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Use DES to Decrypt

import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import javax.crypto.Cipher; import javax.crypto.CipherInputStream; import javax.crypto.SecretKey; public class MainClass {   public static void main(String[] args) throws Exception {     desEncrypt("plaintextfile", "ciphertextfile");   }   public static void desEncrypt(String f1, String f2) throws Exception {     SecretKey key = null;     ObjectInputStream keyFile = new ObjectInputStream(new FileInputStream("DESKey.ser"));     key = (SecretKey) keyFile.readObject();     keyFile.close();     Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");     cipher.init(Cipher.DECRYPT_MODE, key);     CipherInputStream in = new CipherInputStream(new BufferedInputStream(new FileInputStream(f1)),         cipher);     BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(f2));     int i;     do {       i = in.read();       if (i != -1)         out.write(i);     } while (i > 0);     in.close();     out.close();   } }