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.EncryptionTypeInfo2Entry;
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.DERGeneralString;
031    import org.apache.directory.shared.asn1.der.DERInteger;
032    import org.apache.directory.shared.asn1.der.DEROctetString;
033    import org.apache.directory.shared.asn1.der.DERSequence;
034    import org.apache.directory.shared.asn1.der.DERTaggedObject;
035    
036    
037    /**
038     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
039     * @version $Rev: 540371 $, $Date: 2007-05-21 17:00:43 -0700 (Mon, 21 May 2007) $
040     */
041    public class EncryptionTypeInfo2Decoder
042    {
043        /**
044         * Decodes a byte array into an array of {@link EncryptionTypeInfo2Entry}.
045         *
046         * @param encodedEntries
047         * @return The array of {@link EncryptionTypeInfo2Entry}.
048         * @throws IOException
049         */
050        public EncryptionTypeInfo2Entry[] decode( byte[] encodedEntries ) throws IOException
051        {
052            ASN1InputStream ais = new ASN1InputStream( encodedEntries );
053    
054            DERSequence sequence = ( DERSequence ) ais.readObject();
055    
056            return decodeSequence( sequence );
057        }
058    
059    
060        /**
061         * ETYPE-INFO2             ::= SEQUENCE SIZE (1..MAX) OF ETYPE-INFO2-ENTRY
062         */
063        protected static EncryptionTypeInfo2Entry[] decodeSequence( DERSequence sequence )
064        {
065            EncryptionTypeInfo2Entry[] entrySequence = new EncryptionTypeInfo2Entry[sequence.size()];
066    
067            int ii = 0;
068            for ( Enumeration<DEREncodable> e = sequence.getObjects(); e.hasMoreElements(); )
069            {
070                DERSequence object = (DERSequence)e.nextElement();
071                entrySequence[ii] = decode( object );
072                ii++;
073            }
074    
075            return entrySequence;
076        }
077    
078    
079        /**
080         * ETYPE-INFO2-ENTRY       ::= SEQUENCE {
081         *         etype           [0] Int32,
082         *         salt            [1] KerberosString OPTIONAL,
083         *         s2kparams       [2] OCTET STRING OPTIONAL
084         * }
085         */
086        protected static EncryptionTypeInfo2Entry decode( DERSequence sequence )
087        {
088            EncryptionType encryptionType = EncryptionType.NULL;
089            String salt = new String();
090            byte[] s2kparams = new byte[0];
091    
092            for ( Enumeration<DEREncodable> e = sequence.getObjects(); e.hasMoreElements(); )
093            {
094                DERTaggedObject object = (DERTaggedObject)e.nextElement();
095                int tag = object.getTagNo();
096                DEREncodable derObject = object.getObject();
097    
098                switch ( tag )
099                {
100                    case 0:
101                        DERInteger tag0 = ( DERInteger ) derObject;
102                        encryptionType = EncryptionType.getTypeByOrdinal( tag0.intValue() );
103                        break;
104                    case 1:
105                        DERGeneralString tag1 = ( DERGeneralString ) derObject;
106                        salt = tag1.getString();
107                        break;
108                    case 2:
109                        DEROctetString tag2 = ( DEROctetString ) derObject;
110                        s2kparams = tag2.getOctets();
111                        break;
112                }
113            }
114    
115            return new EncryptionTypeInfo2Entry( encryptionType, salt, s2kparams );
116        }
117    }