001: /*
002: * $Header: /home/cvs/jakarta-tomcat-4.0/catalina/src/share/org/apache/catalina/util/MD5Encoder.java,v 1.2 2001/07/22 20:25:13 pier Exp $
003: * $Revision: 1.2 $
004: * $Date: 2001/07/22 20:25:13 $
005: *
006: * ====================================================================
007: *
008: * The Apache Software License, Version 1.1
009: *
010: * Copyright (c) 1999 The Apache Software Foundation. All rights
011: * reserved.
012: *
013: * Redistribution and use in source and binary forms, with or without
014: * modification, are permitted provided that the following conditions
015: * are met:
016: *
017: * 1. Redistributions of source code must retain the above copyright
018: * notice, this list of conditions and the following disclaimer.
019: *
020: * 2. Redistributions in binary form must reproduce the above copyright
021: * notice, this list of conditions and the following disclaimer in
022: * the documentation and/or other materials provided with the
023: * distribution.
024: *
025: * 3. The end-user documentation included with the redistribution, if
026: * any, must include the following acknowlegement:
027: * "This product includes software developed by the
028: * Apache Software Foundation (http://www.apache.org/)."
029: * Alternately, this acknowlegement may appear in the software itself,
030: * if and wherever such third-party acknowlegements normally appear.
031: *
032: * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
033: * Foundation" must not be used to endorse or promote products derived
034: * from this software without prior written permission. For written
035: * permission, please contact apache@apache.org.
036: *
037: * 5. Products derived from this software may not be called "Apache"
038: * nor may "Apache" appear in their names without prior written
039: * permission of the Apache Group.
040: *
041: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
042: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
043: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
044: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
045: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
046: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
047: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
048: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
049: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
050: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
051: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
052: * SUCH DAMAGE.
053: * ====================================================================
054: *
055: * This software consists of voluntary contributions made by many
056: * individuals on behalf of the Apache Software Foundation. For more
057: * information on the Apache Software Foundation, please see
058: * <http://www.apache.org/>.
059: *
060: * [Additional notices, if required by prior licensing conditions]
061: *
062: */
063:
064: package org.apache.catalina.util;
065:
066: /**
067: * Encode an MD5 digest into a String.
068: * <p>
069: * The 128 bit MD5 hash is converted into a 32 character long String.
070: * Each character of the String is the hexadecimal representation of 4 bits
071: * of the digest.
072: *
073: * @author Remy Maucherat
074: * @version $Revision: 1.2 $ $Date: 2001/07/22 20:25:13 $
075: */
076:
077: public final class MD5Encoder {
078:
079: // ----------------------------------------------------- Instance Variables
080:
081: private static final char[] hexadecimal = { '0', '1', '2', '3',
082: '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
083:
084: // --------------------------------------------------------- Public Methods
085:
086: /**
087: * Encodes the 128 bit (16 bytes) MD5 into a 32 character String.
088: *
089: * @param binaryData Array containing the digest
090: * @return Encoded MD5, or null if encoding failed
091: */
092: public String encode(byte[] binaryData) {
093:
094: if (binaryData.length != 16)
095: return null;
096:
097: char[] buffer = new char[32];
098:
099: for (int i = 0; i < 16; i++) {
100: int low = (int) (binaryData[i] & 0x0f);
101: int high = (int) ((binaryData[i] & 0xf0) >> 4);
102: buffer[i * 2] = hexadecimal[high];
103: buffer[i * 2 + 1] = hexadecimal[low];
104: }
105:
106: return new String(buffer);
107:
108: }
109:
110: }
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