AlgorithmParameters implGetParameters() {
   AlgorithmParameters params = null;
   if (salt == null) {
     // Cipher is not initialized with parameters;
     // follow the recommendation in PKCS12 v1.0
     // section B.4 to generate salt and iCount.
     salt = new byte[DEFAULT_SALT_LENGTH];
     SunJCE.getRandom().nextBytes(salt);
     iCount = DEFAULT_COUNT;
   }
   PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, iCount);
   try {
     params = AlgorithmParameters.getInstance(pbeAlgo, "SunJCE");
   } catch (GeneralSecurityException gse) {
     // should never happen
     throw new RuntimeException("SunJCE provider is not configured properly");
   }
   try {
     params.init(pbeSpec);
   } catch (InvalidParameterSpecException ipse) {
     // should never happen
     throw new RuntimeException("PBEParameterSpec not supported");
   }
   return params;
 }
  void implInit(
      int opmode, Key key, AlgorithmParameterSpec params, SecureRandom random, CipherSpi cipherImpl)
      throws InvalidKeyException, InvalidAlgorithmParameterException {
    char[] passwdChars = null;
    salt = null;
    iCount = 0;
    if (key instanceof javax.crypto.interfaces.PBEKey) {
      javax.crypto.interfaces.PBEKey pbeKey = (javax.crypto.interfaces.PBEKey) key;
      passwdChars = pbeKey.getPassword();
      salt = pbeKey.getSalt(); // maybe null if unspecified
      iCount = pbeKey.getIterationCount(); // maybe 0 if unspecified
    } else if (key instanceof SecretKey) {
      byte[] passwdBytes = key.getEncoded();
      if ((passwdBytes == null) || !(key.getAlgorithm().regionMatches(true, 0, "PBE", 0, 3))) {
        throw new InvalidKeyException("Missing password");
      }
      passwdChars = new char[passwdBytes.length];
      for (int i = 0; i < passwdChars.length; i++) {
        passwdChars[i] = (char) (passwdBytes[i] & 0x7f);
      }
    } else {
      throw new InvalidKeyException("SecretKey of PBE type required");
    }

    if (((opmode == Cipher.DECRYPT_MODE) || (opmode == Cipher.UNWRAP_MODE))
        && ((params == null) && ((salt == null) || (iCount == 0)))) {
      throw new InvalidAlgorithmParameterException("Parameters missing");
    }

    if (params == null) {
      // generate default for salt and iteration count if necessary
      if (salt == null) {
        salt = new byte[DEFAULT_SALT_LENGTH];
        if (random != null) {
          random.nextBytes(salt);
        } else {
          SunJCE.getRandom().nextBytes(salt);
        }
      }
      if (iCount == 0) iCount = DEFAULT_COUNT;
    } else if (!(params instanceof PBEParameterSpec)) {
      throw new InvalidAlgorithmParameterException("PBEParameterSpec type required");
    } else {
      PBEParameterSpec pbeParams = (PBEParameterSpec) params;
      // make sure the parameter values are consistent
      if (salt != null) {
        if (!Arrays.equals(salt, pbeParams.getSalt())) {
          throw new InvalidAlgorithmParameterException(
              "Inconsistent value of salt between key and params");
        }
      } else {
        salt = pbeParams.getSalt();
      }
      if (iCount != 0) {
        if (iCount != pbeParams.getIterationCount()) {
          throw new InvalidAlgorithmParameterException(
              "Different iteration count between key and params");
        }
      } else {
        iCount = pbeParams.getIterationCount();
      }
    }
    // salt is recommended to be ideally as long as the output
    // of the hash function. However, it may be too strict to
    // force this; so instead, we'll just require the minimum
    // salt length to be 8-byte which is what PKCS#5 recommends
    // and openssl does.
    if (salt.length < 8) {
      throw new InvalidAlgorithmParameterException("Salt must be at least 8 bytes long");
    }
    if (iCount <= 0) {
      throw new InvalidAlgorithmParameterException("IterationCount must be a positive number");
    }
    byte[] derivedKey = derive(passwdChars, salt, iCount, keySize, CIPHER_KEY);
    SecretKey cipherKey = new SecretKeySpec(derivedKey, algo);

    if (cipherImpl != null && cipherImpl instanceof ARCFOURCipher) {
      ((ARCFOURCipher) cipherImpl).engineInit(opmode, cipherKey, random);

    } else {
      byte[] derivedIv = derive(passwdChars, salt, iCount, 8, CIPHER_IV);
      IvParameterSpec ivSpec = new IvParameterSpec(derivedIv, 0, 8);

      // initialize the underlying cipher
      cipher.init(opmode, cipherKey, ivSpec, random);
    }
  }