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 28 29 /** 30 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 31 * @version $Rev$, $Date$ 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 }