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.io.IOException; 024 import java.util.Enumeration; 025 026 import org.apache.directory.server.kerberos.shared.crypto.encryption.EncryptionType; 027 import org.apache.directory.server.kerberos.shared.messages.value.EncryptionKey; 028 import org.apache.directory.shared.asn1.der.ASN1InputStream; 029 import org.apache.directory.shared.asn1.der.DEREncodable; 030 import org.apache.directory.shared.asn1.der.DERInteger; 031 import org.apache.directory.shared.asn1.der.DEROctetString; 032 import org.apache.directory.shared.asn1.der.DERSequence; 033 import org.apache.directory.shared.asn1.der.DERTaggedObject; 034 035 036 /** 037 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 038 * @version $Rev: 540371 $, $Date: 2007-05-22 02:00:43 +0200 (Tue, 22 May 2007) $ 039 */ 040 public class EncryptionKeyDecoder 041 { 042 /** 043 * Decodes a byte array into an {@link EncryptionKey}. 044 * 045 * @param encodedEncryptionKey 046 * @return The {@link EncryptionKey}. 047 * @throws IOException 048 */ 049 public static EncryptionKey decode( byte[] encodedEncryptionKey ) throws IOException 050 { 051 ASN1InputStream ais = new ASN1InputStream( encodedEncryptionKey ); 052 053 DERSequence sequence = ( DERSequence ) ais.readObject(); 054 055 return decode( sequence ); 056 } 057 058 059 /** 060 * EncryptionKey ::= SEQUENCE { 061 * keytype[0] INTEGER, 062 * keyvalue[1] OCTET STRING 063 * } 064 */ 065 protected static EncryptionKey decode( DERSequence sequence ) 066 { 067 EncryptionType type = EncryptionType.NULL; 068 byte[] data = null; 069 070 for ( Enumeration e = sequence.getObjects(); e.hasMoreElements(); ) 071 { 072 DERTaggedObject object = ( DERTaggedObject ) e.nextElement(); 073 int tag = object.getTagNo(); 074 DEREncodable derObject = object.getObject(); 075 076 switch ( tag ) 077 { 078 case 0: 079 DERInteger tag0 = ( DERInteger ) derObject; 080 type = EncryptionType.getTypeByOrdinal( tag0.intValue() ); 081 break; 082 case 1: 083 DEROctetString tag1 = ( DEROctetString ) derObject; 084 data = tag1.getOctets(); 085 break; 086 } 087 } 088 089 return new EncryptionKey( type, data ); 090 } 091 }