/* 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:</b> <p> * * 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);        }    }}