1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.crypto.provider;
27
28 import java.security.InvalidKeyException;
29 import java.security.ProviderException;
30
31 /**
32 * This class represents ciphers in electronic codebook (ECB) mode.
33 *
34 * <p>This mode is implemented independently of a particular cipher.
35 * Ciphers to which this mode should apply (e.g., DES) must be
36 * <i>plugged-in</i> using the constructor.
37 *
38 * <p>NOTE: This class does not deal with buffering or padding.
39 *
40 * @author Gigi Ankeny
41 */
42
43 final class ElectronicCodeBook extends FeedbackCipher {
44
45 ElectronicCodeBook(SymmetricCipher embeddedCipher) {
46 super(embeddedCipher);
47 }
48
49 /**
50 * Gets the name of the feedback mechanism
51 *
52 * @return the name of the feedback mechanism
53 */
54 String getFeedback() {
55 return "ECB";
56 }
57
58 /**
59 * Resets the iv to its original value.
60 * This is used when doFinal is called in the Cipher class, so that the
61 * cipher can be reused (with its original iv).
62 */
63 void reset() {
64 // empty
65 }
66
67 /**
68 * Save the current content of this cipher.
69 */
70 void save() {}
71
72 /**
73 * Restores the content of this cipher to the previous saved one.
74 */
75 void restore() {}
76
77 /**
78 * Initializes the cipher in the specified mode with the given key
79 * and iv.
80 *
81 * @param decrypting flag indicating encryption or decryption
82 * @param algorithm the algorithm name
83 * @param key the key
84 * @param iv the iv
85 *
86 * @exception InvalidKeyException if the given key is inappropriate for
87 * initializing this cipher
88 */
89 void init(boolean decrypting, String algorithm, byte[] key, byte[] iv)
90 throws InvalidKeyException {
91 if ((key == null) || (iv != null)) {
92 throw new InvalidKeyException("Internal error");
93 }
94 embeddedCipher.init(decrypting, algorithm, key);
95 }
96
97 /**
98 * Performs encryption operation.
99 *
100 * <p>The input plain text <code>in</code>, starting at
101 * <code>inOff</code> and ending at * <code>(inOff + len - 1)</code>,
102 * is encrypted. The result is stored in <code>out</code>, starting at
103 * <code>outOff</code>.
104 *
105 * @param in the buffer with the input data to be encrypted
106 * @param inOff the offset in <code>plain</code>
107 * @param len the length of the input data
108 * @param out the buffer for the result
109 * @param outOff the offset in <code>cipher</code>
110 * @exception ProviderException if <code>len</code> is not
111 * a multiple of the block size
112 * @return the length of the encrypted data
113 */
114 int encrypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
115 embeddedCipher.encryptBlocks(in, inOff, out, outOff, len);
116 return len;
117 }
118
119 /**
120 * Performs decryption operation.
121 *
122 * <p>The input cipher text <code>in</code>, starting at
123 * <code>inOff</code> and ending at * <code>(inOff + len - 1)</code>,
124 * is decrypted.The result is stored in <code>out</code>, starting at
125 * <code>outOff</code>.
126 *
127 * @param in the buffer with the input data to be decrypted
128 * @param inOff the offset in <code>cipherOffset</code>
129 * @param len the length of the input data
130 * @param out the buffer for the result
131 * @param outOff the offset in <code>plain</code>
132 * @exception ProviderException if <code>len</code> is not
133 * a multiple of the block size
134 * @return the length of the decrypted data
135 */
136 int decrypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
137 embeddedCipher.decryptBlocks(in, inOff, out, outOff, len);
138 return len;
139 }
140 }