HSQLDB example source code file (MD5.java)

This example HSQLDB source code file (MD5.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

io, iso-8859-1, md5, md5, messagedigest, nosuchalgorithmexception, runtimeexception, runtimeexception, security, string, string, unsupportedencodingexception, unsupportedencodingexception

The HSQLDB MD5.java source code

/* Copyright (c) 2001-2004, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 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.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS 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 HSQL DEVELOPMENT GROUP, HSQLDB.ORG, 
 * OR 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.
 */


package org.hsqldb.lib;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

// boucherb@users 20030705 - patch 1.7.2 - renamed methods to allow sp/sf calls
// under HSQLDB's current inability to resolve method name overloads.

/**
 * Provides a static utility interface to an MD5 digest algorithm
 * obtained through the java.security.MessageDigest spi. <p>
 *
 * Database end-users may wish to access the services of this class
 * to provide, for instance, application user lookup tables with
 * one-way password encryption.  For example: <p>
 *
 * <pre>
 * -- DDL
 * CREATE TABLE USERS(UID INTEGER IDENTITY, UNAME VARCHAR, UPASS VARCHAR, UNIQUE(UNAME))
 * CREATE ALIAS MD5 FOR "org.hsqldb.lib.MD5.encodeString"
 *
 * -- DML & DQL
 * INSERT INTO USERS(UNAME, UPASS) VALUES('joe', MD5('passwd'))
 * UPDATE USERS SET UPASS = MD5('newpasswd') WHERE UNAME = 'joe' AND UPASS = MD5('oldpasswd')
 * SELECT UID FROM USERS WHERE UNAME = 'joe' AND UPASS = MD5('logonpasswd')
 * </pre>
 *
 * <b>NOTE: 

 *
 * Although it is possible that a particular JVM / application installation may
 * encounter NoSuchAlgorithmException when attempting to get a jce MD5 message
 * digest generator, the likelyhood is very small for almost all JDK/JRE 1.1
 * and later  JVM implementations, as the Sun java.security package has come,
 * by default, with a jce MD5 message digest generator since JDK 1.1 was
 * released.  The HSLQLDB project could have provided an MD5 implementation to
 * guarantee presence, but this class is much more lightweight and still allows
 * clients to install / use  custom implementations through the
 * java.security.MessageDigest spi, for instance if there is no service
 * provided by default under the target JVM of choice or if a client has
 * developed / provides, say, a faster MD5 message digest implementation.
 * In short, this class is a convenience that allows HSQLDB SQL Function and
 * Stored Procedure style access to any underlying MD5 message digest algorithm
 * obtained via the java.security.MessageDigest spi
 *
 * @author boucherb@users.sourceforge.net
 * @version 1.7.2
 * @since 1.7.2
 */
public final class MD5 {

    /**
     * The jce MD5 message digest generator.
     */
    private static MessageDigest md5;

    /**
     * Retrieves a hexidecimal character sequence representing the MD5
     * digest of the specified character sequence, using the specified
     * encoding to first convert the character sequence into a byte sequence.
     * If the specified encoding is null, then ISO-8859-1 is assumed
     *
     * @param string the string to encode.
     * @param encoding the encoding used to convert the string into the
     *      byte sequence to submit for MD5 digest
     * @return a hexidecimal character sequence representing the MD5
     *      digest of the specified string
     * @throws HsqlUnsupportedOperationException if an MD5 digest
     *      algorithm is not available through the
     *      java.security.MessageDigest spi or the requested
     *      encoding is not available
     */
    public static final String encodeString(String string,
            String encoding) throws RuntimeException {
        return StringConverter.byteToHex(digestString(string, encoding));
    }

    /**
     * Retrieves a byte sequence representing the MD5 digest of the
     * specified character sequence, using the specified encoding to
     * first convert the character sequence into a byte sequence.
     * If the specified encoding is null, then ISO-8859-1 is
     * assumed.
     *
     * @param string the string to digest.
     * @param encoding the character encoding.
     * @return the digest as an array of 16 bytes.
     * @throws HsqlUnsupportedOperationException if an MD5 digest
     *      algorithm is not available through the
     *      java.security.MessageDigest spi or the requested
     *      encoding is not available
     */
    public static byte[] digestString(String string,
                                      String encoding)
                                      throws RuntimeException {

        byte[] data;

        if (encoding == null) {
            encoding = "ISO-8859-1";
        }

        try {
            data = string.getBytes(encoding);
        } catch (UnsupportedEncodingException x) {
            throw new RuntimeException(x.toString());
        }

        return digestBytes(data);
    }

    /**
     * Retrieves a byte sequence representing the MD5 digest of the
     * specified byte sequence.
     *
     * @param data the data to digest.
     * @return the MD5 digest as an array of 16 bytes.
     * @throws HsqlUnsupportedOperationException if an MD5 digest
     *       algorithm is not available through the
     *       java.security.MessageDigest spi
     */
    public static final byte[] digestBytes(byte[] data)
    throws RuntimeException {

        synchronized (MD5.class) {
            if (md5 == null) {
                try {
                    md5 = MessageDigest.getInstance("MD5");
                } catch (NoSuchAlgorithmException e) {
                    throw new RuntimeException(e.toString());
                }
            }

            return md5.digest(data);
        }
    }
}