Blowfish

Örnek

Elimizde şöyle bir kod olsun

// random blowfish 256 key
byte[] key = new byte[32];
SecureRandom secureRandom = new SecureRandom();
secureRandom.nextBytes(key);


// random iv
byte[] iv = new byte[8]; // blowfish iv is 8 bytes long
secureRandom.nextBytes(iv);

Bir dosyayı okuyup başka dosyaya şifrelenmiş olarak yazmak için şöyle yaparız

public static boolean encryptCbcFileBufferedCipherOutputStream(String inputFilename,
  String outputFilename, byte[] key, byte[] iv)
throws IOException, NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException,
    InvalidAlgorithmParameterException {
  Cipher cipher = Cipher.getInstance("Blowfish/CBC/PKCS5Padding");
  try (FileInputStream in = new FileInputStream(inputFilename);
    FileOutputStream out = new FileOutputStream(outputFilename);
    CipherOutputStream encryptedOutputStream = new CipherOutputStream(out, cipher);) {
    out.write(iv);
    SecretKeySpec secretKeySpec = new SecretKeySpec(key, "Blowfish");
    IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
    cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
    byte[] buffer = new byte[8096];
    int nread;
    while ((nread = in.read(buffer)) > 0) {
      encryptedOutputStream.write(buffer, 0, nread);
    }
    encryptedOutputStream.flush();
  }
}

Şifrelenmiş dosyayı okumak için şöyle yaparız

public static boolean decryptCbcFileBufferedCipherInputStream(String inputFilename,
  String outputFilename, byte[] key)
throws IOException, NoSuchPaddingException, NoSuchAlgorithmException,
    InvalidKeyException, InvalidAlgorithmParameterException {
  byte[] iv = new byte[8]; // blowfish iv is 8 bytes long
  Cipher cipher = Cipher.getInstance("Blowfish/CBC/PKCS5Padding");
  try (FileInputStream in = new FileInputStream(inputFilename);
    CipherInputStream cipherInputStream = new CipherInputStream(in, cipher);
    FileOutputStream out = new FileOutputStream(outputFilename)) {
      byte[] buffer = new byte[8192];
      in.read(iv);
      SecretKeySpec secretKeySpec = new SecretKeySpec(key, "Blowfish");
      IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
      cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
      int nread;
      while ((nread = cipherInputStream.read(buffer)) > 0) {
        out.write(buffer, 0, nread);
      }
      out.flush();
    }
}