Source code: javax/crypto/CipherSpi.java
1 /* CipherSpi.java -- The cipher service provider interface.
2 Copyright (C) 2004 Free Software Foundation, Inc.
3
4 This file is part of GNU Classpath.
5
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 USA.
20
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
37
38
39 package javax.crypto;
40
41 import java.security.AlgorithmParameters;
42 import java.security.InvalidAlgorithmParameterException;
43 import java.security.InvalidKeyException;
44 import java.security.Key;
45 import java.security.NoSuchAlgorithmException;
46 import java.security.SecureRandom;
47 import java.security.spec.AlgorithmParameterSpec;
48
49 /**
50 * <p>This class represents the <i>Service Provider Interface</i>
51 * (<b>SPI</b>) for cryptographic ciphers.</p>
52 *
53 * <p>Providers of cryptographic ciphers must subclass this for every
54 * cipher they implement, implementing the abstract methods as
55 * appropriate, then provide an entry that points to the subclass in
56 * their implementation of {@link java.security.Provider}.</p>
57 *
58 * <p>CipherSpi objects are instantiated along with {@link Cipher}s when
59 * the {@link Cipher#getInstance(java.lang.String)} methods are invoked.
60 * Particular ciphers are referenced by a <i>transformation</i>, which
61 * is a String consisting of the cipher's name or the ciper's name
62 * followed by a mode and a padding. Transformations all follow the
63 * general form:</p>
64 *
65 * <ul>
66 * <li><i>algorithm</i>, or</li>
67 * <li><i>algorithm</i>/<i>mode</i>/<i>padding</i>
68 * </ul>
69 *
70 * <p>Cipher names in the master {@link java.security.Provider} class
71 * may be:</p>
72 *
73 * <ol>
74 * <li>The algorithm's name, which uses a pluggable mode and padding:
75 * <code>Cipher.<i>algorithm</i></code></li>
76 * <li>The algorithm's name and the mode, which uses pluggable padding:
77 * <code>Cipher.<i>algorithm</i>/<i>mode</i></code></li>
78 * <li>The algorithm's name and the padding, which uses a pluggable
79 * mode: <code>Cipher.<i>algorithm</i>//<i>padding</i></code></li>
80 * <li>The algorihtm's name, the mode, and the padding:
81 * <code>Cipher.<i>algorithm</i>/<i>mode</i>/<i>padding</i></code></li>
82 * </ol>
83 *
84 * <p>When any {@link Cipher#getInstance(java.lang.String)} method is
85 * invoked, the following happens if the transformation is simply
86 * <i>algorithm</i>:</p>
87 *
88 * <ol>
89 * <li>If the provider defines a <code>CipherSpi</code> implementation
90 * for "<i>algorithm</i>", return it. Otherwise throw a {@link
91 * java.security.NoSuchAlgorithmException}.</li>
92 * </ol>
93 *
94 * <p>If the transformation is of the form
95 * <i>algorithm</i>/<i>mode</i>/<i>padding</i>:</p>
96 *
97 * <ol>
98 * <li>If the provider defines a <code>CipherSpi</code> subclass for
99 * "<i>algorithm</i>/<i>mode</i>/<i>padding</i>", return it. Otherwise
100 * go to step 2.</li>
101 *
102 * <li>If the provider defines a <code>CipherSpi</code> subclass for
103 * "<i>algorithm</i>/<i>mode</i>", instatiate it, call {@link
104 * #engineSetPadding(java.lang.String)} for the padding name, and return
105 * it. Otherwise go to step 3.</li>
106 *
107 * <li>If the provider defines a <code>CipherSpi</code> subclass for
108 * "<i>algorithm</i>//<i>padding</i>", instatiate it, call {@link
109 * #engineSetMode(java.lang.String)} for the mode name, and return
110 * it. Otherwise go to step 4.</li>
111 *
112 * <li>If the provider defines a <code>CipherSpi</code> subclass for
113 * "<i>algorithm</i>", instatiate it, call {@link
114 * #engineSetMode(java.lang.String)} for the mode name, call {@link
115 * #engineSetPadding(java.lang.String)} for the padding name, and return
116 * it. Otherwise throw a {@link java.security.NoSuchAlgorithmException}.</li>
117 * </ol>
118 *
119 * @author Casey Marshall (csm@gnu.org)
120 * @since 1.4
121 */
122 public abstract class CipherSpi
123 {
124
125 // Constructors.
126 // ------------------------------------------------------------------------
127
128 /**
129 * Create a new CipherSpi.
130 */
131 public CipherSpi()
132 {
133 }
134
135 // Abstract methods to be implemented by providers.
136 // ------------------------------------------------------------------------
137
138 /**
139 * Finishes a multi-part transformation or transforms a portion of a
140 * byte array, and returns the transformed bytes.
141 *
142 * @param input The input bytes.
143 * @param inputOffset The index in the input at which to start.
144 * @param inputLength The number of bytes to transform.
145 * @return The transformed bytes in a new array.
146 * @throws javax.crypto.IllegalBlockSizeException If this instance has
147 * no padding and the input size is not a multiple of the
148 * block size.
149 * @throws javax.crypto.BadPaddingException If this instance is being
150 * used for decryption and the padding is not appropriate for
151 * this instance's padding scheme.
152 */
153 protected abstract byte[]
154 engineDoFinal(byte[] input, int inputOffset, int inputLength)
155 throws IllegalBlockSizeException, BadPaddingException;
156
157 /**
158 * Finishes a multi-part transformation or transforms a portion of a
159 * byte array, and stores the transformed bytes in the supplied array.
160 *
161 * @param input The input bytes.
162 * @param inputOffset The index in the input at which to start.
163 * @param inputLength The number of bytes to transform.
164 * @param output The output byte array.
165 * @param outputOffset The index in the output array at which to start.
166 * @return The number of transformed bytes stored in the output array.
167 * @throws javax.crypto.IllegalBlockSizeException If this instance has
168 * no padding and the input size is not a multiple of the
169 * block size.
170 * @throws javax.crypto.BadPaddingException If this instance is being
171 * used for decryption and the padding is not appropriate for
172 * this instance's padding scheme.
173 * @throws javax.crypto.ShortBufferException If there is not enough
174 * space in the output array for the transformed bytes.
175 */
176 protected abstract int
177 engineDoFinal(byte[] input, int inputOffset, int inputLength,
178 byte[] output, int outputOffset)
179 throws IllegalBlockSizeException, BadPaddingException, ShortBufferException;
180
181 /**
182 * Returns the block size of the underlying cipher.
183 *
184 * @return The block size.
185 */
186 protected abstract int engineGetBlockSize();
187
188 /**
189 * Returns the initializaiton vector this cipher was initialized with,
190 * if any.
191 *
192 * @return The IV, or null if this cipher uses no IV or if this
193 * instance has not been initialized yet.
194 */
195 protected abstract byte[] engineGetIV();
196
197 /**
198 * <p>Return the length of the given key in bits.</p>
199 *
200 * <p>For compatibility this method is not declared
201 * <code>abstract</code>, and the default implementation will throw an
202 * {@link java.lang.UnsupportedOperationException}. Concrete
203 * subclasses should override this method to return the correct
204 * value.</p>
205 *
206 * @param key The key to get the size for.
207 * @return The size of the key, in bits.
208 * @throws java.security.InvalidKeyException If the key's length
209 * cannot be determined by this implementation.
210 */
211 protected int engineGetKeySize(Key key) throws InvalidKeyException
212 {
213 throw new UnsupportedOperationException();
214 }
215
216 /**
217 * <p>Returns the size, in bytes, an output buffer must be for a call
218 * to {@link #engineUpdate(byte[],int,int,byte[],int)} or {@link
219 * #engineDoFinal(byte[],int,int,byte[],int)} to succeed.</p>
220 *
221 * <p>The actual output length may be smaller than the value returned
222 * by this method, as it considers the padding length as well. The
223 * length considered is the argument plus the length of any buffered,
224 * unprocessed bytes.</p>
225 *
226 * @param inputLength The input length, in bytes.
227 * @return The size an output buffer must be.
228 */
229 protected abstract int engineGetOutputSize(int inputLength);
230
231 /**
232 * Returns the parameters that this cipher is using. This may be the
233 * parameters used to initialize this cipher, or it may be parameters
234 * that have been initialized with random values.
235 *
236 * @return This cipher's parameters, or <code>null</code> if this
237 * cipher does not use parameters.
238 */
239 protected abstract AlgorithmParameters engineGetParameters();
240
241 /**
242 * Initializes this cipher with an operation mode, key, and source of
243 * randomness. If this cipher requires any other initializing data,
244 * for example an initialization vector, then it should generate it
245 * from the provided source of randomness.
246 *
247 * @param opmode The operation mode, one of {@link
248 * Cipher#DECRYPT_MODE}, {@link Cipher#ENCRYPT_MODE}, {@link
249 * Cipher#UNWRAP_MODE}, or {@link Cipher#WRAP_MODE}.
250 * @param key The key to initialize this cipher with.
251 * @param random The source of random bytes to use.
252 * @throws java.security.InvalidKeyException If the given key is not
253 * acceptable for this implementation.
254 */
255 protected abstract void engineInit(int opmode, Key key, SecureRandom random)
256 throws InvalidKeyException;
257
258 /**
259 * Initializes this cipher with an operation mode, key, parameters,
260 * and source of randomness. If this cipher requires any other
261 * initializing data, for example an initialization vector, then it should
262 * generate it from the provided source of randomness.
263 *
264 * @param opmode The operation mode, one of {@link
265 * Cipher#DECRYPT_MODE}, {@link Cipher#ENCRYPT_MODE}, {@link
266 * Cipher#UNWRAP_MODE}, or {@link Cipher#WRAP_MODE}.
267 * @param key The key to initialize this cipher with.
268 * @param params The algorithm parameters to initialize with.
269 * @param random The source of random bytes to use.
270 * @throws java.security.InvalidAlgorithmParameterException If the
271 * given parameters are not appropriate for this
272 * implementation.
273 * @throws java.security.InvalidKeyException If the given key is not
274 * acceptable for this implementation.
275 */
276 protected abstract void
277 engineInit(int opmode, Key key, AlgorithmParameters params,
278 SecureRandom random)
279 throws InvalidAlgorithmParameterException, InvalidKeyException;
280
281 /**
282 * Initializes this cipher with an operation mode, key, parameters,
283 * and source of randomness. If this cipher requires any other
284 * initializing data, for example an initialization vector, then it should
285 * generate it from the provided source of randomness.
286 *
287 * @param opmode The operation mode, one of {@link
288 * Cipher#DECRYPT_MODE}, {@link Cipher#ENCRYPT_MODE}, {@link
289 * Cipher#UNWRAP_MODE}, or {@link Cipher#WRAP_MODE}.
290 * @param key The key to initialize this cipher with.
291 * @param params The algorithm parameters to initialize with.
292 * @param random The source of random bytes to use.
293 * @throws java.security.InvalidAlgorithmParameterException If the
294 * given parameters are not appropriate for this
295 * implementation.
296 * @throws java.security.InvalidKeyException If the given key is not
297 * acceptable for this implementation.
298 */
299 protected abstract void
300 engineInit(int opmode, Key key, AlgorithmParameterSpec params,
301 SecureRandom random)
302 throws InvalidAlgorithmParameterException, InvalidKeyException;
303
304 /**
305 * Set the mode in which this cipher is to run.
306 *
307 * @param mode The name of the mode to use.
308 * @throws java.security.NoSuchAlgorithmException If the mode is
309 * not supported by this cipher's provider.
310 */
311 protected abstract void engineSetMode(String mode)
312 throws NoSuchAlgorithmException;
313
314 /**
315 * Set the method with which the input is to be padded.
316 *
317 * @param padding The name of the padding to use.
318 * @throws javax.crypto.NoSuchPaddingException If the padding is not
319 * supported by this cipher's provider.
320 */
321 protected abstract void engineSetPadding(String padding)
322 throws NoSuchPaddingException;
323
324 /**
325 * <p>Unwraps a previously-wrapped key.</p>
326 *
327 * <p>For compatibility this method is not declared
328 * <code>abstract</code>, and the default implementation will throw an
329 * {@link java.lang.UnsupportedOperationException}.</p>
330 *
331 * @param wrappedKey The wrapped key.
332 * @param wrappedKeyAlgorithm The name of the algorithm used to wrap
333 * this key.
334 * @param wrappedKeyType The type of wrapped key; one of
335 * {@link Cipher#PRIVATE_KEY},
336 * {@link Cipher#PUBLIC_KEY}, or
337 * {@link Cipher#SECRET_KEY}.
338 * @return The unwrapped key.
339 * @throws java.security.InvalidKeyException If the key cannot be
340 * unwrapped, or if <code>wrappedKeyType</code> is an
341 * inappropriate type for the unwrapped key.
342 * @throws java.security.NoSuchAlgorithmException If the
343 * <code>wrappedKeyAlgorithm</code> is unknown.
344 */
345 protected Key engineUnwrap(byte[] wrappedKey, String wrappedKeyAlgorithm,
346 int wrappedKeyType)
347 throws InvalidKeyException, NoSuchAlgorithmException
348 {
349 throw new UnsupportedOperationException();
350 }
351
352 /**
353 * Continue with a multi-part transformation, returning a new array of
354 * the transformed bytes.
355 *
356 * @param input The next input bytes.
357 * @param inputOffset The index in the input array from which to start.
358 * @param inputLength The number of bytes to input.
359 * @return The transformed bytes.
360 */
361 protected abstract byte[]
362 engineUpdate(byte[] input, int inputOffset, int inputLength);
363
364 /**
365 * Continue with a multi-part transformation, storing the transformed
366 * bytes into the specified array.
367 *
368 * @param input The next input bytes.
369 * @param inputOffset The index in the input from which to start.
370 * @param inputLength The number of bytes to input.
371 * @param output The output buffer.
372 * @param outputOffset The index in the output array from which to start.
373 * @return The transformed bytes.
374 * @throws javax.crypto.ShortBufferException If there is not enough
375 * space in the output array to store the transformed bytes.
376 */
377 protected abstract int
378 engineUpdate(byte[] input, int inputOffset, int inputLength,
379 byte[] output, int outputOffset)
380 throws ShortBufferException;
381
382 /**
383 * <p>Wrap a key.</p>
384 *
385 * <p>For compatibility this method is not declared
386 * <code>abstract</code>, and the default implementation will throw an
387 * {@link java.lang.UnsupportedOperationException}.</p>
388 *
389 * @param key The key to wrap.
390 * @return The wrapped key.
391 * @throws java.security.InvalidKeyException If the key cannot be
392 * wrapped.
393 */
394 protected byte[] engineWrap(Key key) throws InvalidKeyException, IllegalBlockSizeException
395 {
396 throw new UnsupportedOperationException();
397 }
398 }