Why the Decrypted message disordered

Question

THAT IS MY ASSIGNMENT WORKS
(a) Write the program GenKey so that when the following statement is executed:
java GenKey abc1234 c:\key.dat
java Encrypt c:\key.dat c:\inputfile.dat c:\outputfile.dat
java Decrypt c:\key.dat c:\inputfile.dat c:\outputfile.dat
Then, a DES key will be read from the location c:\key.dat and the input file at c:\inputfile.dat will be read and decrypted using the DES command. The output will be written to the file at c:\outputfile.dat.
The result and code as follows, I don't know why totally! When I use FileOutputStream, decrypted unsucessful due to pedding mismatch, BUT USING DataInputput/OutputSream, the result as follows.
Original code
Hong Kong Welcomes You
Encypted message
Ðý?$šg?„rêg’ú?ÿ?7ºþnss �æ‚i+
Decypted file
es YouHong Kong Welcomes
Edited by: Jeckys_Rocket on May 6, 2008 7:09 AM
import java.io.*;*
*import java.security.*;
import javax.crypto.*;*
*public class Encrypt {*
*private Cipher encryptCipher = null;*
*private Cipher decryptCipher = null;*
*public Encrypt(String args []) {*
*javax.crypto.SecretKey key=null;*
*try {*
*// byte[] re=cipher.doFinal(this.message.getText().getBytes());*
*ObjectInputStream input=new ObjectInputStream(new FileInputStream(args [0]));*
*key=(SecretKey)input.readObject();*
*encryptCipher = Cipher.getInstance("DES");*
*encryptCipher.init(Cipher.ENCRYPT_MODE, key);*
*decryptCipher = Cipher.getInstance("DES");*
*decryptCipher.init(Cipher.DECRYPT_MODE, key);*
*DataOutputStream dataOutputStream = new DataOutputStream (new FileOutputStream(new File(args[2])));*
*DataInputStream dataInputStream = new DataInputStream( new FileInputStream(args[1]));*
*DataInputStream dataInputStreamt = new DataInputStream( new FileInputStream(args[1]));*
*int cout=0;*
*byte [] bc=null;*
*String temp="";*
*String name="";*
*try{*
*// for(int i=0;i<10;i++){*
*for(;(dataInputStreamt.read())!=-1;){*
*cout++;*
*bc=new byte [cout];*
*int temps=dataInputStream.read(bc);*
*// if(temp==null)*
*// {break;}*
*// name=name+temp;*
*}catch(IOException e){*
*e.printStackTrace();*
*//String name=temp;*
*name =new String(bc);*
*name=new String(bc);*
*System.out.println("see "+name+""+bc.length);*
*//name=temp;*
*FileOutputStream dos = new FileOutputStream(new File(args[2]));*
*// int rs=0;*
*// byte [] b=new byte [1000];*
*// rs=0;*
*/* for (int i=0;(rs = dis.read()) != -1;i++)
b=(byte)rs;
*// for(int i=0;i<b[i];i++){*
*// b[i]=b[i];}*
*// String strp=new String(b);*
System.out.println("plain "+ name+" end plain");
byte [] encypted=encryptCipher.update(name.getBytes());
encypted=encryptCipher.doFinal(name.getBytes());
String strp=new String(encypted);
System.out.println("EN "+ strp);
byte [] de= decryptCipher.doFinal(strp.getBytes());
String str1="";
str1=new String(de);
System.out.println("decypted "+str1);
dos.write(strp.getBytes());
dataOutputStream.write(strp.getBytes());
*/* if (dis != null) dis.close();
if (dos != null) dos.close();*/
catch (Exception e) {
e.printStackTrace();
System.out.println("File not found: " + args[0]);
public static void main(String [] args){
Encrypt e=new Encrypt(args);
WHAT IS WRONG?
Edited by: Jeckys_Rocket on May 6, 2008 7:18 AM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

There is so much wrong that I won't detail the problems. To encrypt you should be following
1) Open the source file with a FileInputStream.
2) Open the output file with a FileOutputStream.
3) Wrap the FileOutputStream with a CipherOutputStream constructed with the FileOutputStream and your Cipher initialized to 'encrypt' mode.
4) Loop reading a buffer of data from the FileOutputStream and write it to the CipherOutputStream until you reach the EOF of the FileInputStream.
5) Close the CipherOutputStream (NOT NOT NOT the FileOutputStream).
6) Close the FileInputStream.
To decrypt one uses the same basic approach in reverse.
P.S. There is no point in trying to print out the encrypted file since it contains binary data and not characters.
Edited by: sabre150 on May 6, 2008 4:07 PM