001/* CipherSpi.java -- The cipher service provider interface.
002   Copyright (C) 2004, 2006  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.crypto;
040
041import java.nio.ByteBuffer;
042
043import java.security.AlgorithmParameters;
044import java.security.InvalidAlgorithmParameterException;
045import java.security.InvalidKeyException;
046import java.security.Key;
047import java.security.NoSuchAlgorithmException;
048import java.security.SecureRandom;
049import java.security.spec.AlgorithmParameterSpec;
050
051/**
052 * <p>This class represents the <i>Service Provider Interface</i>
053 * (<b>SPI</b>) for cryptographic ciphers.</p>
054 *
055 * <p>Providers of cryptographic ciphers must subclass this for every
056 * cipher they implement, implementing the abstract methods as
057 * appropriate, then provide an entry that points to the subclass in
058 * their implementation of {@link java.security.Provider}.</p>
059 *
060 * <p>CipherSpi objects are instantiated along with {@link Cipher}s when
061 * the {@link Cipher#getInstance(java.lang.String)} methods are invoked.
062 * Particular ciphers are referenced by a <i>transformation</i>, which
063 * is a String consisting of the cipher's name or the ciper's name
064 * followed by a mode and a padding. Transformations all follow the
065 * general form:</p>
066 *
067 * <ul>
068 * <li><i>algorithm</i>, or</li>
069 * <li><i>algorithm</i>/<i>mode</i>/<i>padding</i>
070 * </ul>
071 *
072 * <p>Cipher names in the master {@link java.security.Provider} class
073 * may be:</p>
074 *
075 * <ol>
076 * <li>The algorithm's name, which uses a pluggable mode and padding:
077 * <code>Cipher.<i>algorithm</i></code></li>
078 * <li>The algorithm's name and the mode, which uses pluggable padding:
079 * <code>Cipher.<i>algorithm</i>/<i>mode</i></code></li>
080 * <li>The algorithm's name and the padding, which uses a pluggable
081 * mode: <code>Cipher.<i>algorithm</i>//<i>padding</i></code></li>
082 * <li>The algorihtm's name, the mode, and the padding:
083 * <code>Cipher.<i>algorithm</i>/<i>mode</i>/<i>padding</i></code></li>
084 * </ol>
085 *
086 * <p>When any {@link Cipher#getInstance(java.lang.String)} method is
087 * invoked, the following happens if the transformation is simply
088 * <i>algorithm</i>:</p>
089 *
090 * <ol>
091 * <li>If the provider defines a <code>CipherSpi</code> implementation
092 * for "<i>algorithm</i>", return it. Otherwise throw a {@link
093 * java.security.NoSuchAlgorithmException}.</li>
094 * </ol>
095 *
096 * <p>If the transformation is of the form
097 * <i>algorithm</i>/<i>mode</i>/<i>padding</i>:</p>
098 *
099 * <ol>
100 * <li>If the provider defines a <code>CipherSpi</code> subclass for
101 * "<i>algorithm</i>/<i>mode</i>/<i>padding</i>", return it. Otherwise
102 * go to step 2.</li>
103 *
104 * <li>If the provider defines a <code>CipherSpi</code> subclass for
105 * "<i>algorithm</i>/<i>mode</i>", instatiate it, call {@link
106 * #engineSetPadding(java.lang.String)} for the padding name, and return
107 * it. Otherwise go to step 3.</li>
108 *
109 * <li>If the provider defines a <code>CipherSpi</code> subclass for
110 * "<i>algorithm</i>//<i>padding</i>", instatiate it, call {@link
111 * #engineSetMode(java.lang.String)} for the mode name, and return
112 * it. Otherwise go to step 4.</li>
113 *
114 * <li>If the provider defines a <code>CipherSpi</code> subclass for
115 * "<i>algorithm</i>", instatiate it, call {@link
116 * #engineSetMode(java.lang.String)} for the mode name, call {@link
117 * #engineSetPadding(java.lang.String)} for the padding name, and return
118 * it. Otherwise throw a {@link java.security.NoSuchAlgorithmException}.</li>
119 * </ol>
120 *
121 * @author Casey Marshall (csm@gnu.org)
122 * @since 1.4
123 */
124public abstract class CipherSpi
125{
126
127  // Constructors.
128  // ------------------------------------------------------------------------
129
130  /**
131   * Create a new CipherSpi.
132   */
133  public CipherSpi()
134  {
135  }
136
137  // Abstract methods to be implemented by providers.
138  // ------------------------------------------------------------------------
139
140  /**
141   * Finishes a multi-part transformation or transforms a portion of a
142   * byte array, and returns the transformed bytes.
143   *
144   * @param input       The input bytes.
145   * @param inputOffset The index in the input at which to start.
146   * @param inputLength The number of bytes to transform.
147   * @return The transformed bytes in a new array.
148   * @throws javax.crypto.IllegalBlockSizeException If this instance has
149   *         no padding and the input size is not a multiple of the
150   *         block size.
151   * @throws javax.crypto.BadPaddingException If this instance is being
152   *         used for decryption and the padding is not appropriate for
153   *         this instance's padding scheme.
154   */
155  protected abstract byte[]
156  engineDoFinal(byte[] input, int inputOffset, int inputLength)
157  throws IllegalBlockSizeException, BadPaddingException;
158
159  /**
160   * Finishes a multi-part transformation or transforms a portion of a
161   * byte array, and stores the transformed bytes in the supplied array.
162   *
163   * @param input        The input bytes.
164   * @param inputOffset  The index in the input at which to start.
165   * @param inputLength  The number of bytes to transform.
166   * @param output       The output byte array.
167   * @param outputOffset The index in the output array at which to start.
168   * @return The number of transformed bytes stored in the output array.
169   * @throws javax.crypto.IllegalBlockSizeException If this instance has
170   *         no padding and the input size is not a multiple of the
171   *         block size.
172   * @throws javax.crypto.BadPaddingException If this instance is being
173   *         used for decryption and the padding is not appropriate for
174   *         this instance's padding scheme.
175   * @throws javax.crypto.ShortBufferException If there is not enough
176   *         space in the output array for the transformed bytes.
177   */
178  protected abstract int
179  engineDoFinal(byte[] input, int inputOffset, int inputLength,
180                byte[] output, int outputOffset)
181  throws IllegalBlockSizeException, BadPaddingException, ShortBufferException;
182
183  /**
184   * @since 1.5
185   */
186  protected int engineDoFinal (ByteBuffer input, ByteBuffer output)
187    throws BadPaddingException, IllegalBlockSizeException,
188           ShortBufferException
189  {
190    int total = 0;
191    byte[] inbuf = new byte[256];
192    while (input.hasRemaining ())
193      {
194        int in = Math.min (inbuf.length, input.remaining ());
195        input.get (inbuf, 0, in);
196        byte[] outbuf = new byte[engineGetOutputSize (in)];
197        int out = 0;
198        if (input.hasRemaining ()) // i.e., we have more 'update' calls
199          out = engineUpdate (inbuf, 0, in, outbuf, 0);
200        else
201          out = engineDoFinal (inbuf, 0, in, outbuf, 0);
202        output.put (outbuf, 0, out);
203        total += out;
204      }
205    return total;
206  }
207
208  /**
209   * Returns the block size of the underlying cipher.
210   *
211   * @return The block size.
212   */
213  protected abstract int engineGetBlockSize();
214
215  /**
216   * Returns the initializaiton vector this cipher was initialized with,
217   * if any.
218   *
219   * @return The IV, or null if this cipher uses no IV or if this
220   *         instance has not been initialized yet.
221   */
222  protected abstract byte[] engineGetIV();
223
224  /**
225   * <p>Return the length of the given key in bits.</p>
226   *
227   * <p>For compatibility this method is not declared
228   * <code>abstract</code>, and the default implementation will throw an
229   * {@link java.lang.UnsupportedOperationException}. Concrete
230   * subclasses should override this method to return the correct
231   * value.</p>
232   *
233   * @param key The key to get the size for.
234   * @return The size of the key, in bits.
235   * @throws java.security.InvalidKeyException If the key's length
236   *         cannot be determined by this implementation.
237   */
238  protected int engineGetKeySize(Key key) throws InvalidKeyException
239  {
240    throw new UnsupportedOperationException();
241  }
242
243  /**
244   * <p>Returns the size, in bytes, an output buffer must be for a call
245   * to {@link #engineUpdate(byte[],int,int,byte[],int)} or {@link
246   * #engineDoFinal(byte[],int,int,byte[],int)} to succeed.</p>
247   *
248   * <p>The actual output length may be smaller than the value returned
249   * by this method, as it considers the padding length as well. The
250   * length considered is the argument plus the length of any buffered,
251   * unprocessed bytes.</p>
252   *
253   * @param inputLength The input length, in bytes.
254   * @return The size an output buffer must be.
255   */
256  protected abstract int engineGetOutputSize(int inputLength);
257
258  /**
259   * Returns the parameters that this cipher is using. This may be the
260   * parameters used to initialize this cipher, or it may be parameters
261   * that have been initialized with random values.
262   *
263   * @return This cipher's parameters, or <code>null</code> if this
264   *         cipher does not use parameters.
265   */
266  protected abstract AlgorithmParameters engineGetParameters();
267
268  /**
269   * Initializes this cipher with an operation mode, key, and source of
270   * randomness. If this cipher requires any other initializing data,
271   * for example an initialization vector, then it should generate it
272   * from the provided source of randomness.
273   *
274   * @param opmode The operation mode, one of {@link
275   *        Cipher#DECRYPT_MODE}, {@link Cipher#ENCRYPT_MODE}, {@link
276   *        Cipher#UNWRAP_MODE}, or {@link Cipher#WRAP_MODE}.
277   * @param key    The key to initialize this cipher with.
278   * @param random The source of random bytes to use.
279   * @throws java.security.InvalidKeyException If the given key is not
280   *         acceptable for this implementation.
281   */
282  protected abstract void engineInit(int opmode, Key key, SecureRandom random)
283  throws InvalidKeyException;
284
285  /**
286   * Initializes this cipher with an operation mode, key, parameters,
287   * and source of randomness. If this cipher requires any other
288   * initializing data, for example an initialization vector, then it should
289   * generate it from the provided source of randomness.
290   *
291   * @param opmode The operation mode, one of {@link
292   *        Cipher#DECRYPT_MODE}, {@link Cipher#ENCRYPT_MODE}, {@link
293   *        Cipher#UNWRAP_MODE}, or {@link Cipher#WRAP_MODE}.
294   * @param key    The key to initialize this cipher with.
295   * @param params The algorithm parameters to initialize with.
296   * @param random The source of random bytes to use.
297   * @throws java.security.InvalidAlgorithmParameterException If the
298   *         given parameters are not appropriate for this
299   *         implementation.
300   * @throws java.security.InvalidKeyException If the given key is not
301   *         acceptable for this implementation.
302   */
303  protected abstract void
304  engineInit(int opmode, Key key, AlgorithmParameters params,
305             SecureRandom random)
306  throws InvalidAlgorithmParameterException, InvalidKeyException;
307
308  /**
309   * Initializes this cipher with an operation mode, key, parameters,
310   * and source of randomness. If this cipher requires any other
311   * initializing data, for example an initialization vector, then it should
312   * generate it from the provided source of randomness.
313   *
314   * @param opmode The operation mode, one of {@link
315   *        Cipher#DECRYPT_MODE}, {@link Cipher#ENCRYPT_MODE}, {@link
316   *        Cipher#UNWRAP_MODE}, or {@link Cipher#WRAP_MODE}.
317   * @param key    The key to initialize this cipher with.
318   * @param params The algorithm parameters to initialize with.
319   * @param random The source of random bytes to use.
320   * @throws java.security.InvalidAlgorithmParameterException If the
321   *         given parameters are not appropriate for this
322   *         implementation.
323   * @throws java.security.InvalidKeyException If the given key is not
324   *         acceptable for this implementation.
325   */
326  protected abstract void
327  engineInit(int opmode, Key key, AlgorithmParameterSpec params,
328             SecureRandom random)
329  throws InvalidAlgorithmParameterException, InvalidKeyException;
330
331  /**
332   * Set the mode in which this cipher is to run.
333   *
334   * @param mode The name of the mode to use.
335   * @throws java.security.NoSuchAlgorithmException If the mode is
336   *         not supported by this cipher's provider.
337   */
338  protected abstract void engineSetMode(String mode)
339  throws NoSuchAlgorithmException;
340
341  /**
342   * Set the method with which the input is to be padded.
343   *
344   * @param padding The name of the padding to use.
345   * @throws javax.crypto.NoSuchPaddingException If the padding is not
346   *         supported by this cipher's provider.
347   */
348  protected abstract void engineSetPadding(String padding)
349  throws NoSuchPaddingException;
350
351  /**
352   * <p>Unwraps a previously-wrapped key.</p>
353   *
354   * <p>For compatibility this method is not declared
355   * <code>abstract</code>, and the default implementation will throw an
356   * {@link java.lang.UnsupportedOperationException}.</p>
357   *
358   * @param wrappedKey          The wrapped key.
359   * @param wrappedKeyAlgorithm The name of the algorithm used to wrap
360   *                            this key.
361   * @param wrappedKeyType      The type of wrapped key; one of
362   *                            {@link Cipher#PRIVATE_KEY},
363   *                            {@link Cipher#PUBLIC_KEY}, or
364   *                            {@link Cipher#SECRET_KEY}.
365   * @return The unwrapped key.
366   * @throws java.security.InvalidKeyException If the key cannot be
367   *         unwrapped, or if <code>wrappedKeyType</code> is an
368   *         inappropriate type for the unwrapped key.
369   * @throws java.security.NoSuchAlgorithmException If the
370   *         <code>wrappedKeyAlgorithm</code> is unknown.
371   */
372  protected Key engineUnwrap(byte[] wrappedKey, String wrappedKeyAlgorithm,
373                             int wrappedKeyType)
374  throws InvalidKeyException, NoSuchAlgorithmException
375  {
376    throw new UnsupportedOperationException();
377  }
378
379  /**
380   * Continue with a multi-part transformation, returning a new array of
381   * the transformed bytes.
382   *
383   * @param input       The next input bytes.
384   * @param inputOffset The index in the input array from which to start.
385   * @param inputLength The number of bytes to input.
386   * @return The transformed bytes.
387   */
388  protected abstract byte[]
389  engineUpdate(byte[] input, int inputOffset, int inputLength);
390
391  /**
392   * Continue with a multi-part transformation, storing the transformed
393   * bytes into the specified array.
394   *
395   * @param input        The next input bytes.
396   * @param inputOffset  The index in the input from which to start.
397   * @param inputLength  The number of bytes to input.
398   * @param output       The output buffer.
399   * @param outputOffset The index in the output array from which to start.
400   * @return The transformed bytes.
401   * @throws javax.crypto.ShortBufferException If there is not enough
402   *         space in the output array to store the transformed bytes.
403   */
404  protected abstract int
405  engineUpdate(byte[] input, int inputOffset, int inputLength,
406               byte[] output, int outputOffset)
407  throws ShortBufferException;
408
409  /**
410   * @since 1.5
411   */
412  protected int engineUpdate (ByteBuffer input, ByteBuffer output)
413    throws ShortBufferException
414  {
415    int total = 0;
416    byte[] inbuf = new byte[256];
417    while (input.hasRemaining ())
418      {
419        int in = Math.min (inbuf.length, input.remaining ());
420        input.get (inbuf, 0, in);
421        byte[] outbuf = new byte[engineGetOutputSize (in)];
422        int out = engineUpdate (inbuf, 0, in, outbuf, 0);
423        output.put (outbuf, 0, out);
424        total += out;
425      }
426    return total;
427  }
428
429  /**
430   * <p>Wrap a key.</p>
431   *
432   * <p>For compatibility this method is not declared
433   * <code>abstract</code>, and the default implementation will throw an
434   * {@link java.lang.UnsupportedOperationException}.</p>
435   *
436   * @param key The key to wrap.
437   * @return The wrapped key.
438   * @throws java.security.InvalidKeyException If the key cannot be
439   *         wrapped.
440   */
441  protected byte[] engineWrap(Key key) throws InvalidKeyException, IllegalBlockSizeException
442  {
443    throw new UnsupportedOperationException();
444  }
445}