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Java > Open Source Codes > de > schlichtherle > key > AesKeyProvider


1 /*
2  * Copyright 2006 Schlichtherle IT Services
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 de.schlichtherle.key;
18
19 /**
20  * A {@link KeyProvider} which allows to select the cipher key strength
21  * when creating a new AES encrypted resource or replacing the entire
22  * contents of an already existing AES encrypted resource.
23  * The cipher key strength for the AES encryption may be either 128, 192 or
24  * 256 bits.
25  *
26  * @author Christian Schlichtherle
27  * @version @version@
28  * @since TrueZIP 6.1
29  */
30 public interface AesKeyProvider extends KeyProvider {
31
32     /** Identifier for a 128 bit ciphering key. */
33     int KEY_STRENGTH_128 = 0;
34
35     /** Identifier for a 192 bit ciphering key. */
36     int KEY_STRENGTH_192 = 1;
37
38     /** Identifier for a 256 bit ciphering key. */
39     int KEY_STRENGTH_256 = 2;
40
41     /**
42      * Returns the cipher key strength for the AES encryption.
43      *
44      * @return One of <code>KEY_STRENGTH_128</code>,
45      * <code>KEY_STRENGTH_192</code> or <code>KEY_STRENGTH_256</code>.
46      */
47     int getKeyStrength();
48
49     /**
50      * Sets the cipher key strength for the AES encryption.
51      *
52      * @param keyStrength One of <code>KEY_STRENGTH_128</code>,
53      * <code>KEY_STRENGTH_192</code> or <code>KEY_STRENGTH_256</code>.
54      * @throws IllegalArgumentException If the preconditions for the parameter
55      * do not hold.
56      */
57     void setKeyStrength(int keyStrength);
58 }
59
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