1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20
21 package org.apache.directory.server.kerberos.shared.crypto.checksum;
22
23
24 import java.util.zip.CRC32;
25
26 import org.apache.directory.server.kerberos.shared.crypto.encryption.KeyUsage;
27 import org.apache.directory.shared.kerberos.crypto.checksum.ChecksumType;
28
29
30 /**
31 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
32 */
33 class Crc32Checksum implements ChecksumEngine
34 {
35 public ChecksumType checksumType()
36 {
37 return ChecksumType.CRC32;
38 }
39
40
41 public byte[] calculateChecksum( byte[] data, byte[] key, KeyUsage usage )
42 {
43 CRC32 crc32 = new CRC32();
44 crc32.update( data );
45
46 return int2octet( ( int ) crc32.getValue() );
47 }
48
49
50 private byte[] int2octet( int value )
51 {
52 byte[] bytes = new byte[4];
53 int i, shift;
54
55 for ( i = 0, shift = 24; i < 4; i++, shift -= 8 )
56 {
57 bytes[i] = ( byte ) ( 0xFF & ( value >> shift ) );
58 }
59
60 return bytes;
61 }
62 }