DES Crypter And Decryper File : File Secure IO « Security « Java

1. Java
2. Security
3. File Secure IO

DES Crypter And Decryper File

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Security;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;

public class MainClass {
  static Cipher m_encrypter;

  static Cipher m_decrypter;

  public static void main(String args[]) throws Exception {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

    SecretKey key = KeyGenerator.getInstance("DES").generateKey();

    // for CBC; must be 8 bytes
    byte[] initVector = new byte[] { 0x10, 0x10, 0x01, 0x04, 0x01, 0x01, 0x01, 0x02 };

    AlgorithmParameterSpec algParamSpec = new IvParameterSpec(initVector);
    Cipher m_encrypter = Cipher.getInstance("DES/CBC/PKCS5Padding");
    Cipher m_decrypter = Cipher.getInstance("DES/CBC/PKCS5Padding");

    m_encrypter.init(Cipher.ENCRYPT_MODE, key, algParamSpec);
    m_decrypter.init(Cipher.DECRYPT_MODE, key, algParamSpec);

    FileInputStream fis = new FileInputStream("cipherTest.in");
    FileOutputStream fos = new FileOutputStream("cipherTest.out");
    int dataInputSize = fis.available();

    byte[] inputBytes = new byte[dataInputSize];
    fis.read(inputBytes);
    write(inputBytes, fos);
    fos.flush();
    fis.close();
    fos.close();

    String inputFileAsString = new String(inputBytes);
    System.out.println("INPUT FILE CONTENTS\n" + inputFileAsString + "\n");

    System.out.println("File encrypted and saved to disk\n");

    fis = new FileInputStream("cipherTest.out");

    byte[] decrypted = new byte[dataInputSize];
    read(decrypted, fis);

    fis.close();
    String decryptedAsString = new String(decrypted);

    System.out.println("DECRYPTED FILE:\n" + decryptedAsString + "\n");

  }

  public static void write(byte[] bytes, OutputStream out) throws Exception {
    CipherOutputStream cos = new CipherOutputStream(out, m_encrypter);
    cos.write(bytes, 0, bytes.length);
    cos.close();
  }

  public static void read(byte[] bytes, InputStream in) throws Exception {
    CipherInputStream cis = new CipherInputStream(in, m_decrypter);
    int pos = 0, intValue;

    while ((intValue = cis.read()) != -1) {
      bytes[pos] = (byte) intValue;
      pos++;
    }
  }

}
           
       

DESCrypterAndDecryperFile.zip( 1,199 k)

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