2
|
1 |
/*
|
7043
|
2 |
* Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
|
2
|
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
|
5506
|
7 |
* published by the Free Software Foundation. Oracle designates this
|
2
|
8 |
* particular file as subject to the "Classpath" exception as provided
|
5506
|
9 |
* by Oracle in the LICENSE file that accompanied this code.
|
2
|
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 |
*
|
5506
|
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.
|
2
|
24 |
*/
|
|
25 |
|
|
26 |
package com.sun.crypto.provider;
|
|
27 |
|
|
28 |
import java.security.*;
|
|
29 |
import java.security.spec.AlgorithmParameterSpec;
|
|
30 |
|
|
31 |
import javax.crypto.*;
|
|
32 |
|
|
33 |
/**
|
|
34 |
* Implementation of the ARCFOUR cipher, an algorithm apparently compatible
|
|
35 |
* with RSA Security's RC4(tm) cipher. The description of this algorithm was
|
|
36 |
* taken from Bruce Schneier's book Applied Cryptography, 2nd ed.,
|
|
37 |
* section 17.1.
|
|
38 |
*
|
|
39 |
* We support keys from 40 to 1024 bits. ARCFOUR would allow for keys shorter
|
|
40 |
* than 40 bits, but that is too insecure for us to permit.
|
|
41 |
*
|
|
42 |
* Note that we subclass CipherSpi directly and do not use the CipherCore
|
|
43 |
* framework. That was designed to simplify implementation of block ciphers
|
|
44 |
* and does not offer any advantages for stream ciphers such as ARCFOUR.
|
|
45 |
*
|
|
46 |
* @since 1.5
|
|
47 |
* @author Andreas Sterbenz
|
|
48 |
*/
|
|
49 |
public final class ARCFOURCipher extends CipherSpi {
|
|
50 |
|
|
51 |
// state array S, 256 entries. The entries are 8-bit, but we use an int[]
|
|
52 |
// because int arithmetic is much faster than in Java than bytes.
|
|
53 |
private final int[] S;
|
|
54 |
|
|
55 |
// state indices i and j. Called is and js to avoid collision with
|
|
56 |
// local variables. 'is' is set to -1 after a call to doFinal()
|
|
57 |
private int is, js;
|
|
58 |
|
|
59 |
// the bytes of the last key used (if any)
|
|
60 |
// we need this to re-initialize after a call to doFinal()
|
|
61 |
private byte[] lastKey;
|
|
62 |
|
|
63 |
// called by the JCE framework
|
|
64 |
public ARCFOURCipher() {
|
|
65 |
S = new int[256];
|
|
66 |
}
|
|
67 |
|
|
68 |
// core key setup code. initializes S, is, and js
|
|
69 |
// assumes key is non-null and between 40 and 1024 bit
|
|
70 |
private void init(byte[] key) {
|
|
71 |
// initialize S[i] to i
|
|
72 |
for (int i = 0; i < 256; i++) {
|
|
73 |
S[i] = i;
|
|
74 |
}
|
|
75 |
|
|
76 |
// we avoid expanding key to 256 bytes and instead keep a separate
|
|
77 |
// counter ki = i mod key.length.
|
|
78 |
for (int i = 0, j = 0, ki = 0; i < 256; i++) {
|
|
79 |
int Si = S[i];
|
|
80 |
j = (j + Si + key[ki]) & 0xff;
|
|
81 |
S[i] = S[j];
|
|
82 |
S[j] = Si;
|
|
83 |
ki++;
|
|
84 |
if (ki == key.length) {
|
|
85 |
ki = 0;
|
|
86 |
}
|
|
87 |
}
|
|
88 |
|
|
89 |
// set indices to 0
|
|
90 |
is = 0;
|
|
91 |
js = 0;
|
|
92 |
}
|
|
93 |
|
|
94 |
// core crypt code. OFB style, so works for both encryption and decryption
|
7043
|
95 |
private void crypt(byte[] in, int inOfs, int inLen, byte[] out,
|
|
96 |
int outOfs) {
|
2
|
97 |
if (is < 0) {
|
|
98 |
// doFinal() was called, need to reset the cipher to initial state
|
|
99 |
init(lastKey);
|
|
100 |
}
|
|
101 |
while (inLen-- > 0) {
|
|
102 |
is = (is + 1) & 0xff;
|
|
103 |
int Si = S[is];
|
|
104 |
js = (js + Si) & 0xff;
|
|
105 |
int Sj = S[js];
|
|
106 |
S[is] = Sj;
|
|
107 |
S[js] = Si;
|
|
108 |
out[outOfs++] = (byte)(in[inOfs++] ^ S[(Si + Sj) & 0xff]);
|
|
109 |
}
|
|
110 |
}
|
|
111 |
|
|
112 |
// Modes do not make sense with stream ciphers, but allow ECB
|
|
113 |
// see JCE spec.
|
|
114 |
protected void engineSetMode(String mode) throws NoSuchAlgorithmException {
|
|
115 |
if (mode.equalsIgnoreCase("ECB") == false) {
|
|
116 |
throw new NoSuchAlgorithmException("Unsupported mode " + mode);
|
|
117 |
}
|
|
118 |
}
|
|
119 |
|
|
120 |
// Padding does not make sense with stream ciphers, but allow NoPadding
|
|
121 |
// see JCE spec.
|
|
122 |
protected void engineSetPadding(String padding)
|
|
123 |
throws NoSuchPaddingException {
|
|
124 |
if (padding.equalsIgnoreCase("NoPadding") == false) {
|
|
125 |
throw new NoSuchPaddingException("Padding must be NoPadding");
|
|
126 |
}
|
|
127 |
}
|
|
128 |
|
|
129 |
// Return 0 to indicate stream cipher
|
|
130 |
// see JCE spec.
|
|
131 |
protected int engineGetBlockSize() {
|
|
132 |
return 0;
|
|
133 |
}
|
|
134 |
|
|
135 |
// output length is always the same as input length
|
|
136 |
// see JCE spec
|
|
137 |
protected int engineGetOutputSize(int inputLen) {
|
|
138 |
return inputLen;
|
|
139 |
}
|
|
140 |
|
|
141 |
// no IV, return null
|
|
142 |
// see JCE spec
|
|
143 |
protected byte[] engineGetIV() {
|
|
144 |
return null;
|
|
145 |
}
|
|
146 |
|
|
147 |
// no parameters
|
|
148 |
// see JCE spec
|
|
149 |
protected AlgorithmParameters engineGetParameters() {
|
|
150 |
return null;
|
|
151 |
}
|
|
152 |
|
|
153 |
// see JCE spec
|
|
154 |
protected void engineInit(int opmode, Key key, SecureRandom random)
|
|
155 |
throws InvalidKeyException {
|
|
156 |
init(opmode, key);
|
|
157 |
}
|
|
158 |
|
|
159 |
// see JCE spec
|
|
160 |
protected void engineInit(int opmode, Key key,
|
|
161 |
AlgorithmParameterSpec params, SecureRandom random)
|
|
162 |
throws InvalidKeyException, InvalidAlgorithmParameterException {
|
|
163 |
if (params != null) {
|
|
164 |
throw new InvalidAlgorithmParameterException
|
|
165 |
("Parameters not supported");
|
|
166 |
}
|
|
167 |
init(opmode, key);
|
|
168 |
}
|
|
169 |
|
|
170 |
// see JCE spec
|
|
171 |
protected void engineInit(int opmode, Key key,
|
|
172 |
AlgorithmParameters params, SecureRandom random)
|
|
173 |
throws InvalidKeyException, InvalidAlgorithmParameterException {
|
|
174 |
if (params != null) {
|
|
175 |
throw new InvalidAlgorithmParameterException
|
|
176 |
("Parameters not supported");
|
|
177 |
}
|
|
178 |
init(opmode, key);
|
|
179 |
}
|
|
180 |
|
|
181 |
// init method. Check opmode and key, then call init(byte[]).
|
|
182 |
private void init(int opmode, Key key) throws InvalidKeyException {
|
|
183 |
if ((opmode < Cipher.ENCRYPT_MODE) || (opmode > Cipher.UNWRAP_MODE)) {
|
|
184 |
throw new InvalidKeyException("Unknown opmode: " + opmode);
|
|
185 |
}
|
|
186 |
lastKey = getEncodedKey(key);
|
|
187 |
init(lastKey);
|
|
188 |
}
|
|
189 |
|
|
190 |
// return the encoding of key if key is a valid ARCFOUR key.
|
|
191 |
// otherwise, throw an InvalidKeyException
|
|
192 |
private static byte[] getEncodedKey(Key key) throws InvalidKeyException {
|
|
193 |
String keyAlg = key.getAlgorithm();
|
|
194 |
if (!keyAlg.equals("RC4") && !keyAlg.equals("ARCFOUR")) {
|
|
195 |
throw new InvalidKeyException("Not an ARCFOUR key: " + keyAlg);
|
|
196 |
}
|
|
197 |
if ("RAW".equals(key.getFormat()) == false) {
|
|
198 |
throw new InvalidKeyException("Key encoding format must be RAW");
|
|
199 |
}
|
|
200 |
byte[] encodedKey = key.getEncoded();
|
|
201 |
if ((encodedKey.length < 5) || (encodedKey.length > 128)) {
|
|
202 |
throw new InvalidKeyException
|
|
203 |
("Key length must be between 40 and 1024 bit");
|
|
204 |
}
|
|
205 |
return encodedKey;
|
|
206 |
}
|
|
207 |
|
|
208 |
// see JCE spec
|
|
209 |
protected byte[] engineUpdate(byte[] in, int inOfs, int inLen) {
|
|
210 |
byte[] out = new byte[inLen];
|
|
211 |
crypt(in, inOfs, inLen, out, 0);
|
|
212 |
return out;
|
|
213 |
}
|
|
214 |
|
|
215 |
// see JCE spec
|
|
216 |
protected int engineUpdate(byte[] in, int inOfs, int inLen,
|
|
217 |
byte[] out, int outOfs) throws ShortBufferException {
|
|
218 |
if (out.length - outOfs < inLen) {
|
|
219 |
throw new ShortBufferException("Output buffer too small");
|
|
220 |
}
|
|
221 |
crypt(in, inOfs, inLen, out, outOfs);
|
|
222 |
return inLen;
|
|
223 |
}
|
|
224 |
|
|
225 |
// see JCE spec
|
|
226 |
protected byte[] engineDoFinal(byte[] in, int inOfs, int inLen) {
|
|
227 |
byte[] out = engineUpdate(in, inOfs, inLen);
|
|
228 |
is = -1;
|
|
229 |
return out;
|
|
230 |
}
|
|
231 |
|
|
232 |
// see JCE spec
|
|
233 |
protected int engineDoFinal(byte[] in, int inOfs, int inLen,
|
|
234 |
byte[] out, int outOfs) throws ShortBufferException {
|
|
235 |
int outLen = engineUpdate(in, inOfs, inLen, out, outOfs);
|
|
236 |
is = -1;
|
|
237 |
return outLen;
|
|
238 |
}
|
|
239 |
|
|
240 |
// see JCE spec
|
|
241 |
protected byte[] engineWrap(Key key) throws IllegalBlockSizeException,
|
|
242 |
InvalidKeyException {
|
|
243 |
byte[] encoded = key.getEncoded();
|
|
244 |
if ((encoded == null) || (encoded.length == 0)) {
|
|
245 |
throw new InvalidKeyException("Could not obtain encoded key");
|
|
246 |
}
|
|
247 |
return engineDoFinal(encoded, 0, encoded.length);
|
|
248 |
}
|
|
249 |
|
|
250 |
// see JCE spec
|
|
251 |
protected Key engineUnwrap(byte[] wrappedKey, String algorithm,
|
|
252 |
int type) throws InvalidKeyException, NoSuchAlgorithmException {
|
|
253 |
byte[] encoded = engineDoFinal(wrappedKey, 0, wrappedKey.length);
|
|
254 |
return ConstructKeys.constructKey(encoded, algorithm, type);
|
|
255 |
}
|
|
256 |
|
|
257 |
// see JCE spec
|
|
258 |
protected int engineGetKeySize(Key key) throws InvalidKeyException {
|
|
259 |
byte[] encodedKey = getEncodedKey(key);
|
|
260 |
return encodedKey.length << 3;
|
|
261 |
}
|
|
262 |
|
|
263 |
}
|