Java實現DESede(雙重DES)對檔案加密

 

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

/*
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 * and open the template in the editor.
 */

/**
 *
 * @author Administrator
 */
public class GenKey {
    public static void main(String[] args){//產生密鑰
            //將密鑰儲存在檔案中
        try {
            KeyGenerator keyGen = KeyGenerator.getInstance("DESede");
            //初始化金鑰產生器
            keyGen.init(168);
            //產生密鑰
            SecretKey key = keyGen.generateKey(); //以二進位檔案流形式儲存
            //將密鑰儲存在檔案中
            FileOutputStream f = new FileOutputStream("key3.dat");
            ObjectOutputStream b = new ObjectOutputStream(f);
            b.writeObject(key);
            f.close();
            b.close();
        } catch (Exception ex) {
            Logger.getLogger(GenKey.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

}

 

 

 

 

 

 /*
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 * and open the template in the editor.
 */

package cipherinputstream;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.security.Key;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;

/**
 *
 * @author Administrator
 */
public class EncryptAndDecrypt {
    public static  void main(String[] args){
        //要用作加密或解密的檔案名稱
        String dataFileName=args[0];
        //是區分是加密還是解密，加密為encrypt,解密為decrypt
        String opMode=args[1];
        //密鑰存放的檔案名稱
        String keyFileName="key.dat";
        try {
            //產生密鑰
            FileInputStream keyFIS = new FileInputStream(keyFileName);
            ObjectInputStream OIS=new ObjectInputStream(keyFIS);
            Key key=(Key)OIS.readObject();
            //建立並初始化密碼器
            Cipher cp=Cipher.getInstance("DESede");
            if(opMode.equalsIgnoreCase("encrypt")){
                cp.init(Cipher.ENCRYPT_MODE, key);
            }
            else if(opMode.equalsIgnoreCase("decrypt")){
                cp.init(Cipher.DECRYPT_MODE, key);
            }
            else return;

            //建立CipherInputStream對象
            FileInputStream dataFIS=new FileInputStream(dataFileName);
            CipherInputStream CIS=new CipherInputStream(dataFIS,cp);
            //如果是加密操作
            if(opMode.equalsIgnoreCase("encrypt")){
                //建立檔案輸出資料流
                FileOutputStream FOS=new FileOutputStream("mi.txt");
                int b=0;
                System.out.print("加密後的密文是：");
                while((b=CIS.read())!=-1){
                    System.out.print((char)b);
                    FOS.write((byte)b);
                }
                System.out.println("/n密文已經寫到檔案裡。");
            }
            else{//如果是解密操作
                int b=0;
                FileOutputStream FOS=new FileOutputStream("jiemi.txt");
                System.out.print("解密後的明文是：");
                while((b=CIS.read())!=-1){
                    FOS.write(b);//寫入檔案中

                }
            }
        } catch (Exception ex) {
            Logger.getLogger(EncryptAndDecrypt.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

}