/*
* Copyright (c) 2001-2007 Sun Microsystems, Inc. All rights reserved.
*
* The Sun Project JXTA(TM) Software License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The end-user documentation included with the redistribution, if any, must
* include the following acknowledgment: "This product includes software
* developed by Sun Microsystems, Inc. for JXTA(TM) technology."
* Alternately, this acknowledgment may appear in the software itself, if
* and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
* not be used to endorse or promote products derived from this software
* without prior written permission. For written permission, please contact
* Project JXTA at http://www.jxta.org.
*
* 5. Products derived from this software may not be called "JXTA", nor may
* "JXTA" appear in their name, without prior written permission of Sun.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SUN
* MICROSYSTEMS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* JXTA is a registered trademark of Sun Microsystems, Inc. in the United
* States and other countries.
*
* Please see the license information page at :
* <http://www.jxta.org/project/www/license.html> for instructions on use of
* the license in source files.
*
* ====================================================================
*
* This software consists of voluntary contributions made by many individuals
* on behalf of Project JXTA. For more information on Project JXTA, please see
* http://www.jxta.org.
*
* This license is based on the BSD license adopted by the Apache Foundation.
*/
package net.jxta.impl.util;
import net.jxta.logging.Logging;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A message digest wrapper to provide hashing using java.security.MesssageDigest
*/
public class JxtaHash {
private final static Logger LOG = Logger.getLogger(JxtaHash.class.getName());
public final static String SHA = "SHA";
public final static String SHA1 = "SHA1";
public final static String MD2 = "MD2";
public final static String MD5 = "MD5";
public final static String DSA = "DSA";
public final static String RSA = "RSA";
public final static String SHA1withDSA = "SHA1WITHDSA";
public final static String DEFAULTECHARSET = "UTF-8";
private MessageDigest dig = null;
/**
* Default JxtaHash constructor, with the default algorithm SHA1
*
*/
public JxtaHash() {
try {
dig = MessageDigest.getInstance(SHA1);
} catch (NoSuchAlgorithmException ex) {
if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
LOG.fine(ex.toString());
}
}
}
/**
* Default JxtaHash constructor, with the default algorithm SHA1
*<p/>This method uses the UFT-8 charset to extract bytes from the expression parameter
*
* @param expression message to hash
* @throws UnsupportedEncodingException If the UFT-8 charset is not supported
*/
public JxtaHash(String expression) throws UnsupportedEncodingException {
this(SHA1, expression);
}
/**
* Constructor for the JxtaHash object
* <p/>This method uses the UFT-8 charset to extract bytes from the expression parameter
*
* @param algorithm algorithm - the name of the algorithm requested
* @param expression expression to digest
* @throws UnsupportedEncodingException If the UFT-8 charset is not supported
*/
public JxtaHash(String algorithm, String expression) throws UnsupportedEncodingException {
this(algorithm, expression.getBytes(DEFAULTECHARSET));
}
/**
* Constructor for the JxtaHash object
*
* @param algorithm algorithm - the name of the algorithm requested
* @param expression expression to digest
*/
public JxtaHash(String algorithm, byte[] expression) {
try {
dig = MessageDigest.getInstance(algorithm);
if (expression != null) {
dig.update(expression);
}
} catch (NoSuchAlgorithmException ex) {
if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
LOG.fine(ex.toString());
}
}
}
/**
* Constructor for the JxtaHash object
*
* @param expression expression to digest
*/
public void update(String expression) {
if (expression != null) {
dig.update(expression.getBytes());
}
}
/**
* Gets the digest as digestInteger
*
* @return The digestInteger value
*/
public BigInteger getDigestInteger() {
return new BigInteger(dig.digest());
}
/**
* Gets the digest as digestInteger
*
* @param expression expression to digest
* @return The digestInteger value
*/
public BigInteger getDigestInteger(byte[] expression) {
dig.reset();
dig.update(expression);
return new BigInteger(dig.digest());
}
/**
* Gets the digest as digestInteger
*
* @param expression expression to digest
* @return The digestInteger value
*/
public BigInteger getDigestInteger(String expression) {
return getDigestInteger(expression.getBytes());
}
/**
* Returns a int whose value is (getDigestInteger mod m).
*
* @param m the modulus.
* @return (getDigestInteger mod m).
*/
public int mod(long m) {
BigInteger bi = getDigestInteger();
BigInteger mod = new BigInteger(longToBytes(m));
BigInteger result = bi.mod(mod);
return result.intValue();
}
/**
* convert a long into the byte array
*
* @param value long value to convert
* @return byte array
*/
private byte[] longToBytes(long value) {
byte[] bytes = new byte[8];
for (int eachByte = 0; eachByte < 8; eachByte++) {
bytes[eachByte] = (byte) (value >> ((7 - eachByte) * 8L));
}
return bytes;
}
}