1 /*
   2  * Copyright (c) 2003, 2015, 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.security.*;
  29 import java.security.spec.AlgorithmParameterSpec;
  30 import java.security.spec.*;
  31 
  32 import java.util.Locale;
  33 
  34 import javax.crypto.*;
  35 import javax.crypto.spec.*;
  36 
  37 import static sun.security.pkcs11.TemplateManager.*;
  38 import sun.security.pkcs11.wrapper.*;
  39 import static sun.security.pkcs11.wrapper.PKCS11Constants.*;
  40 import sun.security.internal.spec.TlsRsaPremasterSecretParameterSpec;
  41 import sun.security.util.KeyUtil;
  42 
  43 /**
  44  * RSA Cipher implementation class. We currently only support
  45  * PKCS#1 v1.5 padding on top of CKM_RSA_PKCS.
  46  *
  47  * @author  Andreas Sterbenz
  48  * @since   1.5
  49  */
  50 final class P11RSACipher extends CipherSpi {
  51 
  52     // minimum length of PKCS#1 v1.5 padding
  53     private final static int PKCS1_MIN_PADDING_LENGTH = 11;
  54 
  55     // constant byte[] of length 0
  56     private final static byte[] B0 = new byte[0];
  57 
  58     // mode constant for public key encryption
  59     private final static int MODE_ENCRYPT = 1;
  60     // mode constant for private key decryption
  61     private final static int MODE_DECRYPT = 2;
  62     // mode constant for private key encryption (signing)
  63     private final static int MODE_SIGN    = 3;
  64     // mode constant for public key decryption (verifying)
  65     private final static int MODE_VERIFY  = 4;
  66 
  67     // padding type constant for NoPadding
  68     private final static int PAD_NONE = 1;
  69     // padding type constant for PKCS1Padding
  70     private final static int PAD_PKCS1 = 2;
  71 
  72     // token instance
  73     private final Token token;
  74 
  75     // algorithm name (always "RSA")
  76     private final String algorithm;
  77 
  78     // mechanism id
  79     private final long mechanism;
  80 
  81     // associated session, if any
  82     private Session session;
  83 
  84     // mode, one of MODE_* above
  85     private int mode;
  86 
  87     // padding, one of PAD_* above
  88     private int padType;
  89 
  90     private byte[] buffer;
  91     private int bufOfs;
  92 
  93     // key, if init() was called
  94     private P11Key p11Key;
  95 
  96     // flag indicating whether an operation is initialized
  97     private boolean initialized;
  98 
  99     // maximum input data size allowed
 100     // for decryption, this is the length of the key
 101     // for encryption, length of the key minus minimum padding length
 102     private int maxInputSize;
 103 
 104     // maximum output size. this is the length of the key
 105     private int outputSize;
 106 
 107     // cipher parameter for TLS RSA premaster secret
 108     private AlgorithmParameterSpec spec = null;
 109 
 110     // the source of randomness
 111     private SecureRandom random;
 112 
 113     P11RSACipher(Token token, String algorithm, long mechanism)
 114             throws PKCS11Exception {
 115         super();
 116         this.token = token;
 117         this.algorithm = "RSA";
 118         this.mechanism = mechanism;
 119     }
 120 
 121     // modes do not make sense for RSA, but allow ECB
 122     // see JCE spec
 123     protected void engineSetMode(String mode) throws NoSuchAlgorithmException {
 124         if (mode.equalsIgnoreCase("ECB") == false) {
 125             throw new NoSuchAlgorithmException("Unsupported mode " + mode);
 126         }
 127     }
 128 
 129     protected void engineSetPadding(String padding)
 130             throws NoSuchPaddingException {
 131         String lowerPadding = padding.toLowerCase(Locale.ENGLISH);
 132         if (lowerPadding.equals("pkcs1padding")) {
 133             padType = PAD_PKCS1;
 134         } else if (lowerPadding.equals("nopadding")) {
 135             padType = PAD_NONE;
 136         } else {
 137             throw new NoSuchPaddingException("Unsupported padding " + padding);
 138         }
 139     }
 140 
 141     // return 0 as block size, we are not a block cipher
 142     // see JCE spec
 143     protected int engineGetBlockSize() {
 144         return 0;
 145     }
 146 
 147     // return the output size
 148     // see JCE spec
 149     protected int engineGetOutputSize(int inputLen) {
 150         return outputSize;
 151     }
 152 
 153     // no IV, return null
 154     // see JCE spec
 155     protected byte[] engineGetIV() {
 156         return null;
 157     }
 158 
 159     // no parameters, return null
 160     // see JCE spec
 161     protected AlgorithmParameters engineGetParameters() {
 162         return null;
 163     }
 164 
 165     // see JCE spec
 166     protected void engineInit(int opmode, Key key, SecureRandom random)
 167             throws InvalidKeyException {
 168         implInit(opmode, key);
 169     }
 170 
 171     // see JCE spec
 172     @SuppressWarnings("deprecation")
 173     protected void engineInit(int opmode, Key key,
 174             AlgorithmParameterSpec params, SecureRandom random)
 175             throws InvalidKeyException, InvalidAlgorithmParameterException {
 176         if (params != null) {
 177             if (!(params instanceof TlsRsaPremasterSecretParameterSpec)) {
 178                 throw new InvalidAlgorithmParameterException(
 179                         "Parameters not supported");
 180             }
 181             spec = params;
 182             this.random = random;   // for TLS RSA premaster secret
 183         }
 184         implInit(opmode, key);
 185     }
 186 
 187     // see JCE spec
 188     protected void engineInit(int opmode, Key key, AlgorithmParameters params,
 189             SecureRandom random)
 190             throws InvalidKeyException, InvalidAlgorithmParameterException {
 191         if (params != null) {
 192             throw new InvalidAlgorithmParameterException(
 193                         "Parameters not supported");
 194         }
 195         implInit(opmode, key);
 196     }
 197 
 198     private void implInit(int opmode, Key key) throws InvalidKeyException {
 199         cancelOperation();
 200         p11Key = P11KeyFactory.convertKey(token, key, algorithm);
 201         boolean encrypt;
 202         if (opmode == Cipher.ENCRYPT_MODE) {
 203             encrypt = true;
 204         } else if (opmode == Cipher.DECRYPT_MODE) {
 205             encrypt = false;
 206         } else if (opmode == Cipher.WRAP_MODE) {
 207             if (p11Key.isPublic() == false) {
 208                 throw new InvalidKeyException
 209                                 ("Wrap has to be used with public keys");
 210             }
 211             // No further setup needed for C_Wrap(). We'll initialize later if
 212             // we can't use C_Wrap().
 213             return;
 214         } else if (opmode == Cipher.UNWRAP_MODE) {
 215             if (p11Key.isPrivate() == false) {
 216                 throw new InvalidKeyException
 217                                 ("Unwrap has to be used with private keys");
 218             }
 219             // No further setup needed for C_Unwrap(). We'll initialize later
 220             // if we can't use C_Unwrap().
 221             return;
 222         } else {
 223             throw new InvalidKeyException("Unsupported mode: " + opmode);
 224         }
 225         if (p11Key.isPublic()) {
 226             mode = encrypt ? MODE_ENCRYPT : MODE_VERIFY;
 227         } else if (p11Key.isPrivate()) {
 228             mode = encrypt ? MODE_SIGN : MODE_DECRYPT;
 229         } else {
 230             throw new InvalidKeyException("Unknown key type: " + p11Key);
 231         }
 232         int n = (p11Key.length() + 7) >> 3;
 233         outputSize = n;
 234         buffer = new byte[n];
 235         maxInputSize = ((padType == PAD_PKCS1 && encrypt) ?
 236                             (n - PKCS1_MIN_PADDING_LENGTH) : n);
 237         try {
 238             initialize();
 239         } catch (PKCS11Exception e) {
 240             throw new InvalidKeyException("init() failed", e);
 241         }
 242     }
 243 
 244     private void cancelOperation() {
 245         token.ensureValid();
 246         if (initialized == false) {
 247             return;
 248         }
 249         initialized = false;
 250         if ((session == null) || (token.explicitCancel == false)) {
 251             return;
 252         }
 253         if (session.hasObjects() == false) {
 254             session = token.killSession(session);
 255             return;
 256         }
 257         try {
 258             PKCS11 p11 = token.p11;
 259             int inLen = maxInputSize;
 260             int outLen = buffer.length;
 261             switch (mode) {
 262             case MODE_ENCRYPT:
 263                 p11.C_Encrypt
 264                         (session.id(), buffer, 0, inLen, buffer, 0, outLen);
 265                 break;
 266             case MODE_DECRYPT:
 267                 p11.C_Decrypt
 268                         (session.id(), buffer, 0, inLen, buffer, 0, outLen);
 269                 break;
 270             case MODE_SIGN:
 271                 byte[] tmpBuffer = new byte[maxInputSize];
 272                 p11.C_Sign
 273                         (session.id(), tmpBuffer);
 274                 break;
 275             case MODE_VERIFY:
 276                 p11.C_VerifyRecover
 277                         (session.id(), buffer, 0, inLen, buffer, 0, outLen);
 278                 break;
 279             default:
 280                 throw new ProviderException("internal error");
 281             }
 282         } catch (PKCS11Exception e) {
 283             // XXX ensure this always works, ignore error
 284         }
 285     }
 286 
 287     private void ensureInitialized() throws PKCS11Exception {
 288         token.ensureValid();
 289         if (initialized == false) {
 290             initialize();
 291         }
 292     }
 293 
 294     private void initialize() throws PKCS11Exception {
 295         if (session == null) {
 296             session = token.getOpSession();
 297         }
 298         PKCS11 p11 = token.p11;
 299         CK_MECHANISM ckMechanism = new CK_MECHANISM(mechanism);
 300         switch (mode) {
 301         case MODE_ENCRYPT:
 302             p11.C_EncryptInit(session.id(), ckMechanism, p11Key.keyID);
 303             break;
 304         case MODE_DECRYPT:
 305             p11.C_DecryptInit(session.id(), ckMechanism, p11Key.keyID);
 306             break;
 307         case MODE_SIGN:
 308             p11.C_SignInit(session.id(), ckMechanism, p11Key.keyID);
 309             break;
 310         case MODE_VERIFY:
 311             p11.C_VerifyRecoverInit(session.id(), ckMechanism, p11Key.keyID);
 312             break;
 313         default:
 314             throw new AssertionError("internal error");
 315         }
 316         bufOfs = 0;
 317         initialized = true;
 318     }
 319 
 320     private void implUpdate(byte[] in, int inOfs, int inLen) {
 321         try {
 322             ensureInitialized();
 323         } catch (PKCS11Exception e) {
 324             throw new ProviderException("update() failed", e);
 325         }
 326         if ((inLen == 0) || (in == null)) {
 327             return;
 328         }
 329         if (bufOfs + inLen > maxInputSize) {
 330             bufOfs = maxInputSize + 1;
 331             return;
 332         }
 333         System.arraycopy(in, inOfs, buffer, bufOfs, inLen);
 334         bufOfs += inLen;
 335     }
 336 
 337     private int implDoFinal(byte[] out, int outOfs, int outLen)
 338             throws BadPaddingException, IllegalBlockSizeException {
 339         if (bufOfs > maxInputSize) {
 340             throw new IllegalBlockSizeException("Data must not be longer "
 341                 + "than " + maxInputSize + " bytes");
 342         }
 343         try {
 344             ensureInitialized();
 345             PKCS11 p11 = token.p11;
 346             int n;
 347             switch (mode) {
 348             case MODE_ENCRYPT:
 349                 n = p11.C_Encrypt
 350                         (session.id(), buffer, 0, bufOfs, out, outOfs, outLen);
 351                 break;
 352             case MODE_DECRYPT:
 353                 n = p11.C_Decrypt
 354                         (session.id(), buffer, 0, bufOfs, out, outOfs, outLen);
 355                 break;
 356             case MODE_SIGN:
 357                 byte[] tmpBuffer = new byte[bufOfs];
 358                 System.arraycopy(buffer, 0, tmpBuffer, 0, bufOfs);
 359                 tmpBuffer = p11.C_Sign(session.id(), tmpBuffer);
 360                 if (tmpBuffer.length > outLen) {
 361                     throw new BadPaddingException(
 362                         "Output buffer (" + outLen + ") is too small to " +
 363                         "hold the produced data (" + tmpBuffer.length + ")");
 364                 }
 365                 System.arraycopy(tmpBuffer, 0, out, outOfs, tmpBuffer.length);
 366                 n = tmpBuffer.length;
 367                 break;
 368             case MODE_VERIFY:
 369                 n = p11.C_VerifyRecover
 370                         (session.id(), buffer, 0, bufOfs, out, outOfs, outLen);
 371                 break;
 372             default:
 373                 throw new ProviderException("internal error");
 374             }
 375             return n;
 376         } catch (PKCS11Exception e) {
 377             throw (BadPaddingException)new BadPaddingException
 378                 ("doFinal() failed").initCause(e);
 379         } finally {
 380             initialized = false;
 381             session = token.releaseSession(session);
 382         }
 383     }
 384 
 385     // see JCE spec
 386     protected byte[] engineUpdate(byte[] in, int inOfs, int inLen) {
 387         implUpdate(in, inOfs, inLen);
 388         return B0;
 389     }
 390 
 391     // see JCE spec
 392     protected int engineUpdate(byte[] in, int inOfs, int inLen,
 393             byte[] out, int outOfs) throws ShortBufferException {
 394         implUpdate(in, inOfs, inLen);
 395         return 0;
 396     }
 397 
 398     // see JCE spec
 399     protected byte[] engineDoFinal(byte[] in, int inOfs, int inLen)
 400             throws IllegalBlockSizeException, BadPaddingException {
 401         implUpdate(in, inOfs, inLen);
 402         int n = implDoFinal(buffer, 0, buffer.length);
 403         byte[] out = new byte[n];
 404         System.arraycopy(buffer, 0, out, 0, n);
 405         return out;
 406     }
 407 
 408     // see JCE spec
 409     protected int engineDoFinal(byte[] in, int inOfs, int inLen,
 410             byte[] out, int outOfs) throws ShortBufferException,
 411             IllegalBlockSizeException, BadPaddingException {
 412         implUpdate(in, inOfs, inLen);
 413         return implDoFinal(out, outOfs, out.length - outOfs);
 414     }
 415 
 416     private byte[] doFinal() throws BadPaddingException,
 417             IllegalBlockSizeException {
 418         byte[] t = new byte[2048];
 419         int n = implDoFinal(t, 0, t.length);
 420         byte[] out = new byte[n];
 421         System.arraycopy(t, 0, out, 0, n);
 422         return out;
 423     }
 424 
 425     // see JCE spec
 426     protected byte[] engineWrap(Key key) throws InvalidKeyException,
 427             IllegalBlockSizeException {
 428         String keyAlg = key.getAlgorithm();
 429         P11Key sKey = null;
 430         try {
 431             // The conversion may fail, e.g. trying to wrap an AES key on
 432             // a token that does not support AES, or when the key size is
 433             // not within the range supported by the token.
 434             sKey = P11SecretKeyFactory.convertKey(token, key, keyAlg);
 435         } catch (InvalidKeyException ike) {
 436             byte[] toBeWrappedKey = key.getEncoded();
 437             if (toBeWrappedKey == null) {
 438                 throw new InvalidKeyException
 439                         ("wrap() failed, no encoding available", ike);
 440             }
 441             // Directly encrypt the key encoding when key conversion failed
 442             implInit(Cipher.ENCRYPT_MODE, p11Key);
 443             implUpdate(toBeWrappedKey, 0, toBeWrappedKey.length);
 444             try {
 445                 return doFinal();
 446             } catch (BadPaddingException bpe) {
 447                 // should not occur
 448                 throw new InvalidKeyException("wrap() failed", bpe);
 449             } finally {
 450                 // Restore original mode
 451                 implInit(Cipher.WRAP_MODE, p11Key);
 452             }
 453         }
 454         Session s = null;
 455         try {
 456             s = token.getOpSession();
 457             return token.p11.C_WrapKey(s.id(), new CK_MECHANISM(mechanism),
 458                 p11Key.keyID, sKey.keyID);
 459         } catch (PKCS11Exception e) {
 460             throw new InvalidKeyException("wrap() failed", e);
 461         } finally {
 462             token.releaseSession(s);
 463         }
 464     }
 465 
 466     // see JCE spec
 467     @SuppressWarnings("deprecation")
 468     protected Key engineUnwrap(byte[] wrappedKey, String algorithm,
 469             int type) throws InvalidKeyException, NoSuchAlgorithmException {
 470 
 471         boolean isTlsRsaPremasterSecret =
 472                 algorithm.equals("TlsRsaPremasterSecret");
 473         Exception failover = null;
 474 
 475         // Should C_Unwrap be preferred for non-TLS RSA premaster secret?
 476         if (token.supportsRawSecretKeyImport()) {
 477             // XXX implement unwrap using C_Unwrap() for all keys
 478             implInit(Cipher.DECRYPT_MODE, p11Key);
 479             try {
 480                 if (wrappedKey.length > maxInputSize) {
 481                     throw new InvalidKeyException("Key is too long for unwrapping");
 482                 }
 483 
 484                 byte[] encoded = null;
 485                 implUpdate(wrappedKey, 0, wrappedKey.length);
 486                 try {
 487                     encoded = doFinal();
 488                 } catch (BadPaddingException e) {
 489                     if (isTlsRsaPremasterSecret) {
 490                         failover = e;
 491                     } else {
 492                         throw new InvalidKeyException("Unwrapping failed", e);
 493                     }
 494                 } catch (IllegalBlockSizeException e) {
 495                     // should not occur, handled with length check above
 496                     throw new InvalidKeyException("Unwrapping failed", e);
 497                 }
 498 
 499                 if (isTlsRsaPremasterSecret) {
 500                     if (!(spec instanceof TlsRsaPremasterSecretParameterSpec)) {
 501                         throw new IllegalStateException(
 502                                 "No TlsRsaPremasterSecretParameterSpec specified");
 503                     }
 504 
 505                     // polish the TLS premaster secret
 506                     TlsRsaPremasterSecretParameterSpec psps =
 507                             (TlsRsaPremasterSecretParameterSpec)spec;
 508                     encoded = KeyUtil.checkTlsPreMasterSecretKey(
 509                             psps.getClientVersion(), psps.getServerVersion(),
 510                             random, encoded, (failover != null));
 511                 }
 512 
 513                 return ConstructKeys.constructKey(encoded, algorithm, type);
 514             } finally {
 515                 // Restore original mode
 516                 implInit(Cipher.UNWRAP_MODE, p11Key);
 517             }
 518         } else {
 519             Session s = null;
 520             SecretKey secretKey = null;
 521             try {
 522                 try {
 523                     s = token.getObjSession();
 524                     long keyType = CKK_GENERIC_SECRET;
 525                     CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
 526                             new CK_ATTRIBUTE(CKA_CLASS, CKO_SECRET_KEY),
 527                             new CK_ATTRIBUTE(CKA_KEY_TYPE, keyType),
 528                         };
 529                     attributes = token.getAttributes(
 530                             O_IMPORT, CKO_SECRET_KEY, keyType, attributes);
 531                     long keyID = token.p11.C_UnwrapKey(s.id(),
 532                             new CK_MECHANISM(mechanism), p11Key.keyID,
 533                             wrappedKey, attributes);
 534                     secretKey = P11Key.secretKey(s, keyID,
 535                             algorithm, 48 << 3, attributes);
 536                 } catch (PKCS11Exception e) {
 537                     if (isTlsRsaPremasterSecret) {
 538                         failover = e;
 539                     } else {
 540                         throw new InvalidKeyException("unwrap() failed", e);
 541                     }
 542                 }
 543 
 544                 if (isTlsRsaPremasterSecret) {
 545                     TlsRsaPremasterSecretParameterSpec psps =
 546                             (TlsRsaPremasterSecretParameterSpec)spec;
 547 
 548                     // Please use the tricky failover as the parameter so that
 549                     // smart compiler won't dispose the unused variable.
 550                     secretKey = polishPreMasterSecretKey(token, s,
 551                             failover, secretKey,
 552                             psps.getClientVersion(), psps.getServerVersion());
 553                 }
 554 
 555                 return secretKey;
 556             } finally {
 557                 token.releaseSession(s);
 558             }
 559         }
 560     }
 561 
 562     // see JCE spec
 563     protected int engineGetKeySize(Key key) throws InvalidKeyException {
 564         int n = P11KeyFactory.convertKey(token, key, algorithm).length();
 565         return n;
 566     }
 567 
 568     private static SecretKey polishPreMasterSecretKey(
 569             Token token, Session session,
 570             Exception failover, SecretKey unwrappedKey,
 571             int clientVersion, int serverVersion) {
 572 
 573         SecretKey newKey;
 574         CK_VERSION version = new CK_VERSION(
 575                 (clientVersion >>> 8) & 0xFF, clientVersion & 0xFF);
 576         try {
 577             CK_ATTRIBUTE[] attributes = token.getAttributes(
 578                     O_GENERATE, CKO_SECRET_KEY,
 579                     CKK_GENERIC_SECRET, new CK_ATTRIBUTE[0]);
 580             long keyID = token.p11.C_GenerateKey(session.id(),
 581                     new CK_MECHANISM(CKM_SSL3_PRE_MASTER_KEY_GEN, version),
 582                     attributes);
 583             newKey = P11Key.secretKey(session,
 584                     keyID, "TlsRsaPremasterSecret", 48 << 3, attributes);
 585         } catch (PKCS11Exception e) {
 586             throw new ProviderException(
 587                     "Could not generate premaster secret", e);
 588         }
 589 
 590         return (failover == null) ? unwrappedKey : newKey;
 591     }
 592 
 593 }
 594 
 595 final class ConstructKeys {
 596     /**
 597      * Construct a public key from its encoding.
 598      *
 599      * @param encodedKey the encoding of a public key.
 600      *
 601      * @param encodedKeyAlgorithm the algorithm the encodedKey is for.
 602      *
 603      * @return a public key constructed from the encodedKey.
 604      */
 605     private static final PublicKey constructPublicKey(byte[] encodedKey,
 606             String encodedKeyAlgorithm)
 607             throws InvalidKeyException, NoSuchAlgorithmException {
 608         try {
 609             KeyFactory keyFactory =
 610                 KeyFactory.getInstance(encodedKeyAlgorithm);
 611             X509EncodedKeySpec keySpec = new X509EncodedKeySpec(encodedKey);
 612             return keyFactory.generatePublic(keySpec);
 613         } catch (NoSuchAlgorithmException nsae) {
 614             throw new NoSuchAlgorithmException("No installed providers " +
 615                                                "can create keys for the " +
 616                                                encodedKeyAlgorithm +
 617                                                "algorithm", nsae);
 618         } catch (InvalidKeySpecException ike) {
 619             throw new InvalidKeyException("Cannot construct public key", ike);
 620         }
 621     }
 622 
 623     /**
 624      * Construct a private key from its encoding.
 625      *
 626      * @param encodedKey the encoding of a private key.
 627      *
 628      * @param encodedKeyAlgorithm the algorithm the wrapped key is for.
 629      *
 630      * @return a private key constructed from the encodedKey.
 631      */
 632     private static final PrivateKey constructPrivateKey(byte[] encodedKey,
 633             String encodedKeyAlgorithm) throws InvalidKeyException,
 634             NoSuchAlgorithmException {
 635         try {
 636             KeyFactory keyFactory =
 637                 KeyFactory.getInstance(encodedKeyAlgorithm);
 638             PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encodedKey);
 639             return keyFactory.generatePrivate(keySpec);
 640         } catch (NoSuchAlgorithmException nsae) {
 641             throw new NoSuchAlgorithmException("No installed providers " +
 642                                                "can create keys for the " +
 643                                                encodedKeyAlgorithm +
 644                                                "algorithm", nsae);
 645         } catch (InvalidKeySpecException ike) {
 646             throw new InvalidKeyException("Cannot construct private key", ike);
 647         }
 648     }
 649 
 650     /**
 651      * Construct a secret key from its encoding.
 652      *
 653      * @param encodedKey the encoding of a secret key.
 654      *
 655      * @param encodedKeyAlgorithm the algorithm the secret key is for.
 656      *
 657      * @return a secret key constructed from the encodedKey.
 658      */
 659     private static final SecretKey constructSecretKey(byte[] encodedKey,
 660             String encodedKeyAlgorithm) {
 661         return new SecretKeySpec(encodedKey, encodedKeyAlgorithm);
 662     }
 663 
 664     static final Key constructKey(byte[] encoding, String keyAlgorithm,
 665             int keyType) throws InvalidKeyException, NoSuchAlgorithmException {
 666         switch (keyType) {
 667         case Cipher.SECRET_KEY:
 668             return constructSecretKey(encoding, keyAlgorithm);
 669         case Cipher.PRIVATE_KEY:
 670             return constructPrivateKey(encoding, keyAlgorithm);
 671         case Cipher.PUBLIC_KEY:
 672             return constructPublicKey(encoding, keyAlgorithm);
 673         default:
 674             throw new InvalidKeyException("Unknown keytype " + keyType);
 675         }
 676     }
 677 }