpi +{ + + // Debugging methods and variables + // ------------------------------------------------------------------------- + + private static final String NAME = "ICMRandomSpi"; + + private static final boolean DEBUG = false; + + private static final int debuglevel = 0; + + private static final PrintWriter err = new PrintWriter(System.out, true); + + private static void debug(String s) + { + err.println(">>> " + NAME + ": " + s); + } + + // Constants and variables + // ------------------------------------------------------------------------- + + /** Class-wide prng to generate random material for the underlying prng.*/ + private static final ICMGenerator prng; // blank final + static + { + prng = new ICMGenerator(); + resetLocalPRNG(); + } + + // error messages + private static final String MSG = "Exception while setting up an " + + Registry.ICM_PRNG + " SPI: "; + + private static final String RETRY = "Retry..."; + + private static final String LIMIT_REACHED_MSG = "Limit reached: "; + + private static final String RESEED = "Re-seed..."; + + /** Our underlying prng instance. */ + private ICMGenerator adaptee = new ICMGenerator(); + + // Constructor(s) + // ------------------------------------------------------------------------- + + // default 0-arguments constructor + + // Class methods + // ------------------------------------------------------------------------- + + private static void resetLocalPRNG() + { + if (DEBUG && debuglevel > 8) + debug(">>> resetLocalPRNG()"); + HashMap attributes = new HashMap(); + attributes.put(ICMGenerator.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 aesBlockSize = 128 / 8; // AES block size in bytes + byte[] offset = new byte[aesBlockSize]; + rand.nextBytes(offset); + attributes.put(ICMGenerator.OFFSET, offset); + int ndxLen = 0; // the segment length + // choose a random value between 1 and aesBlockSize / 2 + int limit = aesBlockSize / 2; + while (ndxLen < 1 || ndxLen > limit) + { + ndxLen = rand.nextInt(limit + 1); + } + attributes.put(ICMGenerator.SEGMENT_INDEX_LENGTH, new Integer(ndxLen)); + byte[] index = new byte[ndxLen]; + rand.nextBytes(index); + attributes.put(ICMGenerator.SEGMENT_INDEX, new BigInteger(1, index)); + + prng.setup(attributes); + if (DEBUG && debuglevel > 8) + debug("<<< resetLocalPRNG()"); + } + + // Instance methods + // ------------------------------------------------------------------------- + + // java.security.SecureRandomSpi interface implementation ------------------ + + public byte[] engineGenerateSeed(int numBytes) + { + if (DEBUG && debuglevel > 8) + debug(">>> engineGenerateSeed()"); + if (numBytes < 1) + { + if (DEBUG && debuglevel > 8) + debug("<<< engineGenerateSeed()"); + return new byte[0]; + } + byte[] result = new byte[numBytes]; + this.engineNextBytes(result); + if (DEBUG && debuglevel > 8) + debug("<<< engineGenerateSeed()"); + return result; + } + + public void engineNextBytes(byte[] bytes) + { + if (DEBUG && debuglevel > 8) + debug(">>> engineNextBytes()"); + if (!adaptee.isInitialised()) + { + this.engineSetSeed(new byte[0]); + } + + while (true) + { + try + { + adaptee.nextBytes(bytes, 0, bytes.length); + break; + } + catch (LimitReachedException x) + { // reseed the generator + if (DEBUG) + { + debug(LIMIT_REACHED_MSG + String.valueOf(x)); + x.printStackTrace(err); + debug(RESEED); + } + resetLocalPRNG(); + } + } + if (DEBUG && debuglevel > 8) + debug("<<< engineNextBytes()"); + } + + public void engineSetSeed(byte[] seed) + { + if (DEBUG && debuglevel > 8) + debug(">>> engineSetSeed()"); + // compute the total number of random bytes required to setup adaptee + int materialLength = 0; + materialLength += 16; // key material size + materialLength += 16; // offset size + materialLength += 8; // index size == half of an AES block + 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 (DEBUG) + { + debug(MSG + String.valueOf(x)); + debug(RETRY); + } + } + } + } + + // setup the underlying adaptee instance + HashMap attributes = new HashMap(); + + // use AES cipher with 128-bit block size + attributes.put(ICMGenerator.CIPHER, Registry.AES_CIPHER); + // use an index the size of quarter of an AES block + attributes.put(ICMGenerator.SEGMENT_INDEX_LENGTH, new Integer(4)); + // specify the key + byte[] key = new byte[16]; + System.arraycopy(material, 0, key, 0, 16); + attributes.put(IBlockCipher.KEY_MATERIAL, key); + // specify the offset + byte[] offset = new byte[16]; + System.arraycopy(material, 16, offset, 0, 16); + attributes.put(ICMGenerator.OFFSET, offset); + // specify the index + byte[] index = new byte[8]; + System.arraycopy(material, 32, index, 0, 8); + attributes.put(ICMGenerator.SEGMENT_INDEX, new BigInteger(1, index)); + + adaptee.init(attributes); + if (DEBUG && debuglevel > 8) + debug("<<< engineSetSeed()"); + } +}
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