SignatureSpi


1   /*
2    * @(#)SignatureSpi.java    1.24 04/05/18
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7     
8   package java.security;
9   
10  import java.security.spec.AlgorithmParameterSpec  ;
11  import java.util.*;
12  import java.io.*;
13  
14  import java.nio.ByteBuffer  ;
15  
16  import sun.security.jca.JCAUtil;
17  
18  /**
19   * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
20   * for the <code>Signature</code> class, which is used to provide the
21   * functionality of a digital signature algorithm. Digital signatures are used
22   * for authentication and integrity assurance of digital data.
23   *.
24   * <p> All the abstract methods in this class must be implemented by each
25   * cryptographic service provider who wishes to supply the implementation
26   * of a particular signature algorithm.
27   *
28   * @author Benjamin Renaud 
29   *
30   * @version 1.24, 05/18/04
31   *
32   * @see Signature
33   */
34  
35  public abstract class SignatureSpi {
36  
37      /**
38       * Application-specified source of randomness. 
39       */
40      protected SecureRandom   appRandom = null;
41  
42      /**
43       * Initializes this signature object with the specified
44       * public key for verification operations.
45       *
46       * @param publicKey the public key of the identity whose signature is
47       * going to be verified.
48       * 
49       * @exception InvalidKeyException if the key is improperly
50       * encoded, parameters are missing, and so on.  
51       */
52      protected abstract void engineInitVerify(PublicKey   publicKey)
53      throws InvalidKeyException  ;
54  
55      /**
56       * Initializes this signature object with the specified
57       * private key for signing operations.
58       *
59       * @param privateKey the private key of the identity whose signature
60       * will be generated.
61       *
62       * @exception InvalidKeyException if the key is improperly
63       * encoded, parameters are missing, and so on. 
64       */
65      protected abstract void engineInitSign(PrivateKey   privateKey)
66      throws InvalidKeyException  ;
67  
68      /**
69       * Initializes this signature object with the specified
70       * private key and source of randomness for signing operations.
71       *
72       * <p>This concrete method has been added to this previously-defined
73       * abstract class. (For backwards compatibility, it cannot be abstract.)
74       *
75       * @param privateKey the private key of the identity whose signature
76       * will be generated.
77       * @param random the source of randomness
78       *
79       * @exception InvalidKeyException if the key is improperly
80       * encoded, parameters are missing, and so on. 
81       */
82      protected void engineInitSign(PrivateKey   privateKey,
83                    SecureRandom   random)
84      throws InvalidKeyException   {
85          this.appRandom = random;
86          engineInitSign(privateKey);
87      }
88  
89      /**
90       * Updates the data to be signed or verified
91       * using the specified byte.
92       *
93       * @param b the byte to use for the update.
94       *
95       * @exception SignatureException if the engine is not initialized
96       * properly.
97       */
98      protected abstract void engineUpdate(byte b) throws SignatureException  ;
99  
100     /**
101      * Updates the data to be signed or verified, using the 
102      * specified array of bytes, starting at the specified offset.
103      *
104      * @param b the array of bytes  
105      * @param off the offset to start from in the array of bytes 
106      * @param len the number of bytes to use, starting at offset
107      *
108      * @exception SignatureException if the engine is not initialized 
109      * properly
110      */
111     protected abstract void engineUpdate(byte[] b, int off, int len) 
112         throws SignatureException  ;
113 
114     /**
115      * Updates the data to be signed or verified using the specified
116      * ByteBuffer. Processes the <code>data.remaining()</code> bytes
117      * starting at at <code>data.position()</code>.
118      * Upon return, the buffer's position will be equal to its limit;
119      * its limit will not have changed.
120      *
121      * @param input the ByteBuffer
122      * @since 1.5
123      */
124     protected void engineUpdate(ByteBuffer   input) {
125     if (input.hasRemaining() == false) {
126         return;
127     }
128     try {
129         if (input.hasArray()) {
130         byte[] b = input.array();
131         int ofs = input.arrayOffset();
132         int pos = input.position();
133         int lim = input.limit();
134         engineUpdate(b, ofs + pos, lim - pos);
135         input.position(lim);
136         } else {
137         int len = input.remaining();
138         byte[] b = new byte[JCAUtil.getTempArraySize(len)];
139         while (len > 0) {
140             int chunk = Math.min(len, b.length);
141             input.get(b, 0, chunk);
142             engineUpdate(b, 0, chunk);
143             len -= chunk;
144         }
145         }
146     } catch (SignatureException   e) {
147         // is specified to only occur when the engine is not initialized
148         // this case should never occur as it is caught in Signature.java
149         throw new ProviderException  ("update() failed", e);
150     }
151     }
152 
153     /** 
154      * Returns the signature bytes of all the data
155      * updated so far.    
156      * The format of the signature depends on the underlying 
157      * signature scheme.
158      *
159      * @return the signature bytes of the signing operation's result.
160      *
161      * @exception SignatureException if the engine is not
162      * initialized properly or if this signature algorithm is unable to
163      * process the input data provided.
164      */
165     protected abstract byte[] engineSign() throws SignatureException  ;
166 
167     /**
168      * Finishes this signature operation and stores the resulting signature
169      * bytes in the provided buffer <code>outbuf</code>, starting at
170      * <code>offset</code>.
171      * The format of the signature depends on the underlying 
172      * signature scheme.
173      * 
174      * <p>The signature implementation is reset to its initial state
175      * (the state it was in after a call to one of the
176      * <code>engineInitSign</code> methods)
177      * and can be reused to generate further signatures with the same private
178      * key.
179      *
180      * This method should be abstract, but we leave it concrete for
181      * binary compatibility.  Knowledgeable providers should override this
182      * method.
183      *
184      * @param outbuf buffer for the signature result.
185      *
186      * @param offset offset into <code>outbuf</code> where the signature is
187      * stored.
188      *
189      * @param len number of bytes within <code>outbuf</code> allotted for the
190      * signature.
191      * Both this default implementation and the SUN provider do not
192      * return partial digests. If the value of this parameter is less
193      * than the actual signature length, this method will throw a
194      * SignatureException.
195      * This parameter is ignored if its value is greater than or equal to
196      * the actual signature length.
197      *
198      * @return the number of bytes placed into <code>outbuf</code>
199      * 
200      * @exception SignatureException if the engine is not
201      * initialized properly, if this signature algorithm is unable to
202      * process the input data provided, or if <code>len</code> is less
203      * than the actual signature length.
204      *
205      * @since 1.2
206      */
207     protected int engineSign(byte[] outbuf, int offset, int len)
208                     throws SignatureException   {
209     byte[] sig = engineSign();
210     if (len < sig.length) {
211         throw new SignatureException  
212             ("partial signatures not returned");
213     }
214     if (outbuf.length - offset < sig.length) {
215         throw new SignatureException  
216             ("insufficient space in the output buffer to store the "
217              + "signature");
218     }
219     System.arraycopy(sig, 0, outbuf, offset, sig.length);
220     return sig.length;
221     }
222 
223     /** 
224      * Verifies the passed-in signature.   
225      * 
226      * @param sigBytes the signature bytes to be verified.
227      *
228      * @return true if the signature was verified, false if not. 
229      *
230      * @exception SignatureException if the engine is not 
231      * initialized properly, the passed-in signature is improperly 
232      * encoded or of the wrong type, if this signature algorithm is unable to
233      * process the input data provided, etc.
234      */
235     protected abstract boolean engineVerify(byte[] sigBytes) 
236     throws SignatureException  ;
237 
238     /** 
239      * Verifies the passed-in signature in the specified array
240      * of bytes, starting at the specified offset.
241      *
242      * <p> Note: Subclasses should overwrite the default implementation.
243      *
244      * 
245      * @param sigBytes the signature bytes to be verified.
246      * @param offset the offset to start from in the array of bytes.
247      * @param length the number of bytes to use, starting at offset.
248      *
249      * @return true if the signature was verified, false if not. 
250      *
251      * @exception SignatureException if the engine is not 
252      * initialized properly, the passed-in signature is improperly 
253      * encoded or of the wrong type, if this signature algorithm is unable to
254      * process the input data provided, etc.
255      */
256     protected boolean engineVerify(byte[] sigBytes, int offset, int length) 
257     throws SignatureException   {
258     byte[] sigBytesCopy = new byte[length];
259     System.arraycopy(sigBytes, offset, sigBytesCopy, 0, length);
260     return engineVerify(sigBytesCopy);
261     }
262 
263     /**
264      * Sets the specified algorithm parameter to the specified
265      * value. This method supplies a general-purpose mechanism through
266      * which it is possible to set the various parameters of this object. 
267      * A parameter may be any settable parameter for the algorithm, such as 
268      * a parameter size, or a source of random bits for signature generation 
269      * (if appropriate), or an indication of whether or not to perform
270      * a specific but optional computation. A uniform algorithm-specific 
271      * naming scheme for each parameter is desirable but left unspecified 
272      * at this time.
273      *
274      * @param param the string identifier of the parameter.
275      *
276      * @param value the parameter value.
277      *
278      * @exception InvalidParameterException if <code>param</code> is an
279      * invalid parameter for this signature algorithm engine,
280      * the parameter is already set
281      * and cannot be set again, a security exception occurs, and so on. 
282      *
283      * @deprecated Replaced by {@link 
284      * #engineSetParameter(java.security.spec.AlgorithmParameterSpec)
285      * engineSetParameter}.
286      */
287     @Deprecated  
288     protected abstract void engineSetParameter(String   param, Object   value) 
289     throws InvalidParameterException  ;
290 
291     /**
292      * <p>This method is overridden by providers to initialize
293      * this signature engine with the specified parameter set.
294      *
295      * @param params the parameters
296      *
297      * @exception UnsupportedOperationException if this method is not
298      * overridden by a provider
299      *
300      * @exception InvalidAlgorithmParameterException if this method is
301      * overridden by a provider and the the given parameters
302      * are inappropriate for this signature engine
303      */
304     protected void engineSetParameter(AlgorithmParameterSpec   params)
305     throws InvalidAlgorithmParameterException   {
306         throw new UnsupportedOperationException  ();
307     }
308 
309     /**
310      * <p>This method is overridden by providers to return the
311      * parameters used with this signature engine, or null 
312      * if this signature engine does not use any parameters.
313      *
314      * <p>The returned parameters may be the same that were used to initialize
315      * this signature engine, or may contain a combination of default and 
316      * randomly generated parameter values used by the underlying signature
317      * implementation if this signature engine requires algorithm parameters 
318      * but was not initialized with any.
319      * 
320      * @return the parameters used with this signature engine, or null if this
321      * signature engine does not use any parameters
322      *
323      * @exception UnsupportedOperationException if this method is
324      * not overridden by a provider
325      */
326     protected AlgorithmParameters   engineGetParameters() {
327     throw new UnsupportedOperationException  ();
328     }
329 
330     /**
331      * Gets the value of the specified algorithm parameter. 
332      * This method supplies a general-purpose mechanism through which it 
333      * is possible to get the various parameters of this object. A parameter
334      * may be any settable parameter for the algorithm, such as a parameter 
335      * size, or  a source of random bits for signature generation (if 
336      * appropriate), or an indication of whether or not to perform a 
337      * specific but optional computation. A uniform algorithm-specific 
338      * naming scheme for each parameter is desirable but left unspecified 
339      * at this time.
340      *
341      * @param param the string name of the parameter.
342      *
343      * @return the object that represents the parameter value, or null if
344      * there is none.
345      *
346      * @exception InvalidParameterException if <code>param</code> is an 
347      * invalid parameter for this engine, or another exception occurs while
348      * trying to get this parameter.
349      *
350      * @deprecated
351      */
352     @Deprecated  
353     protected abstract Object   engineGetParameter(String   param)
354     throws InvalidParameterException  ;
355 
356     /**
357      * Returns a clone if the implementation is cloneable.
358      * 
359      * @return a clone if the implementation is cloneable.
360      *
361      * @exception CloneNotSupportedException if this is called
362      * on an implementation that does not support <code>Cloneable</code>.
363      */
364     public Object   clone() throws CloneNotSupportedException   {
365     if (this instanceof Cloneable  ) {
366         return super.clone();
367     } else {
368         throw new CloneNotSupportedException  ();
369     }
370     }
371 }
372     
373         
374 
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