import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
/**
 * 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);
}
 

import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
/**
 * Wraps the stream in a CryptoInputStream if the underlying file is
 * encrypted.
 */
public HdfsDataInputStream createWrappedInputStream(DFSInputStream dfsis)
    throws IOException {
  final FileEncryptionInfo feInfo = dfsis.getFileEncryptionInfo();
  if (feInfo != null) {
    // File is encrypted, wrap the stream in a crypto stream.
    // Currently only one version, so no special logic based on the version #
    getCryptoProtocolVersion(feInfo);
    final CryptoCodec codec = getCryptoCodec(conf, feInfo);
    final KeyVersion decrypted = decryptEncryptedDataEncryptionKey(feInfo);
    final CryptoInputStream cryptoIn =
        new CryptoInputStream(dfsis, codec, decrypted.getMaterial(),
            feInfo.getIV());
    return new HdfsDataInputStream(cryptoIn);
  } else {
    // No FileEncryptionInfo so no encryption.
    return new HdfsDataInputStream(dfsis);
  }
}
 

import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
/**
 * 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 {
  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);
}
 

import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
public CryptoFSDataInputStream(FSDataInputStream in, CryptoCodec codec, 
    int bufferSize, byte[] key, byte[] iv) throws IOException {
  super(new CryptoInputStream(in, codec, bufferSize, key, iv)); 
}
 

import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
public HdfsDataInputStream(CryptoInputStream in) throws IOException {
  super(in);
  Preconditions.checkArgument(in.getWrappedStream() instanceof DFSInputStream,
      "CryptoInputStream should wrap a DFSInputStream");
}
 

import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
private DFSInputStream getDFSInputStream() {
  if (in instanceof CryptoInputStream) {
    return (DFSInputStream) ((CryptoInputStream) in).getWrappedStream();
  }
  return (DFSInputStream) in;
}
 

import org.apache.hadoop.crypto.CryptoInputStream; //导入依赖的package包/类
public HdfsDataInputStream(CryptoInputStream in) {
  super(in);
  Preconditions.checkArgument(in.getWrappedStream() instanceof DFSInputStream,
      "CryptoInputStream should wrap a DFSInputStream");
}