Java Code Examples for org.apache.hadoop.crypto.CryptoCodec#getInstance()

public static CryptoCodec getCryptoCodec(ConfigurationSource conf,
    FileEncryptionInfo feInfo) throws IOException {
  CipherSuite suite = feInfo.getCipherSuite();
  if (suite.equals(CipherSuite.UNKNOWN)) {
    throw new IOException("NameNode specified unknown CipherSuite with ID " +
            suite.getUnknownValue() + ", cannot instantiate CryptoCodec.");
  } else {
    Configuration hadoopConfig =
        LegacyHadoopConfigurationSource.asHadoopConfiguration(conf);
    CryptoCodec codec = CryptoCodec.getInstance(hadoopConfig, suite);
    if (codec == null) {
      throw new OMException("No configuration found for the cipher suite " +
              suite.getConfigSuffix() + " prefixed with " +
              "hadoop.security.crypto.codec.classes. Please see the" +
              " example configuration hadoop.security.crypto.codec.classes." +
              "EXAMPLE CIPHER SUITE at core-default.xml for details.",
              OMException.ResultCodes.UNKNOWN_CIPHER_SUITE);
    } else {
      return codec;
    }
  }
}
 

/**
 * Wraps a given FSDataOutputStream with a CryptoOutputStream. The size of the
 * data buffer required for the stream is specified by the
 * "mapreduce.job.encrypted-intermediate-data.buffer.kb" Job configuration
 * variable.
 * 
 * @param conf
 * @param out
 * @return FSDataOutputStream
 * @throws IOException
 */
public static FSDataOutputStream wrapIfNecessary(Configuration conf,
    FSDataOutputStream out) throws IOException {
  if (isEncryptedSpillEnabled(conf)) {
    out.write(ByteBuffer.allocate(8).putLong(out.getPos()).array());
    byte[] iv = createIV(conf);
    out.write(iv);
    if (LOG.isDebugEnabled()) {
      LOG.debug("IV written to Stream ["
          + Base64.encodeBase64URLSafeString(iv) + "]");
    }
    return new CryptoFSDataOutputStream(out, CryptoCodec.getInstance(conf),
        getBufferSize(conf), getEncryptionKey(), iv);
  } else {
    return out;
  }
}
 

/**
 * Wraps a given InputStream with a CryptoInputStream. The size of the data
 * buffer required for the stream is specified by the
 * "mapreduce.job.encrypted-intermediate-data.buffer.kb" Job configuration
 * variable.
 * 
 * If the value of 'length' is > -1, The InputStream is additionally
 * wrapped in a LimitInputStream. CryptoStreams are late buffering in nature.
 * This means they will always try to read ahead if they can. The
 * LimitInputStream will ensure that the CryptoStream does not read past the
 * provided length from the given Input Stream.
 * 
 * @param conf
 * @param in
 * @param length
 * @return InputStream
 * @throws IOException
 */
public static InputStream wrapIfNecessary(Configuration conf, InputStream in,
    long length) throws IOException {
  if (isEncryptedSpillEnabled(conf)) {
    int bufferSize = getBufferSize(conf);
    if (length > -1) {
      in = new LimitInputStream(in, length);
    }
    byte[] offsetArray = new byte[8];
    IOUtils.readFully(in, offsetArray, 0, 8);
    long offset = ByteBuffer.wrap(offsetArray).getLong();
    CryptoCodec cryptoCodec = CryptoCodec.getInstance(conf);
    byte[] iv = 
        new byte[cryptoCodec.getCipherSuite().getAlgorithmBlockSize()];
    IOUtils.readFully(in, iv, 0, 
        cryptoCodec.getCipherSuite().getAlgorithmBlockSize());
    if (LOG.isDebugEnabled()) {
      LOG.debug("IV read from ["
          + Base64.encodeBase64URLSafeString(iv) + "]");
    }
    return new CryptoInputStream(in, cryptoCodec, bufferSize,
        getEncryptionKey(), iv, offset + cryptoPadding(conf));
  } else {
    return in;
  }
}
 

/**
 * Wraps a given FSDataInputStream with a CryptoInputStream. The size of the
 * data buffer required for the stream is specified by the
 * "mapreduce.job.encrypted-intermediate-data.buffer.kb" Job configuration
 * variable.
 * 
 * @param conf
 * @param in
 * @return FSDataInputStream
 * @throws IOException
 */
public static FSDataInputStream wrapIfNecessary(Configuration conf,
    FSDataInputStream in) throws IOException {
  if (isEncryptedSpillEnabled(conf)) {
    CryptoCodec cryptoCodec = CryptoCodec.getInstance(conf);
    int bufferSize = getBufferSize(conf);
    // Not going to be used... but still has to be read...
    // Since the O/P stream always writes it..
    IOUtils.readFully(in, new byte[8], 0, 8);
    byte[] iv = 
        new byte[cryptoCodec.getCipherSuite().getAlgorithmBlockSize()];
    IOUtils.readFully(in, iv, 0, 
        cryptoCodec.getCipherSuite().getAlgorithmBlockSize());
    if (LOG.isDebugEnabled()) {
      LOG.debug("IV read from Stream ["
          + Base64.encodeBase64URLSafeString(iv) + "]");
    }
    return new CryptoFSDataInputStream(in, cryptoCodec, bufferSize,
        getEncryptionKey(), iv);
  } else {
    return in;
  }
}
 

/**
 * Create IOStreamPair of {@link org.apache.hadoop.crypto.CryptoInputStream}
 * and {@link org.apache.hadoop.crypto.CryptoOutputStream}
 * 
 * @param conf the configuration
 * @param cipherOption negotiated cipher option
 * @param out underlying output stream
 * @param in underlying input stream
 * @param isServer is server side
 * @return IOStreamPair the stream pair
 * @throws IOException for any error
 */
public static IOStreamPair createStreamPair(Configuration conf,
    CipherOption cipherOption, OutputStream out, InputStream in, 
    boolean isServer) throws IOException {
  if (LOG.isDebugEnabled()) {
    LOG.debug("Creating IOStreamPair of CryptoInputStream and " +
        "CryptoOutputStream.");
  }
  CryptoCodec codec = CryptoCodec.getInstance(conf, 
      cipherOption.getCipherSuite());
  byte[] inKey = cipherOption.getInKey();
  byte[] inIv = cipherOption.getInIv();
  byte[] outKey = cipherOption.getOutKey();
  byte[] outIv = cipherOption.getOutIv();
  InputStream cIn = new CryptoInputStream(in, codec, 
      isServer ? inKey : outKey, isServer ? inIv : outIv);
  OutputStream cOut = new CryptoOutputStream(out, codec, 
      isServer ? outKey : inKey, isServer ? outIv : inIv);
  return new IOStreamPair(cIn, cOut);
}
 

/**
 * Obtain a CryptoCodec based on the CipherSuite set in a FileEncryptionInfo
 * and the available CryptoCodecs configured in the Configuration.
 *
 * @param conf   Configuration
 * @param feInfo FileEncryptionInfo
 * @return CryptoCodec
 * @throws IOException if no suitable CryptoCodec for the CipherSuite is
 *                     available.
 */
private static CryptoCodec getCryptoCodec(Configuration conf,
    FileEncryptionInfo feInfo) throws IOException {
  final CipherSuite suite = feInfo.getCipherSuite();
  if (suite.equals(CipherSuite.UNKNOWN)) {
    throw new IOException("NameNode specified unknown CipherSuite with ID "
        + suite.getUnknownValue() + ", cannot instantiate CryptoCodec.");
  }
  final CryptoCodec codec = CryptoCodec.getInstance(conf, suite);
  if (codec == null) {
    throw new UnknownCipherSuiteException(
        "No configuration found for the cipher suite "
        + suite.getConfigSuffix() + " prefixed with "
        + HADOOP_SECURITY_CRYPTO_CODEC_CLASSES_KEY_PREFIX
        + ". Please see the example configuration "
        + "hadoop.security.crypto.codec.classes.EXAMPLECIPHERSUITE "
        + "at core-default.xml for details.");
  }
  return codec;
}
 

/**
 * Obtain a CryptoCodec based on the CipherSuite set in a FileEncryptionInfo
 * and the available CryptoCodecs configured in the Configuration.
 *
 * @param conf   Configuration
 * @param feInfo FileEncryptionInfo
 * @return CryptoCodec
 * @throws IOException if no suitable CryptoCodec for the CipherSuite is
 *                     available.
 */
private static CryptoCodec getCryptoCodec(Configuration conf,
    FileEncryptionInfo feInfo) throws IOException {
  final CipherSuite suite = feInfo.getCipherSuite();
  if (suite.equals(CipherSuite.UNKNOWN)) {
    throw new IOException("NameNode specified unknown CipherSuite with ID "
        + suite.getUnknownValue() + ", cannot instantiate CryptoCodec.");
  }
  final CryptoCodec codec = CryptoCodec.getInstance(conf, suite);
  if (codec == null) {
    throw new UnknownCipherSuiteException(
        "No configuration found for the cipher suite "
        + suite.getConfigSuffix() + " prefixed with "
        + HADOOP_SECURITY_CRYPTO_CODEC_CLASSES_KEY_PREFIX
        + ". Please see the example configuration "
        + "hadoop.security.crypto.codec.classes.EXAMPLECIPHERSUITE "
        + "at core-default.xml for details.");
  }
  return codec;
}
 

/**
 * O
 * btain a CryptoCodec based on the CipherSuite set in a FileEncryptionInfo
 * and the available CryptoCodecs configured in the Configuration.
 *
 * @param conf   Configuration
 * @param feInfo FileEncryptionInfo
 * @return CryptoCodec
 * @throws IOException if no suitable CryptoCodec for the CipherSuite is
 *                     available.
 */
private static CryptoCodec getCryptoCodec(Configuration conf,
                                          FileEncryptionInfo feInfo) throws IOException {
    final CipherSuite suite = feInfo.getCipherSuite();
    if (suite.equals(CipherSuite.UNKNOWN)) {
        throw new IOException("NameNode specified unknown CipherSuite with ID "
                + suite.getUnknownValue() + ", cannot instantiate CryptoCodec.");
    }
    final CryptoCodec codec = CryptoCodec.getInstance(conf, suite);
    if (codec == null) {
        throw new UnknownCipherSuiteException(
                "No configuration found for the cipher suite "
                        + suite.getConfigSuffix() + " prefixed with "
                        + HADOOP_SECURITY_CRYPTO_CODEC_CLASSES_KEY_PREFIX
                        + ". Please see the example configuration "
                        + "hadoop.security.crypto.codec.classes.EXAMPLECIPHERSUITE "
                        + "at core-default.xml for details.");
    }
    return codec;
}
 

/**
 * Wraps a given FSDataOutputStream with a CryptoOutputStream. The size of the
 * data buffer required for the stream is specified by the
 * "mapreduce.job.encrypted-intermediate-data.buffer.kb" Job configuration
 * variable.
 * 
 * @param conf
 * @param out
 * @return FSDataOutputStream
 * @throws IOException
 */
public static FSDataOutputStream wrapIfNecessary(Configuration conf,
    FSDataOutputStream out) throws IOException {
  if (isEncryptedSpillEnabled(conf)) {
    out.write(ByteBuffer.allocate(8).putLong(out.getPos()).array());
    byte[] iv = createIV(conf);
    out.write(iv);
    if (LOG.isDebugEnabled()) {
      LOG.debug("IV written to Stream ["
          + Base64.encodeBase64URLSafeString(iv) + "]");
    }
    return new CryptoFSDataOutputStream(out, CryptoCodec.getInstance(conf),
        getBufferSize(conf), getEncryptionKey(), iv);
  } else {
    return out;
  }
}
 

/**
 * Wraps a given InputStream with a CryptoInputStream. The size of the data
 * buffer required for the stream is specified by the
 * "mapreduce.job.encrypted-intermediate-data.buffer.kb" Job configuration
 * variable.
 * 
 * If the value of 'length' is > -1, The InputStream is additionally
 * wrapped in a LimitInputStream. CryptoStreams are late buffering in nature.
 * This means they will always try to read ahead if they can. The
 * LimitInputStream will ensure that the CryptoStream does not read past the
 * provided length from the given Input Stream.
 * 
 * @param conf
 * @param in
 * @param length
 * @return InputStream
 * @throws IOException
 */
public static InputStream wrapIfNecessary(Configuration conf, InputStream in,
    long length) throws IOException {
  if (isEncryptedSpillEnabled(conf)) {
    int bufferSize = getBufferSize(conf);
    if (length > -1) {
      in = new LimitInputStream(in, length);
    }
    byte[] offsetArray = new byte[8];
    IOUtils.readFully(in, offsetArray, 0, 8);
    long offset = ByteBuffer.wrap(offsetArray).getLong();
    CryptoCodec cryptoCodec = CryptoCodec.getInstance(conf);
    byte[] iv = 
        new byte[cryptoCodec.getCipherSuite().getAlgorithmBlockSize()];
    IOUtils.readFully(in, iv, 0, 
        cryptoCodec.getCipherSuite().getAlgorithmBlockSize());
    if (LOG.isDebugEnabled()) {
      LOG.debug("IV read from ["
          + Base64.encodeBase64URLSafeString(iv) + "]");
    }
    return new CryptoInputStream(in, cryptoCodec, bufferSize,
        getEncryptionKey(), iv, offset + cryptoPadding(conf));
  } else {
    return in;
  }
}
 

/**
 * Wraps a given FSDataInputStream with a CryptoInputStream. The size of the
 * data buffer required for the stream is specified by the
 * "mapreduce.job.encrypted-intermediate-data.buffer.kb" Job configuration
 * variable.
 * 
 * @param conf
 * @param in
 * @return FSDataInputStream
 * @throws IOException
 */
public static FSDataInputStream wrapIfNecessary(Configuration conf,
    FSDataInputStream in) throws IOException {
  if (isEncryptedSpillEnabled(conf)) {
    CryptoCodec cryptoCodec = CryptoCodec.getInstance(conf);
    int bufferSize = getBufferSize(conf);
    // Not going to be used... but still has to be read...
    // Since the O/P stream always writes it..
    IOUtils.readFully(in, new byte[8], 0, 8);
    byte[] iv = 
        new byte[cryptoCodec.getCipherSuite().getAlgorithmBlockSize()];
    IOUtils.readFully(in, iv, 0, 
        cryptoCodec.getCipherSuite().getAlgorithmBlockSize());
    if (LOG.isDebugEnabled()) {
      LOG.debug("IV read from Stream ["
          + Base64.encodeBase64URLSafeString(iv) + "]");
    }
    return new CryptoFSDataInputStream(in, cryptoCodec, bufferSize,
        getEncryptionKey(), iv);
  } else {
    return in;
  }
}
 

@Override
public EncryptedKeyVersion generateEncryptedKey(String encryptionKeyName)
    throws IOException, GeneralSecurityException {
  // Fetch the encryption key
  KeyVersion encryptionKey = keyProvider.getCurrentKey(encryptionKeyName);
  Preconditions.checkNotNull(encryptionKey,
      "No KeyVersion exists for key '%s' ", encryptionKeyName);
  // Generate random bytes for new key and IV

  CryptoCodec cc = CryptoCodec.getInstance(keyProvider.getConf());
  final byte[] newKey = new byte[encryptionKey.getMaterial().length];
  cc.generateSecureRandom(newKey);
  final byte[] iv = new byte[cc.getCipherSuite().getAlgorithmBlockSize()];
  cc.generateSecureRandom(iv);
  // Encryption key IV is derived from new key's IV
  final byte[] encryptionIV = EncryptedKeyVersion.deriveIV(iv);
  Encryptor encryptor = cc.createEncryptor();
  encryptor.init(encryptionKey.getMaterial(), encryptionIV);
  int keyLen = newKey.length;
  ByteBuffer bbIn = ByteBuffer.allocateDirect(keyLen);
  ByteBuffer bbOut = ByteBuffer.allocateDirect(keyLen);
  bbIn.put(newKey);
  bbIn.flip();
  encryptor.encrypt(bbIn, bbOut);
  bbOut.flip();
  byte[] encryptedKey = new byte[keyLen];
  bbOut.get(encryptedKey);    
  return new EncryptedKeyVersion(encryptionKeyName,
      encryptionKey.getVersionName(), iv,
      new KeyVersion(encryptionKey.getName(), EEK, encryptedKey));
}
 

@BeforeClass
public static void init() throws Exception {
  Configuration conf = new HdfsConfiguration();
  dfsCluster = new MiniDFSCluster.Builder(conf).build();
  dfsCluster.waitClusterUp();
  fs = dfsCluster.getFileSystem();
  codec = CryptoCodec.getInstance(conf);
}
 

@Override
public KeyVersion decryptEncryptedKey(
    EncryptedKeyVersion encryptedKeyVersion) throws IOException,
    GeneralSecurityException {
  // Fetch the encryption key material
  final String encryptionKeyVersionName =
      encryptedKeyVersion.getEncryptionKeyVersionName();
  final KeyVersion encryptionKey =
      keyProvider.getKeyVersion(encryptionKeyVersionName);
  Preconditions.checkNotNull(encryptionKey,
      "KeyVersion name '%s' does not exist", encryptionKeyVersionName);
  Preconditions.checkArgument(
          encryptedKeyVersion.getEncryptedKeyVersion().getVersionName()
                .equals(KeyProviderCryptoExtension.EEK),
            "encryptedKey version name must be '%s', is '%s'",
            KeyProviderCryptoExtension.EEK,
            encryptedKeyVersion.getEncryptedKeyVersion().getVersionName()
        );

  // Encryption key IV is determined from encrypted key's IV
  final byte[] encryptionIV =
      EncryptedKeyVersion.deriveIV(encryptedKeyVersion.getEncryptedKeyIv());

  CryptoCodec cc = CryptoCodec.getInstance(keyProvider.getConf());
  Decryptor decryptor = cc.createDecryptor();
  decryptor.init(encryptionKey.getMaterial(), encryptionIV);
  final KeyVersion encryptedKV =
      encryptedKeyVersion.getEncryptedKeyVersion();
  int keyLen = encryptedKV.getMaterial().length;
  ByteBuffer bbIn = ByteBuffer.allocateDirect(keyLen);
  ByteBuffer bbOut = ByteBuffer.allocateDirect(keyLen);
  bbIn.put(encryptedKV.getMaterial());
  bbIn.flip();
  decryptor.decrypt(bbIn, bbOut);
  bbOut.flip();
  byte[] decryptedKey = new byte[keyLen];
  bbOut.get(decryptedKey);
  return new KeyVersion(encryptionKey.getName(), EK, decryptedKey);
}
 

/**
 * Negotiate a cipher option which server supports.
 * 
 * @param conf the configuration
 * @param options the cipher options which client supports
 * @return CipherOption negotiated cipher option
 */
public static CipherOption negotiateCipherOption(Configuration conf,
    List<CipherOption> options) throws IOException {
  // Negotiate cipher suites if configured.  Currently, the only supported
  // cipher suite is AES/CTR/NoPadding, but the protocol allows multiple
  // values for future expansion.
  String cipherSuites = conf.get(DFS_ENCRYPT_DATA_TRANSFER_CIPHER_SUITES_KEY);
  if (cipherSuites == null || cipherSuites.isEmpty()) {
    return null;
  }
  if (!cipherSuites.equals(CipherSuite.AES_CTR_NOPADDING.getName())) {
    throw new IOException(String.format("Invalid cipher suite, %s=%s",
        DFS_ENCRYPT_DATA_TRANSFER_CIPHER_SUITES_KEY, cipherSuites));
  }
  if (options != null) {
    for (CipherOption option : options) {
      CipherSuite suite = option.getCipherSuite();
      if (suite == CipherSuite.AES_CTR_NOPADDING) {
        int keyLen = conf.getInt(
            DFS_ENCRYPT_DATA_TRANSFER_CIPHER_KEY_BITLENGTH_KEY,
            DFS_ENCRYPT_DATA_TRANSFER_CIPHER_KEY_BITLENGTH_DEFAULT) / 8;
        CryptoCodec codec = CryptoCodec.getInstance(conf, suite);
        byte[] inKey = new byte[keyLen];
        byte[] inIv = new byte[suite.getAlgorithmBlockSize()];
        byte[] outKey = new byte[keyLen];
        byte[] outIv = new byte[suite.getAlgorithmBlockSize()];
        codec.generateSecureRandom(inKey);
        codec.generateSecureRandom(inIv);
        codec.generateSecureRandom(outKey);
        codec.generateSecureRandom(outIv);
        return new CipherOption(suite, inKey, inIv, outKey, outIv);
      }
    }
  }
  return null;
}
 

/**
 * This method creates and initializes an IV (Initialization Vector)
 * 
 * @param conf
 * @return byte[]
 * @throws IOException
 */
public static byte[] createIV(Configuration conf) throws IOException {
  CryptoCodec cryptoCodec = CryptoCodec.getInstance(conf);
  if (isEncryptedSpillEnabled(conf)) {
    byte[] iv = new byte[cryptoCodec.getCipherSuite().getAlgorithmBlockSize()];
    cryptoCodec.generateSecureRandom(iv);
    return iv;
  } else {
    return null;
  }
}
 

@Override
public EncryptedKeyVersion generateEncryptedKey(String encryptionKeyName)
    throws IOException, GeneralSecurityException {
  // Fetch the encryption key
  KeyVersion encryptionKey = keyProvider.getCurrentKey(encryptionKeyName);
  Preconditions.checkNotNull(encryptionKey,
      "No KeyVersion exists for key '%s' ", encryptionKeyName);
  // Generate random bytes for new key and IV

  CryptoCodec cc = CryptoCodec.getInstance(keyProvider.getConf());
  final byte[] newKey = new byte[encryptionKey.getMaterial().length];
  cc.generateSecureRandom(newKey);
  final byte[] iv = new byte[cc.getCipherSuite().getAlgorithmBlockSize()];
  cc.generateSecureRandom(iv);
  // Encryption key IV is derived from new key's IV
  final byte[] encryptionIV = EncryptedKeyVersion.deriveIV(iv);
  Encryptor encryptor = cc.createEncryptor();
  encryptor.init(encryptionKey.getMaterial(), encryptionIV);
  int keyLen = newKey.length;
  ByteBuffer bbIn = ByteBuffer.allocateDirect(keyLen);
  ByteBuffer bbOut = ByteBuffer.allocateDirect(keyLen);
  bbIn.put(newKey);
  bbIn.flip();
  encryptor.encrypt(bbIn, bbOut);
  bbOut.flip();
  byte[] encryptedKey = new byte[keyLen];
  bbOut.get(encryptedKey);    
  return new EncryptedKeyVersion(encryptionKeyName,
      encryptionKey.getVersionName(), iv,
      new KeyVersion(encryptionKey.getName(), EEK, encryptedKey));
}
 

@BeforeClass
public static void init() throws Exception {
  Configuration conf = new HdfsConfiguration();
  dfsCluster = new MiniDFSCluster.Builder(conf).build();
  dfsCluster.waitClusterUp();
  fs = dfsCluster.getFileSystem();
  codec = CryptoCodec.getInstance(conf);
}
 

/**
 * Negotiate a cipher option which server supports.
 * 
 * @param conf the configuration
 * @param options the cipher options which client supports
 * @return CipherOption negotiated cipher option
 */
public static CipherOption negotiateCipherOption(Configuration conf,
    List<CipherOption> options) throws IOException {
  // Negotiate cipher suites if configured.  Currently, the only supported
  // cipher suite is AES/CTR/NoPadding, but the protocol allows multiple
  // values for future expansion.
  String cipherSuites = conf.get(DFS_ENCRYPT_DATA_TRANSFER_CIPHER_SUITES_KEY);
  if (cipherSuites == null || cipherSuites.isEmpty()) {
    return null;
  }
  if (!cipherSuites.equals(CipherSuite.AES_CTR_NOPADDING.getName())) {
    throw new IOException(String.format("Invalid cipher suite, %s=%s",
        DFS_ENCRYPT_DATA_TRANSFER_CIPHER_SUITES_KEY, cipherSuites));
  }
  if (options != null) {
    for (CipherOption option : options) {
      CipherSuite suite = option.getCipherSuite();
      if (suite == CipherSuite.AES_CTR_NOPADDING) {
        int keyLen = conf.getInt(
            DFS_ENCRYPT_DATA_TRANSFER_CIPHER_KEY_BITLENGTH_KEY,
            DFS_ENCRYPT_DATA_TRANSFER_CIPHER_KEY_BITLENGTH_DEFAULT) / 8;
        CryptoCodec codec = CryptoCodec.getInstance(conf, suite);
        byte[] inKey = new byte[keyLen];
        byte[] inIv = new byte[suite.getAlgorithmBlockSize()];
        byte[] outKey = new byte[keyLen];
        byte[] outIv = new byte[suite.getAlgorithmBlockSize()];
        codec.generateSecureRandom(inKey);
        codec.generateSecureRandom(inIv);
        codec.generateSecureRandom(outKey);
        codec.generateSecureRandom(outIv);
        return new CipherOption(suite, inKey, inIv, outKey, outIv);
      }
    }
  }
  return null;
}
 

/**
 * This method creates and initializes an IV (Initialization Vector)
 * 
 * @param conf
 * @return byte[]
 * @throws IOException
 */
public static byte[] createIV(Configuration conf) throws IOException {
  CryptoCodec cryptoCodec = CryptoCodec.getInstance(conf);
  if (isEncryptedSpillEnabled(conf)) {
    byte[] iv = new byte[cryptoCodec.getCipherSuite().getAlgorithmBlockSize()];
    cryptoCodec.generateSecureRandom(iv);
    return iv;
  } else {
    return null;
  }
}