How to use

CipherInputStream

in

javax.crypto

/**
 * Returns the input stream for reading the previously written encrypted data
 *
 * @return the inputstream
 * @throws IOException if the reading of the underlying file fails
 */
public InputStream getInputStream() throws IOException {
  Cipher ciDec = CryptoFunctions.getCipher(skeySpec, cipherAlgorithm, ChainingMode.cbc, ivBytes, Cipher.DECRYPT_MODE, PADDING);
  return new CipherInputStream(new FileInputStream(tempFile), ciDec);
}

 static void decrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
  FileInputStream fis = new FileInputStream("data/encrypted");

  FileOutputStream fos = new FileOutputStream("data/decrypted");
  SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(), "AES");
  Cipher cipher = Cipher.getInstance("AES");
  cipher.init(Cipher.DECRYPT_MODE, sks);
  CipherInputStream cis = new CipherInputStream(fis, cipher);
  int b;
  byte[] d = new byte[8];
  while((b = cis.read(d)) != -1) {
    fos.write(d, 0, b);
  }
  fos.flush();
  fos.close();
  cis.close();
}

private void crypt(InputStream in, OutputStream out, byte[] keyBytes, byte[] iv, int cryptMode) throws CryptoException {
  if (in == null) {
    throw new NullPointerException("InputStream argument cannot be null.");
  }
  if (out == null) {
    throw new NullPointerException("OutputStream argument cannot be null.");
  }
  javax.crypto.Cipher cipher = initNewCipher(cryptMode, keyBytes, iv, true);
  CipherInputStream cis = new CipherInputStream(in, cipher);
  int bufSize = getStreamingBufferSize();
  byte[] buffer = new byte[bufSize];
  int bytesRead;
  try {
    while ((bytesRead = cis.read(buffer)) != -1) {
      out.write(buffer, 0, bytesRead);
    }
  } catch (IOException e) {
    throw new CryptoException(e);
  }
}

mEcipher.init (Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = mEcipher.getParameters ();
mDecipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(mInitVec));
byte [] inbuf = new byte [MAX_FILE_BUF];
fout = new FileOutputStream (output);
fin = new FileInputStream (input);
while ((nread = fin.read (inbuf)) > 0 )
    fout.write (tmp);
byte [] finalbuf = mEcipher.doFinal ();
if (finalbuf != null)
  fout.write (finalbuf);
while ((nread = cin.read (inbuf)) > 0 )
fout.flush();
cin.close();
fin.close ();       
fout.close();   

FileInputStream fis = new FileInputStream(new File("D:/Shashank/inputVideo.avi"));
   File outfile = new File("D:/Shashank/encVideo.avi");
   int read;
   if(!decfile.exists())
     decfile.createNewFile();
   FileOutputStream fos = new FileOutputStream(outfile);
   FileInputStream encfis = new FileInputStream(outfile);
   FileOutputStream decfos = new FileOutputStream(decfile);
   Cipher encipher = Cipher.getInstance("AES");
   Cipher decipher = Cipher.getInstance("AES");
   encipher.init(Cipher.ENCRYPT_MODE, skey);
   CipherInputStream cis = new CipherInputStream(fis, encipher);
   decipher.init(Cipher.DECRYPT_MODE, skey);
   CipherOutputStream cos = new CipherOutputStream(decfos,decipher);
   while((read = cis.read())!=-1)
         fos.write((char)read);
         fos.flush();
   fos.close();
   while((read=encfis.read())!=-1)

public static void decryptFile(File src, File dst, String passwd, String iv) throws Exception {
  if (!dst.getParentFile().exists())
    dst.getParentFile().mkdirs();
  byte[] _iv = StringUtils.getHexBytes(iv);
  IvParameterSpec _spec = new IvParameterSpec(_iv);
  byte[] _keyBytes = HashFunctions.getSHAHashBytes(passwd.getBytes());
  SecretKeySpec _key = new SecretKeySpec(_keyBytes, "AES");
  Cipher encrypt = Cipher.getInstance("AES/CBC/PKCS5Padding");
  encrypt.init(Cipher.DECRYPT_MODE, _key, _spec);
  // opening streams
  FileOutputStream fos = new FileOutputStream(dst);
  FileInputStream fis = new FileInputStream(src);
  CipherInputStream cis = new CipherInputStream(fis, encrypt);
  IOUtils.copy(cis, fos);
  fos.flush();
  fos.close();
  cis.close();
}

protected void transferFileData(File inputFile, File outputFile, Cipher cipher) throws IOException {
  InputStream is = null;
  OutputStream os = null;
  try {
    os = new BufferedOutputStream(new FileOutputStream(outputFile));
    is = new CipherInputStream(new BufferedInputStream(new FileInputStream(inputFile)), cipher);
    byte[] buffer = new byte[16384];
    int read = -1;
    while ((read = is.read(buffer)) != -1) {
      os.write(buffer, 0, read);
    }
  } finally {
    if (os != null)
      os.close();
    if (is != null)
      is.close();
  }
}

 FileInputStream inputStream = new FileInputStream(inputFile);
FileOutputStream fileOutputStream = new FileOutputStream(outputFile);

int read;

CipherInputStream cis = new CipherInputStream(inputStream, cipher);

while ((read = cis.read()) != -1) {
  fileOutputStream.write(read);
}
fileOutputStream.close();
cis.close();

cipher.init(Cipher.ENCRYPT_MODE, secretKey);
FileInputStream fis = new FileInputStream(System.getProperty("user.home") + java.io.File.separatorChar + "plain.pdf");
FileOutputStream fos = new FileOutputStream(System.getProperty("user.home") + java.io.File.separatorChar + "test.enc");
final CipherOutputStream output = new CipherOutputStream(fos, cipher);
while ((bytesRead = fis.read(plainText)) >= 0) {
  output.write(plainText, 0, bytesRead);
fos.close();
fis.close();
final byte[] iv = cipher.getIV();
cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(iv));
fis = new FileInputStream(System.getProperty("user.home") + java.io.File.separatorChar + "test.enc");
fos = new FileOutputStream(System.getProperty("user.home") + java.io.File.separatorChar + "test.pdf");
final CipherInputStream input = new CipherInputStream(fis, cipher);
while ((decryptedRead = input.read(decryptedData)) >= 0) {
  fos.write(decryptedData, 0, decryptedRead);
fos.flush();
fos.close();
input.close();
fis.close();

 byte[] salt = { (byte) 0xc7, (byte) 0x73, (byte) 0x21, (byte) 0x8c,
    (byte) 0x7e, (byte) 0xc8, (byte) 0xee, (byte) 0x99 };
fileinputstrm = new FileInputStream(path);

PBEKeySpec pbeKeySpec = new PBEKeySpec("pass".toCharArray());

PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, 20);
SecretKeyFactory keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);

Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);

FileInputStream fis=new FileInputStream(path);
CipherInputStream cis=new CipherInputStream(fis, pbeCipher);
BufferedInputStream bfi=new BufferedInputStream(cis);
bfi.read();
cis.close();
FileOutputStream output1 = new FileOutputStream(path+".jpeg");
ByteArrayOutputStream baos=new ByteArrayOutputStream();
BufferedOutputStream bfo=new BufferedOutputStream(output1);
output1.write(baos.toByteArray());

SecretKey sk = kg.generateKey();
Cipher cipher = Cipher.getInstance(TEST_CIPHER);
cipher.init(Cipher.ENCRYPT_MODE, sk);
System.out.println("IV: " + new String(Base64.encodeBase64(cipher.getIV()), "US-ASCII"));
CipherOutputStream out = new CipherOutputStream(new FileOutputStream(new File(outfile)), cipher);
InputStream in = new FileInputStream(new File(infile));
String outfile = args[4];
SecretKeySpec sk = new SecretKeySpec(Base64.decodeBase64(key.getBytes("US-ASCII")), "AES");
IvParameterSpec ivspec = new IvParameterSpec(Base64.decodeBase64(iv.getBytes("US-ASCII")));
Cipher cipher = Cipher.getInstance(TEST_CIPHER);
cipher.init(Cipher.DECRYPT_MODE, sk, ivspec);
CipherInputStream in = new CipherInputStream(new FileInputStream(new File(infile)), cipher);
OutputStream out = new FileOutputStream(new File(outfile));
out.close();
in.close();

 // get cipher object for password-based encryption
Cipher cipher1 = Cipher.getInstance("PBEWithMD5AndDES");//You have to pass here algorithm name which PGP uses. May be you have to find and init provider for it.

// initialize cipher for decryption, using one of the 
// init() methods that takes an AlgorithmParameters 
// object, and pass it the algParams object from above
cipher1.init(Cipher.DECRYPT_MODE, myKey, algParams);


FileInputStream fis;
FileOutputStream fos;
CipherInputStream cis;

fis = new FileInputStream("/tmp/a.txt");
cis = new CipherInputStream(fis, cipher1);
fos = new FileOutputStream("/tmp/b.txt");
byte[] b = new byte[8];
int i = cis.read(b);
while (i != -1) {
  fos.write(b, 0, i);
  i = cis.read(b);
}
fos.close();

inCipher.init(Cipher.ENCRYPT_MODE, publicKey);
outCipher.init(Cipher.DECRYPT_MODE, privateKey);
    new FileOutputStream(encryptedDataFilePath), inCipher);
cipherOutputStream.write(plainText.getBytes("UTF-8"));
cipherOutputStream.close();
  new CipherInputStream(new FileInputStream(encryptedDataFilePath),
    outCipher);
byte [] roundTrippedBytes = new byte[1000]; // TODO: dynamically resize as we get more data
while ((nextByte = cipherInputStream.read()) != -1) {
  roundTrippedBytes[index] = (byte)nextByte;
  index++;

InputStream is = new FileInputStream(in);
if (is.read(bufferKey) != bufferKey.length) { 
  is.close();
cipher.init(Cipher.UNWRAP_MODE, priv);
Key aesKey = cipher.unwrap(bufferKey, "AES", Cipher.SECRET_KEY);
cipher.init(Cipher.DECRYPT_MODE, aesKey);
FileOutputStream os = new FileOutputStream(out);
ix.close();
os.close();

public void decrypt(File in, File out) throws IOException, InvalidKeyException {
 aesCipher.init(Cipher.DECRYPT_MODE, aeskeySpec);
 CipherInputStream is = new CipherInputStream(new FileInputStream(in), aesCipher);
 FileOutputStream os = new FileOutputStream(out);
 int i;
 byte[] b = new byte[1024];
 while((i=is.read(b))!=-1) {
     os.write(b, 0, i);
 }

/**
 * @param keyLength
 *      Block size of the asymmetric cipher, in bits. I thought I can get it from {@code asym.getBlockSize()}
 *      but that doesn't work with Sun's implementation.
 */
public CombinedCipherInputStream(InputStream in, Cipher asym, String algorithm, int keyLength) throws IOException, GeneralSecurityException {
  super(in);
  String keyAlgorithm = getKeyAlgorithm(algorithm);
  // first read the symmetric key cipher
  byte[] symKeyBytes = new byte[keyLength/8];
  new DataInputStream(in).readFully(symKeyBytes);
  SecretKey symKey = new SecretKeySpec(asym.doFinal(symKeyBytes),keyAlgorithm);
  // the rest of the data will be decrypted by this symmetric cipher
  Cipher sym = Secret.getCipher(algorithm);
  sym.init(Cipher.DECRYPT_MODE,symKey, keyAlgorithm.equals(algorithm) ? null : new IvParameterSpec(symKey.getEncoded()));
  super.in = new CipherInputStream(in,sym);
}

/**
 * 解密文件
 *
 * @param in
 */
public void doDecryptFile(InputStream in, String path) {
  if (in == null) {
    System.out.println("inputstream is null");
    return;
  }
  try {
    CipherInputStream cin = new CipherInputStream(in, mDecryptCipher);
    OutputStream outputStream = new FileOutputStream(path);
    byte[] bytes = new byte[1024];
    int length = -1;
    while ((length = cin.read(bytes)) > 0) {
      outputStream.write(bytes, 0, length);
      outputStream.flush();
    }
    cin.close();
    in.close();
    System.out.println("解密成功");
  } catch (Exception e) {
    System.out.println("解密失败");
    e.printStackTrace();
  }
}

CipherInputStream c_decf = new CipherInputStream(decf, decipher);
 FileOutputStream destf = new FileOutputStream(destfile);
 //CipherOutputStream cout = new CipherOutputStream(destf, decipher);
 while ((read = c_decf.read()) != -1) {
   destf.write(read);
   destf.flush();
 }
 c_decf.close();
 destf.close();
 // cout.close();
 decf.close();

byte[] wholeFileByte = null;
 Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
 cipher.init(Cipher.DECRYPT_MODE, key, DownloadBookAsyncTask.ivspec);
 File file = new File(context.getFilesDir().getParentFile().getPath() + "/download/" + id + "/xmldata.xml");
 FileInputStream fis = new FileInputStream(file);
 ByteArrayOutputStream bos = new ByteArrayOutputStream();
 CipherInputStream cis = new CipherInputStream(fis, cipher);
 byte data[] = new byte[4096];
 int count;
 while ((count = cis.read(data)) != -1) {
   bos.write(data, 0, count);
 }
 if(cis != null)
   cis.close();
 if(bos != null)
   bos.close();
 if(fis != null)
   fis.close();
 wholeFileByte = bos.toByteArray();
 String kk = new String(wholeFileByte, "UTF-8");

 public void decrypt(String filename) throws Exception {
  BufferedInputStream bis = new BufferedInputStream(new FileInputStream("filename"));
  Base64InputStream base64Stream = new Base64InputStream(bis, 0);
  Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
  CipherInputStream cis = new CipherInputStream(base64Stream, c);
  byte[] plainBuf = new byte[2048];
  int nRead;
  while ((nRead = cis.read(plainBuf)) > 0) {
    // send plainBuf[0] through plainBuf[nRead-1] to the video codec
  }
  cis.close();
}