import java.io.*;
import java.security.*;
import javax.crypto.*;
public class Des{
	public static void main(String args[])
	{	
		// DES獲取一個可信任的數據源
  		SecureRandom sr = new SecureRandom();
  		
		try{
				//生成一個keyGenerator對象
				KeyGenerator kg=KeyGenerator.getInstance("DES");
				kg.init(sr);
				//生成密鑰
				SecretKey k=kg.generateKey();
				//store k in file key.dat
				FileOutputStream f=new FileOutputStream("key.dat");
				ObjectOutputStream b=new ObjectOutputStream(f);
				b.writeObject(k);
				//打印密鑰
				byte rawKeyData[] = k.getEncoded();
				for(int i=0;i<rawKeyData.length;i++)
				System.out.print(rawKeyData[i]);
			}
		catch ( NoSuchAlgorithmException er1)
		{
			System.out.print(er1.toString());
		}
		catch(FileNotFoundException er2)
		{
				System.out.print(er2.toString());
		}
		catch(IOException er3)
		{
			System.out.print(er3.toString());	
		}
	}
}