001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020 package org.apache.directory.server.kerberos.shared.io.decoder; 021 022 023 import java.util.Enumeration; 024 025 import org.apache.directory.server.kerberos.shared.crypto.checksum.ChecksumType; 026 import org.apache.directory.server.kerberos.shared.messages.value.Checksum; 027 import org.apache.directory.shared.asn1.der.DEREncodable; 028 import org.apache.directory.shared.asn1.der.DERInteger; 029 import org.apache.directory.shared.asn1.der.DEROctetString; 030 import org.apache.directory.shared.asn1.der.DERSequence; 031 import org.apache.directory.shared.asn1.der.DERTaggedObject; 032 033 034 /** 035 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 036 * @version $Rev: 588239 $, $Date: 2007-10-25 16:24:28 +0200 (Thu, 25 Oct 2007) $ 037 */ 038 public class ChecksumDecoder 039 { 040 /** 041 * Checksum ::= SEQUENCE { 042 * cksumtype[0] INTEGER, 043 * checksum[1] OCTET STRING 044 * } 045 * @param sequence 046 * @return The {@link Checksum}. 047 */ 048 public static Checksum decode( DERSequence sequence ) 049 { 050 ChecksumType type = ChecksumType.NULL; 051 byte[] data = null; 052 053 for ( Enumeration<DEREncodable> e = sequence.getObjects(); e.hasMoreElements(); ) 054 { 055 DERTaggedObject object = ( DERTaggedObject ) e.nextElement(); 056 int tag = object.getTagNo(); 057 DEREncodable derObject = object.getObject(); 058 059 switch ( tag ) 060 { 061 case 0: 062 DERInteger tag0 = ( DERInteger ) derObject; 063 type = ChecksumType.getTypeByOrdinal( tag0.intValue() ); 064 break; 065 066 case 1: 067 DEROctetString tag1 = ( DEROctetString ) derObject; 068 data = tag1.getOctets(); 069 break; 070 } 071 } 072 073 return new Checksum( type, data ); 074 } 075 }