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1   /**
2    *
3    * Copyright 2005 The Apache Software Foundation
4    *
5    *  Licensed under the Apache License, Version 2.0 (the "License");
6    *  you may not use this file except in compliance with the License.
7    *  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  package org.apache.geronimo.util;
18  
19  import org.apache.geronimo.util.encoders.HexEncoder;
20  
21  import java.security.cert.Certificate;
22  import java.security.cert.CertificateEncodingException;
23  import java.security.NoSuchAlgorithmException;
24  import java.security.MessageDigest;
25  import java.io.IOException;
26  import java.io.ByteArrayOutputStream;
27  import java.util.regex.Matcher;
28  import java.util.regex.Pattern;
29  
30  /**
31   * Various utility functions for dealing with X.509 certificates
32   *
33   * @version $Rev: 410741 $ $Date: 2006-05-31 21:35:48 -0700 (Wed, 31 May 2006) $
34   */
35  public class CertificateUtil {
36      public static String generateFingerprint(Certificate cert, String digestAlgorithm) throws NoSuchAlgorithmException, CertificateEncodingException, IOException {
37          MessageDigest md = MessageDigest.getInstance(digestAlgorithm);
38          byte[] digest = md.digest(cert.getEncoded());
39          ByteArrayOutputStream out = new ByteArrayOutputStream(digest.length*2);
40          new HexEncoder().encode(digest, 0, digest.length, out);
41          String all = new String(out.toByteArray(), "US-ASCII").toUpperCase();
42          Matcher matcher = Pattern.compile("..").matcher(all);
43          StringBuffer buf = new StringBuffer();
44          while(matcher.find()) {
45              if(buf.length() > 0) {
46                  buf.append(":");
47              }
48              buf.append(matcher.group());
49          }
50          return buf.toString();
51      }
52  }