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Java > Open Source Codes > com > sun > org > apache > xml > internal > security > keys > keyresolver > implementations > EncryptedKeyResolver


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *
16  */
17 package com.sun.org.apache.xml.internal.security.keys.keyresolver.implementations;
18
19 import java.security.Key JavaDoc;
20 import java.security.PublicKey JavaDoc;
21 import java.security.cert.X509Certificate JavaDoc;
22
23 import javax.crypto.SecretKey;
24
25 import com.sun.org.apache.xml.internal.security.encryption.EncryptedKey;
26 import com.sun.org.apache.xml.internal.security.encryption.XMLCipher;
27 import com.sun.org.apache.xml.internal.security.keys.keyresolver.KeyResolverSpi;
28 import com.sun.org.apache.xml.internal.security.keys.storage.StorageResolver;
29 import com.sun.org.apache.xml.internal.security.utils.EncryptionConstants;
30 import com.sun.org.apache.xml.internal.security.utils.XMLUtils;
31 import org.w3c.dom.Element JavaDoc;
32
33
34 /**
35  * The <code>EncryptedKeyResolver</code> is not a generic resolver. It can
36  * only be for specific instantiations, as the key being unwrapped will
37  * always be of a particular type and will always have been wrapped by
38  * another key which needs to be recursively resolved.
39  *
40  * The <code>EncryptedKeyResolver</code> can therefore only be instantiated
41  * with an algorithm. It can also be instantiated with a key (the KEK) or
42  * will search the static KeyResolvers to find the appropriate key.
43  *
44  * @author Berin Lautenbach
45  */
46
47 public class EncryptedKeyResolver extends KeyResolverSpi {
48
49     /** {@link java.util.logging} logging facility */
50     static java.util.logging.Logger JavaDoc log =
51         java.util.logging.Logger.getLogger(
52                         RSAKeyValueResolver.class.getName());
53
54     
55     Key JavaDoc _key;
56     Key JavaDoc _kek;
57     String JavaDoc _algorithm;
58
59     /**
60      * Constructor for use when a KEK needs to be derived from a KeyInfo
61      * list
62      * @param algorithm
63      */
64     public EncryptedKeyResolver(String JavaDoc algorithm) {
65         _key = null;
66         _kek = null;
67         _algorithm=algorithm;
68     }
69
70     /**
71      * Constructor used for when a KEK has been set
72      * @param algorithm
73      * @param kek
74      */
75
76     public EncryptedKeyResolver(String JavaDoc algorithm, Key JavaDoc kek) {
77         _key = null;
78         _algorithm = algorithm;
79         _kek = kek;
80
81     }
82
83     /**
84      * Method engineCanResolve
85      *
86      * @param element
87      * @param BaseURI
88      * @param storage
89      * @return true if can resolve the key in the element
90      *
91      */
92
93     public boolean engineCanResolve(Element JavaDoc element, String JavaDoc BaseURI,
94                                    StorageResolver storage) {
95       if (true)
96         if (log.isLoggable(java.util.logging.Level.FINE)) log.log(java.util.logging.Level.FINE, "EncryptedKeyResolver - Can I resolve " + element.getTagName());
97
98       if (element == null) {
99          return false;
100       }
101
102       boolean isEncryptedKey = XMLUtils.elementIsInEncryptionSpace(element,
103                               EncryptionConstants._TAG_ENCRYPTEDKEY);
104
105       if (isEncryptedKey) {
106           if (log.isLoggable(java.util.logging.Level.FINE)) log.log(java.util.logging.Level.FINE, "Passed an Encrypted Key");
107           try {
108               XMLCipher cipher = XMLCipher.getInstance();
109               cipher.init(XMLCipher.UNWRAP_MODE, _kek);
110               EncryptedKey ek = cipher.loadEncryptedKey(element);
111               _key = cipher.decryptKey(ek, _algorithm);
112           }
113           catch (Exception JavaDoc e) {}
114       }
115       
116       return (_key != null);
117    }
118
119     /** @inheritDoc */
120    public PublicKey JavaDoc engineResolvePublicKey(
121            Element JavaDoc element, String JavaDoc BaseURI, StorageResolver storage) {
122
123        return null;
124    }
125
126    /** @inheritDoc */
127    public X509Certificate JavaDoc engineResolveX509Certificate(
128            Element JavaDoc element, String JavaDoc BaseURI, StorageResolver storage) {
129       return null;
130    }
131
132    /** @inheritDoc */
133    public javax.crypto.SecretKey engineResolveSecretKey(
134            Element JavaDoc element, String JavaDoc BaseURI, StorageResolver storage) {
135       return (SecretKey) _key;
136    }
137 }
138
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