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 package org.apache.directory.server.kerberos.shared.io.decoder;
21
22
23 import java.io.IOException;
24 import java.util.Enumeration;
25
26 import org.apache.directory.server.kerberos.shared.crypto.encryption.EncryptionType;
27 import org.apache.directory.server.kerberos.shared.messages.value.EncryptedData;
28 import org.apache.directory.shared.asn1.der.ASN1InputStream;
29 import org.apache.directory.shared.asn1.der.DEREncodable;
30 import org.apache.directory.shared.asn1.der.DERInteger;
31 import org.apache.directory.shared.asn1.der.DEROctetString;
32 import org.apache.directory.shared.asn1.der.DERSequence;
33 import org.apache.directory.shared.asn1.der.DERTaggedObject;
34
35
36 /**
37 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
38 * @version $Rev: 587682 $, $Date: 2007-10-24 00:47:43 +0200 (Mi, 24 Okt 2007) $
39 */
40 public class EncryptedDataDecoder
41 {
42 /**
43 * Decodes a byte array into an {@link EncryptedData}.
44 *
45 * @param encodedEncryptedData
46 * @return The {@link EncryptedData}.
47 * @throws IOException
48 */
49 public static EncryptedData decode( byte[] encodedEncryptedData ) throws IOException
50 {
51 ASN1InputStream ais = new ASN1InputStream( encodedEncryptedData );
52
53 DERSequence sequence = ( DERSequence ) ais.readObject();
54
55 return decode( sequence );
56 }
57
58
59 /**
60 * Decodes a {@link DERSequence} into an {@link EncryptedData}.
61 *
62 * EncryptedData ::= SEQUENCE {
63 * etype[0] INTEGER, -- EncryptionEngine
64 * kvno[1] INTEGER OPTIONAL,
65 * cipher[2] OCTET STRING -- ciphertext
66 * }
67 *
68 * @param sequence
69 * @return The {@link EncryptedData}.
70 */
71 public static EncryptedData decode( DERSequence sequence )
72 {
73 EncryptedData encryptedData = new EncryptedData();
74
75 for ( Enumeration<DEREncodable> e = sequence.getObjects(); e.hasMoreElements(); )
76 {
77 DERTaggedObject object = ( DERTaggedObject ) e.nextElement();
78 int tag = object.getTagNo();
79 DEREncodable derObject = object.getObject();
80
81 switch ( tag )
82 {
83 case 0:
84 DERInteger etype = ( DERInteger ) derObject;
85 encryptedData.setEType( EncryptionType.getTypeByOrdinal( etype.intValue() ) );
86 break;
87
88 case 1:
89 DERInteger kvno = ( DERInteger ) derObject;
90 encryptedData.setKvno( kvno.intValue() );
91 break;
92
93 case 2:
94 DEROctetString cipher = ( DEROctetString ) derObject;
95 encryptedData.setCipher( cipher.getOctets() );
96 break;
97 }
98 }
99
100 return encryptedData;
101 }
102 }