1 /*
2 * Copyright (c) 2003, 2013, 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 sun.security.pkcs11;
27
28 import java.io.IOException;
29 import java.math.BigInteger;
30 import java.nio.ByteBuffer;
31
32 import java.security.*;
33 import java.security.interfaces.*;
34 import sun.nio.ch.DirectBuffer;
35
36 import sun.security.util.*;
37 import sun.security.x509.AlgorithmId;
38
39 import sun.security.rsa.RSASignature;
40 import sun.security.rsa.RSAPadding;
41
42 import sun.security.pkcs11.wrapper.*;
43 import static sun.security.pkcs11.wrapper.PKCS11Constants.*;
44 import sun.security.util.KeyUtil;
45
46 /**
47 * Signature implementation class. This class currently supports the
48 * following algorithms:
49 *
50 * . DSA
51 * . NONEwithDSA (RawDSA)
52 * . SHA1withDSA
53 * . RSA:
54 * . MD2withRSA
55 * . MD5withRSA
56 * . SHA1withRSA
57 * . SHA224withRSA
58 * . SHA256withRSA
59 * . SHA384withRSA
60 * . SHA512withRSA
61 * . ECDSA
62 * . NONEwithECDSA
63 * . SHA1withECDSA
64 * . SHA224withECDSA
65 * . SHA256withECDSA
66 * . SHA384withECDSA
67 * . SHA512withECDSA
68 *
69 * Note that the underlying PKCS#11 token may support complete signature
70 * algorithm (e.g. CKM_DSA_SHA1, CKM_MD5_RSA_PKCS), or it may just
71 * implement the signature algorithm without hashing (e.g. CKM_DSA, CKM_PKCS),
72 * or it may only implement the raw public key operation (CKM_RSA_X_509).
73 * This class uses what is available and adds whatever extra processing
74 * is needed.
75 *
76 * @author Andreas Sterbenz
77 * @since 1.5
78 */
79 final class P11Signature extends SignatureSpi {
80
81 // token instance
82 private final Token token;
83
84 // algorithm name
85 private final String algorithm;
86
87 // name of the key algorithm, currently either RSA or DSA
88 private final String keyAlgorithm;
89
90 // mechanism id
91 private final long mechanism;
92
93 // digest algorithm OID, if we encode RSA signature ourselves
94 private final ObjectIdentifier digestOID;
95
96 // type, one of T_* below
97 private final int type;
98
99 // key instance used, if init*() was called
100 private P11Key p11Key;
101
102 // message digest, if we do the digesting ourselves
103 private final MessageDigest md;
104
105 // associated session, if any
106 private Session session;
107
108 // mode, one of M_* below
109 private int mode;
110
111 // flag indicating whether an operation is initialized
112 private boolean initialized;
113
114 // buffer, for update(byte) or DSA
115 private final byte[] buffer;
116
117 // total number of bytes processed in current operation
118 private int bytesProcessed;
119
120 // constant for signing mode
121 private final static int M_SIGN = 1;
122 // constant for verification mode
123 private final static int M_VERIFY = 2;
124
125 // constant for type digesting, we do the hashing ourselves
126 private final static int T_DIGEST = 1;
127 // constant for type update, token does everything
128 private final static int T_UPDATE = 2;
129 // constant for type raw, used with RawDSA and NONEwithECDSA only
130 private final static int T_RAW = 3;
131
132 // XXX PKCS#11 v2.20 says "should not be longer than 1024 bits",
133 // but this is a little arbitrary
134 private final static int RAW_ECDSA_MAX = 128;
135
136 P11Signature(Token token, String algorithm, long mechanism)
137 throws NoSuchAlgorithmException, PKCS11Exception {
138 super();
139 this.token = token;
140 this.algorithm = algorithm;
141 this.mechanism = mechanism;
142 byte[] buffer = null;
143 ObjectIdentifier digestOID = null;
144 MessageDigest md = null;
145 switch ((int)mechanism) {
146 case (int)CKM_MD2_RSA_PKCS:
147 case (int)CKM_MD5_RSA_PKCS:
148 case (int)CKM_SHA1_RSA_PKCS:
149 case (int)CKM_SHA224_RSA_PKCS:
150 case (int)CKM_SHA256_RSA_PKCS:
151 case (int)CKM_SHA384_RSA_PKCS:
152 case (int)CKM_SHA512_RSA_PKCS:
153 keyAlgorithm = "RSA";
154 type = T_UPDATE;
155 buffer = new byte[1];
156 break;
157 case (int)CKM_DSA_SHA1:
158 keyAlgorithm = "DSA";
159 type = T_UPDATE;
160 buffer = new byte[1];
161 break;
162 case (int)CKM_ECDSA_SHA1:
163 keyAlgorithm = "EC";
164 type = T_UPDATE;
165 buffer = new byte[1];
166 break;
167 case (int)CKM_DSA:
168 keyAlgorithm = "DSA";
169 if (algorithm.equals("DSA")) {
170 type = T_DIGEST;
171 md = MessageDigest.getInstance("SHA-1");
172 } else if (algorithm.equals("RawDSA")) {
173 type = T_RAW;
174 buffer = new byte[20];
175 } else {
176 throw new ProviderException(algorithm);
177 }
178 break;
179 case (int)CKM_ECDSA:
180 keyAlgorithm = "EC";
181 if (algorithm.equals("NONEwithECDSA")) {
182 type = T_RAW;
183 buffer = new byte[RAW_ECDSA_MAX];
184 } else {
185 String digestAlg;
186 if (algorithm.equals("SHA1withECDSA")) {
187 digestAlg = "SHA-1";
188 } else if (algorithm.equals("SHA224withECDSA")) {
189 digestAlg = "SHA-224";
190 } else if (algorithm.equals("SHA256withECDSA")) {
191 digestAlg = "SHA-256";
192 } else if (algorithm.equals("SHA384withECDSA")) {
193 digestAlg = "SHA-384";
194 } else if (algorithm.equals("SHA512withECDSA")) {
195 digestAlg = "SHA-512";
196 } else {
197 throw new ProviderException(algorithm);
198 }
199 type = T_DIGEST;
200 md = MessageDigest.getInstance(digestAlg);
201 }
202 break;
203 case (int)CKM_RSA_PKCS:
204 case (int)CKM_RSA_X_509:
205 keyAlgorithm = "RSA";
206 type = T_DIGEST;
207 if (algorithm.equals("MD5withRSA")) {
208 md = MessageDigest.getInstance("MD5");
209 digestOID = AlgorithmId.MD5_oid;
210 } else if (algorithm.equals("SHA1withRSA")) {
211 md = MessageDigest.getInstance("SHA-1");
212 digestOID = AlgorithmId.SHA_oid;
213 } else if (algorithm.equals("MD2withRSA")) {
214 md = MessageDigest.getInstance("MD2");
215 digestOID = AlgorithmId.MD2_oid;
216 } else if (algorithm.equals("SHA224withRSA")) {
217 md = MessageDigest.getInstance("SHA-224");
218 digestOID = AlgorithmId.SHA224_oid;
219 } else if (algorithm.equals("SHA256withRSA")) {
220 md = MessageDigest.getInstance("SHA-256");
221 digestOID = AlgorithmId.SHA256_oid;
222 } else if (algorithm.equals("SHA384withRSA")) {
223 md = MessageDigest.getInstance("SHA-384");
224 digestOID = AlgorithmId.SHA384_oid;
225 } else if (algorithm.equals("SHA512withRSA")) {
226 md = MessageDigest.getInstance("SHA-512");
227 digestOID = AlgorithmId.SHA512_oid;
228 } else {
229 throw new ProviderException("Unknown signature: " + algorithm);
230 }
231 break;
232 default:
233 throw new ProviderException("Unknown mechanism: " + mechanism);
234 }
235 this.buffer = buffer;
236 this.digestOID = digestOID;
237 this.md = md;
238 }
239
240 private void ensureInitialized() {
241 token.ensureValid();
242 if (initialized == false) {
243 initialize();
244 }
245 }
246
247 private void cancelOperation() {
248 token.ensureValid();
249 if (initialized == false) {
250 return;
251 }
252 initialized = false;
253 if ((session == null) || (token.explicitCancel == false)) {
254 return;
255 }
256 if (session.hasObjects() == false) {
257 session = token.killSession(session);
258 return;
259 }
260 // "cancel" operation by finishing it
261 // XXX make sure all this always works correctly
262 if (mode == M_SIGN) {
263 try {
264 if (type == T_UPDATE) {
265 token.p11.C_SignFinal(session.id(), 0);
266 } else {
267 byte[] digest;
268 if (type == T_DIGEST) {
269 digest = md.digest();
270 } else { // T_RAW
271 digest = buffer;
272 }
273 token.p11.C_Sign(session.id(), digest);
274 }
275 } catch (PKCS11Exception e) {
276 throw new ProviderException("cancel failed", e);
277 }
278 } else { // M_VERIFY
279 try {
280 byte[] signature;
281 if (keyAlgorithm.equals("DSA")) {
282 signature = new byte[40];
283 } else {
284 signature = new byte[(p11Key.length() + 7) >> 3];
285 }
286 if (type == T_UPDATE) {
287 token.p11.C_VerifyFinal(session.id(), signature);
288 } else {
289 byte[] digest;
290 if (type == T_DIGEST) {
291 digest = md.digest();
292 } else { // T_RAW
293 digest = buffer;
294 }
295 token.p11.C_Verify(session.id(), digest, signature);
296 }
297 } catch (PKCS11Exception e) {
298 // will fail since the signature is incorrect
299 // XXX check error code
300 }
301 }
302 }
303
304 // assumes current state is initialized == false
305 private void initialize() {
306 try {
307 if (session == null) {
308 session = token.getOpSession();
309 }
310 if (mode == M_SIGN) {
311 token.p11.C_SignInit(session.id(),
312 new CK_MECHANISM(mechanism), p11Key.keyID);
313 } else {
314 token.p11.C_VerifyInit(session.id(),
315 new CK_MECHANISM(mechanism), p11Key.keyID);
316 }
317 initialized = true;
318 } catch (PKCS11Exception e) {
319 throw new ProviderException("Initialization failed", e);
320 }
321 if (bytesProcessed != 0) {
322 bytesProcessed = 0;
323 if (md != null) {
324 md.reset();
325 }
326 }
327 }
328
329 private void checkRSAKeyLength(int len) throws InvalidKeyException {
330 RSAPadding padding;
331 try {
332 padding = RSAPadding.getInstance
333 (RSAPadding.PAD_BLOCKTYPE_1, (len + 7) >> 3);
334 } catch (InvalidAlgorithmParameterException iape) {
335 throw new InvalidKeyException(iape.getMessage());
336 }
337 int maxDataSize = padding.getMaxDataSize();
338 int encodedLength;
339 if (algorithm.equals("MD5withRSA") ||
340 algorithm.equals("MD2withRSA")) {
341 encodedLength = 34;
342 } else if (algorithm.equals("SHA1withRSA")) {
343 encodedLength = 35;
344 } else if (algorithm.equals("SHA224withRSA")) {
345 encodedLength = 47;
346 } else if (algorithm.equals("SHA256withRSA")) {
347 encodedLength = 51;
348 } else if (algorithm.equals("SHA384withRSA")) {
349 encodedLength = 67;
350 } else if (algorithm.equals("SHA512withRSA")) {
351 encodedLength = 83;
352 } else {
353 throw new ProviderException("Unknown signature algo: " + algorithm);
354 }
355 if (encodedLength > maxDataSize) {
356 throw new InvalidKeyException
357 ("Key is too short for this signature algorithm");
358 }
359 }
360
361 // see JCA spec
362 protected void engineInitVerify(PublicKey publicKey)
363 throws InvalidKeyException {
364 if (publicKey == null) {
365 throw new InvalidKeyException("Key must not be null");
366 }
367 // Need to check RSA key length whenever a new key is set
368 if (keyAlgorithm.equals("RSA") && publicKey != p11Key) {
369 int keyLen;
370 if (publicKey instanceof P11Key) {
371 keyLen = ((P11Key) publicKey).length();
372 } else {
373 keyLen = ((RSAKey) publicKey).getModulus().bitLength();
374 }
375 checkRSAKeyLength(keyLen);
376 }
377 cancelOperation();
378 mode = M_VERIFY;
379 p11Key = P11KeyFactory.convertKey(token, publicKey, keyAlgorithm);
380 initialize();
381 }
382
383 // see JCA spec
384 protected void engineInitSign(PrivateKey privateKey)
385 throws InvalidKeyException {
386 if (privateKey == null) {
387 throw new InvalidKeyException("Key must not be null");
388 }
389 // Need to check RSA key length whenever a new key is set
390 if (keyAlgorithm.equals("RSA") && privateKey != p11Key) {
391 int keyLen;
392 if (privateKey instanceof P11Key) {
393 keyLen = ((P11Key) privateKey).keyLength;
394 } else {
395 keyLen = ((RSAKey) privateKey).getModulus().bitLength();
396 }
397 checkRSAKeyLength(keyLen);
398 }
399 cancelOperation();
400 mode = M_SIGN;
401 p11Key = P11KeyFactory.convertKey(token, privateKey, keyAlgorithm);
402 initialize();
403 }
404
405 // see JCA spec
406 protected void engineUpdate(byte b) throws SignatureException {
407 ensureInitialized();
408 switch (type) {
409 case T_UPDATE:
410 buffer[0] = (byte)b;
411 engineUpdate(buffer, 0, 1);
412 break;
413 case T_DIGEST:
414 md.update(b);
415 bytesProcessed++;
416 break;
417 case T_RAW:
418 if (bytesProcessed >= buffer.length) {
419 bytesProcessed = buffer.length + 1;
420 return;
421 }
422 buffer[bytesProcessed++] = b;
423 break;
424 default:
425 throw new ProviderException("Internal error");
426 }
427 }
428
429 // see JCA spec
430 protected void engineUpdate(byte[] b, int ofs, int len)
431 throws SignatureException {
432 ensureInitialized();
433 if (len == 0) {
434 return;
435 }
436 switch (type) {
437 case T_UPDATE:
438 try {
439 if (mode == M_SIGN) {
440 token.p11.C_SignUpdate(session.id(), 0, b, ofs, len);
441 } else {
442 token.p11.C_VerifyUpdate(session.id(), 0, b, ofs, len);
443 }
444 bytesProcessed += len;
445 } catch (PKCS11Exception e) {
446 throw new ProviderException(e);
447 }
448 break;
449 case T_DIGEST:
450 md.update(b, ofs, len);
451 bytesProcessed += len;
452 break;
453 case T_RAW:
454 if (bytesProcessed + len > buffer.length) {
455 bytesProcessed = buffer.length + 1;
456 return;
457 }
458 System.arraycopy(b, ofs, buffer, bytesProcessed, len);
459 bytesProcessed += len;
460 break;
461 default:
462 throw new ProviderException("Internal error");
463 }
464 }
465
466 // see JCA spec
467 protected void engineUpdate(ByteBuffer byteBuffer) {
468 ensureInitialized();
469 int len = byteBuffer.remaining();
470 if (len <= 0) {
471 return;
472 }
473 switch (type) {
474 case T_UPDATE:
475 if (byteBuffer instanceof DirectBuffer == false) {
476 // cannot do better than default impl
477 super.engineUpdate(byteBuffer);
478 return;
479 }
480 long addr = ((DirectBuffer)byteBuffer).address();
481 int ofs = byteBuffer.position();
482 try {
483 if (mode == M_SIGN) {
484 token.p11.C_SignUpdate
485 (session.id(), addr + ofs, null, 0, len);
486 } else {
487 token.p11.C_VerifyUpdate
488 (session.id(), addr + ofs, null, 0, len);
489 }
490 bytesProcessed += len;
491 byteBuffer.position(ofs + len);
492 } catch (PKCS11Exception e) {
493 throw new ProviderException("Update failed", e);
494 }
495 break;
496 case T_DIGEST:
497 md.update(byteBuffer);
498 bytesProcessed += len;
499 break;
500 case T_RAW:
501 if (bytesProcessed + len > buffer.length) {
502 bytesProcessed = buffer.length + 1;
503 return;
504 }
505 byteBuffer.get(buffer, bytesProcessed, len);
506 bytesProcessed += len;
507 break;
508 default:
509 throw new ProviderException("Internal error");
510 }
511 }
512
513 // see JCA spec
514 protected byte[] engineSign() throws SignatureException {
515 ensureInitialized();
516 try {
517 byte[] signature;
518 if (type == T_UPDATE) {
519 int len = keyAlgorithm.equals("DSA") ? 40 : 0;
520 signature = token.p11.C_SignFinal(session.id(), len);
521 } else {
522 byte[] digest;
523 if (type == T_DIGEST) {
524 digest = md.digest();
525 } else { // T_RAW
526 if (mechanism == CKM_DSA) {
527 if (bytesProcessed != buffer.length) {
528 throw new SignatureException
529 ("Data for RawDSA must be exactly 20 bytes long");
530 }
531 digest = buffer;
532 } else { // CKM_ECDSA
533 if (bytesProcessed > buffer.length) {
534 throw new SignatureException("Data for NONEwithECDSA"
535 + " must be at most " + RAW_ECDSA_MAX + " bytes long");
536 }
537 digest = new byte[bytesProcessed];
538 System.arraycopy(buffer, 0, digest, 0, bytesProcessed);
539 }
540 }
541 if (keyAlgorithm.equals("RSA") == false) {
542 // DSA and ECDSA
543 signature = token.p11.C_Sign(session.id(), digest);
544 } else { // RSA
545 byte[] data = encodeSignature(digest);
546 if (mechanism == CKM_RSA_X_509) {
547 data = pkcs1Pad(data);
548 }
549 signature = token.p11.C_Sign(session.id(), data);
550 }
551 }
552 if (keyAlgorithm.equals("RSA") == false) {
553 return dsaToASN1(signature);
554 } else {
555 return signature;
556 }
557 } catch (PKCS11Exception e) {
558 throw new ProviderException(e);
559 } finally {
560 initialized = false;
561 session = token.releaseSession(session);
562 }
563 }
564
565 // see JCA spec
566 protected boolean engineVerify(byte[] signature) throws SignatureException {
567 ensureInitialized();
568 try {
569 if (keyAlgorithm.equals("DSA")) {
570 signature = asn1ToDSA(signature);
571 } else if (keyAlgorithm.equals("EC")) {
572 signature = asn1ToECDSA(signature);
573 }
574 if (type == T_UPDATE) {
575 token.p11.C_VerifyFinal(session.id(), signature);
576 } else {
577 byte[] digest;
578 if (type == T_DIGEST) {
579 digest = md.digest();
580 } else { // T_RAW
581 if (mechanism == CKM_DSA) {
582 if (bytesProcessed != buffer.length) {
583 throw new SignatureException
584 ("Data for RawDSA must be exactly 20 bytes long");
585 }
586 digest = buffer;
587 } else {
588 if (bytesProcessed > buffer.length) {
589 throw new SignatureException("Data for NONEwithECDSA"
590 + " must be at most " + RAW_ECDSA_MAX + " bytes long");
591 }
592 digest = new byte[bytesProcessed];
593 System.arraycopy(buffer, 0, digest, 0, bytesProcessed);
594 }
595 }
596 if (keyAlgorithm.equals("RSA") == false) {
597 // DSA and ECDSA
598 token.p11.C_Verify(session.id(), digest, signature);
599 } else { // RSA
600 byte[] data = encodeSignature(digest);
601 if (mechanism == CKM_RSA_X_509) {
602 data = pkcs1Pad(data);
603 }
604 token.p11.C_Verify(session.id(), data, signature);
605 }
606 }
607 return true;
608 } catch (PKCS11Exception e) {
609 long errorCode = e.getErrorCode();
610 if (errorCode == CKR_SIGNATURE_INVALID) {
611 return false;
612 }
613 if (errorCode == CKR_SIGNATURE_LEN_RANGE) {
614 // return false rather than throwing an exception
615 return false;
616 }
617 // ECF bug?
618 if (errorCode == CKR_DATA_LEN_RANGE) {
619 return false;
620 }
621 throw new ProviderException(e);
622 } finally {
623 // XXX we should not release the session if we abort above
624 // before calling C_Verify
625 initialized = false;
626 session = token.releaseSession(session);
627 }
628 }
629
630 private byte[] pkcs1Pad(byte[] data) {
631 try {
632 int len = (p11Key.length() + 7) >> 3;
633 RSAPadding padding = RSAPadding.getInstance
634 (RSAPadding.PAD_BLOCKTYPE_1, len);
635 byte[] padded = padding.pad(data);
636 return padded;
637 } catch (GeneralSecurityException e) {
638 throw new ProviderException(e);
639 }
640 }
641
642 private byte[] encodeSignature(byte[] digest) throws SignatureException {
643 try {
644 return RSASignature.encodeSignature(digestOID, digest);
645 } catch (IOException e) {
646 throw new SignatureException("Invalid encoding", e);
647 }
648 }
649
650 // private static byte[] decodeSignature(byte[] signature) throws IOException {
651 // return RSASignature.decodeSignature(digestOID, signature);
652 // }
653
654 // For DSA and ECDSA signatures, PKCS#11 represents them as a simple
655 // byte array that contains the concatenation of r and s.
656 // For DSA, r and s are always exactly 20 bytes long.
657 // For ECDSA, r and s are of variable length, but we know that each
658 // occupies half of the array.
659 private static byte[] dsaToASN1(byte[] signature) {
660 int n = signature.length >> 1;
661 BigInteger r = new BigInteger(1, P11Util.subarray(signature, 0, n));
662 BigInteger s = new BigInteger(1, P11Util.subarray(signature, n, n));
663 try {
664 DerOutputStream outseq = new DerOutputStream(100);
665 outseq.putInteger(r);
666 outseq.putInteger(s);
667 DerValue result = new DerValue(DerValue.tag_Sequence,
668 outseq.toByteArray());
669 return result.toByteArray();
670 } catch (java.io.IOException e) {
671 throw new RuntimeException("Internal error", e);
672 }
673 }
674
675 private static byte[] asn1ToDSA(byte[] signature) throws SignatureException {
676 try {
677 DerInputStream in = new DerInputStream(signature);
678 DerValue[] values = in.getSequence(2);
679 BigInteger r = values[0].getPositiveBigInteger();
680 BigInteger s = values[1].getPositiveBigInteger();
681 byte[] br = toByteArray(r, 20);
682 byte[] bs = toByteArray(s, 20);
683 if ((br == null) || (bs == null)) {
684 throw new SignatureException("Out of range value for R or S");
685 }
686 return P11Util.concat(br, bs);
687 } catch (SignatureException e) {
688 throw e;
689 } catch (Exception e) {
690 throw new SignatureException("invalid encoding for signature", e);
691 }
692 }
693
694 private byte[] asn1ToECDSA(byte[] signature) throws SignatureException {
695 try {
696 DerInputStream in = new DerInputStream(signature);
697 DerValue[] values = in.getSequence(2);
698 BigInteger r = values[0].getPositiveBigInteger();
699 BigInteger s = values[1].getPositiveBigInteger();
700 // trim leading zeroes
701 byte[] br = KeyUtil.trimZeroes(r.toByteArray());
702 byte[] bs = KeyUtil.trimZeroes(s.toByteArray());
703 int k = Math.max(br.length, bs.length);
704 // r and s each occupy half the array
705 byte[] res = new byte[k << 1];
706 System.arraycopy(br, 0, res, k - br.length, br.length);
707 System.arraycopy(bs, 0, res, res.length - bs.length, bs.length);
708 return res;
709 } catch (Exception e) {
710 throw new SignatureException("invalid encoding for signature", e);
711 }
712 }
713
714 private static byte[] toByteArray(BigInteger bi, int len) {
715 byte[] b = bi.toByteArray();
716 int n = b.length;
717 if (n == len) {
718 return b;
719 }
720 if ((n == len + 1) && (b[0] == 0)) {
721 byte[] t = new byte[len];
722 System.arraycopy(b, 1, t, 0, len);
723 return t;
724 }
725 if (n > len) {
726 return null;
727 }
728 // must be smaller
729 byte[] t = new byte[len];
730 System.arraycopy(b, 0, t, (len - n), n);
731 return t;
732 }
733
734 // see JCA spec
735 protected void engineSetParameter(String param, Object value)
736 throws InvalidParameterException {
737 throw new UnsupportedOperationException("setParameter() not supported");
738 }
739
740 // see JCA spec
741 protected Object engineGetParameter(String param)
742 throws InvalidParameterException {
743 throw new UnsupportedOperationException("getParameter() not supported");
744 }
745 }