001    /**
002     *
003     * Copyright 2005 The Apache Software Foundation
004     *
005     *  Licensed under the Apache License, Version 2.0 (the "License");
006     *  you may not use this file except in compliance with the License.
007     *  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     *  Unless required by applicable law or agreed to in writing, software
012     *  distributed under the License is distributed on an "AS IS" BASIS,
013     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     *  See the License for the specific language governing permissions and
015     *  limitations under the License.
016     */
017    package org.apache.geronimo.util;
018    
019    import org.apache.geronimo.util.encoders.HexEncoder;
020    
021    import java.security.cert.Certificate;
022    import java.security.cert.CertificateEncodingException;
023    import java.security.NoSuchAlgorithmException;
024    import java.security.MessageDigest;
025    import java.io.IOException;
026    import java.io.ByteArrayOutputStream;
027    import java.util.regex.Matcher;
028    import java.util.regex.Pattern;
029    
030    /**
031     * Various utility functions for dealing with X.509 certificates
032     *
033     * @version $Rev: 410741 $ $Date: 2006-05-31 21:35:48 -0700 (Wed, 31 May 2006) $
034     */
035    public class CertificateUtil {
036        public static String generateFingerprint(Certificate cert, String digestAlgorithm) throws NoSuchAlgorithmException, CertificateEncodingException, IOException {
037            MessageDigest md = MessageDigest.getInstance(digestAlgorithm);
038            byte[] digest = md.digest(cert.getEncoded());
039            ByteArrayOutputStream out = new ByteArrayOutputStream(digest.length*2);
040            new HexEncoder().encode(digest, 0, digest.length, out);
041            String all = new String(out.toByteArray(), "US-ASCII").toUpperCase();
042            Matcher matcher = Pattern.compile("..").matcher(all);
043            StringBuffer buf = new StringBuffer();
044            while(matcher.find()) {
045                if(buf.length() > 0) {
046                    buf.append(":");
047                }
048                buf.append(matcher.group());
049            }
050            return buf.toString();
051        }
052    }