des_decrypt.java.bak

DESedeCBC实验

import java.io.*;
import javax.crypto.*;
import java.security.*;
import javax.crypto.spec.*;

public class DES_decrypt
{
	public static void main(String arg[])  throws Exception
	{
		
		System.out.println("Decrypt the \"ctext.dat\" to \"ptext2.dat\".");
		
         FileInputStream f=new FileInputStream("SEncCBC.dat");
         byte[] rand=new byte[8];
         f.read(rand);
         IvParameterSpec iv=new IvParameterSpec(rand);

        

	     FileInputStream f2=new FileInputStream("key1.dat");
	     ObjectInputStream ob=new ObjectInputStream(f2);
	     Key k=(Key)ob.readObject( );

  	    Cipher cp=Cipher.getInstance("DESede/CBC/PKCS5Padding");
        cp.init(Cipher.DECRYPT_MODE, k, iv);
        FileInputStream fin=new FileInputStream("ctext.dat");
		CipherInputStream cin=new CipherInputStream(fin, cp);
			
		FileOutputStream fout=new FileOutputStream("ptext2.dat");



			
			int b=0;
			while( (b=cin.read())!=-1)
			{
				fout.write(b);
				System.out.print((char)b);
			}
			System.out.println();
		
	}
}