001: /* ====================================================================
002: * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
003: *
004: * Copyright (c) 1995-2002 Jcorporate Ltd. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above copyright
011: * notice, this list of conditions and the following disclaimer.
012: *
013: * 2. Redistributions in binary form must reproduce the above copyright
014: * notice, this list of conditions and the following disclaimer in
015: * the documentation and/or other materials provided with the
016: * distribution.
017: *
018: * 3. The end-user documentation included with the redistribution,
019: * if any, must include the following acknowledgment:
020: * "This product includes software developed by Jcorporate Ltd.
021: * (http://www.jcorporate.com/)."
022: * Alternately, this acknowledgment may appear in the software itself,
023: * if and wherever such third-party acknowledgments normally appear.
024: *
025: * 4. "Jcorporate" and product names such as "Expresso" must
026: * not be used to endorse or promote products derived from this
027: * software without prior written permission. For written permission,
028: * please contact info@jcorporate.com.
029: *
030: * 5. Products derived from this software may not be called "Expresso",
031: * or other Jcorporate product names; nor may "Expresso" or other
032: * Jcorporate product names appear in their name, without prior
033: * written permission of Jcorporate Ltd.
034: *
035: * 6. No product derived from this software may compete in the same
036: * market space, i.e. framework, without prior written permission
037: * of Jcorporate Ltd. For written permission, please contact
038: * partners@jcorporate.com.
039: *
040: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
041: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
042: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
043: * DISCLAIMED. IN NO EVENT SHALL JCORPORATE LTD OR ITS CONTRIBUTORS
044: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
045: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
046: * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
047: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
048: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
049: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
050: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
051: * SUCH DAMAGE.
052: * ====================================================================
053: *
054: * This software consists of voluntary contributions made by many
055: * individuals on behalf of the Jcorporate Ltd. Contributions back
056: * to the project(s) are encouraged when you make modifications.
057: * Please send them to support@jcorporate.com. For more information
058: * on Jcorporate Ltd. and its products, please see
059: * <http://www.jcorporate.com/>.
060: *
061: * Portions of this software are based upon other open source
062: * products and are subject to their respective licenses.
063: */
064:
065: package com.jcorporate.expresso.core.security.strongencryption;
066:
067: import com.jcorporate.expresso.core.security.AbstractRandomNumber;
068: import com.jcorporate.expresso.kernel.exception.ChainedException;
069: import org.apache.log4j.Logger;
070:
071: import java.io.File;
072: import java.io.FileInputStream;
073: import java.io.FileNotFoundException;
074: import java.io.FileOutputStream;
075: import java.io.IOException;
076: import java.io.InputStream;
077: import java.io.OutputStream;
078: import java.security.NoSuchAlgorithmException;
079: import java.security.SecureRandom;
080:
081: /**
082: * Cryptographically Strong Version of the random number generator.
083: * Due to the seeding process, the constructor for this class will
084: * take a significant amount of time to initialize.
085: *
086: * @author Michael Rimov
087: */
088: public final class RandomNumber extends AbstractRandomNumber {
089: private SecureRandom secRand = null;
090: String seedFile = null;
091: int call_count = 0;
092:
093: private static final int SEED_LENGTH = 256;
094:
095: private static final Logger log = Logger
096: .getLogger(RandomNumber.class);
097:
098: /**
099: * Default Constructor
100: *
101: * @throws ChainedException if unable to instantiate the SHA1 Random
102: * number generator
103: */
104: public RandomNumber() throws ChainedException {
105: } /* RandomNumber() */
106:
107: /**
108: * To save some time, we use the last seed generated from a file instead
109: * of loading from scratch
110: *
111: * @throws NoSuchAlgorithmException if we cannot find the SHA1PRNG
112: */
113: public void init() throws ChainedException {
114: try {
115: byte seed[] = null;
116:
117: String configDir = this .getCryptoManager().getRandomSeed();
118: seedFile = configDir + "/random.seed";
119: File f = new File(seedFile);
120: if (f.exists()) {
121: try {
122: InputStream s = new FileInputStream(f);
123: seed = new byte[SEED_LENGTH];
124: int numRead = s.read(seed, 0, SEED_LENGTH);
125: if (numRead < SEED_LENGTH) {
126: seed = null;
127: }
128: } catch (FileNotFoundException ex) {
129: if (log.isDebugEnabled()) {
130: log
131: .debug(
132: "File not found exception loading random seed.",
133: ex);
134: }
135: } catch (java.io.IOException ex) {
136: if (log.isDebugEnabled()) {
137: log.debug("I/O exception loading random seed.",
138: ex);
139: }
140: }
141: }
142:
143: secRand = SecureRandom.getInstance("SHA1PRNG");
144: if (seed != null) {
145: secRand.setSeed(seed);
146: }
147: seed = new byte[SEED_LENGTH];
148: secRand.nextBytes(seed);
149:
150: try {
151: OutputStream os = new FileOutputStream(f);
152: os.write(seed);
153: } catch (IOException ex) {
154: log
155: .warn(
156: "Unable to write random.seed file to config directory",
157: ex);
158: }
159:
160: return;
161: } catch (NoSuchAlgorithmException ex) {
162: throw new ChainedException(
163: "com.javacocporate.common.security.strongencryption.RandomNumber."
164: + "RandomNumber()"
165: + " Unable to load algorithm SHA1PRNG. Your "
166: + "version of the JDK may not support this"
167: + " method.", ex);
168: }
169: }
170:
171: /**
172: * getRandomBytes - Returns a byte array of random bytes. The derived
173: * class determines the actual method used for getting the random data.
174: *
175: * @param numBytes The number of bytes to retrieve
176: * @return An array of random bytes
177: */
178: public byte[] getRandomBytes(int numBytes) {
179: byte[] newBytes = new byte[numBytes];
180: secRand.nextBytes(newBytes);
181:
182: //
183: //Write a new seed file every ten calls to getRandomBytes
184: //
185: call_count = (call_count++) % 10;
186:
187: if (call_count == 0) {
188: byte seed[] = new byte[SEED_LENGTH];
189: secRand.nextBytes(seed);
190:
191: try {
192: OutputStream os = new FileOutputStream(new File(
193: seedFile));
194: os.write(seed);
195: } catch (IOException ex) {
196: System.err
197: .println("Unable to write random.seed file to config directory");
198: }
199: }
200:
201: return newBytes;
202: } /* getRandomBytes(int) */
203:
204: } /* RandomNumber */
205:
206: /* RandomNumber */
|