Java DES 加密/解密详解编程语言

import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.security.Security; 
import java.security.spec.AlgorithmParameterSpec; 
 
import javax.crypto.Cipher; 
import javax.crypto.CipherInputStream; 
import javax.crypto.CipherOutputStream; 
import javax.crypto.KeyGenerator; 
import javax.crypto.SecretKey; 
import javax.crypto.spec.IvParameterSpec; 
 
public class Main { 
 
    static Cipher ce; 
    static Cipher cd; 
 
    public static void main(String args[]) throws Exception { 
 
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); 
 
        SecretKey skey = KeyGenerator.getInstance("DES").generateKey(); 
 
        byte[] initializationVector = new byte[]{0x10, 0x10, 0x01, 0x04, 0x01, 0x01, 0x01, 0x02}; 
 
        AlgorithmParameterSpec algParameters = new IvParameterSpec(initializationVector); 
        ce = Cipher.getInstance("DES/CBC/PKCS5Padding"); 
        cd = Cipher.getInstance("DES/CBC/PKCS5Padding"); 
 
        ce.init(Cipher.ENCRYPT_MODE, skey, algParameters); 
        cd.init(Cipher.DECRYPT_MODE, skey, algParameters); 
 
        FileInputStream is = new FileInputStream("C:/Users/nikos7/Desktop/output.txt"); 
        FileOutputStream os = new FileOutputStream("C:/Users/nikos7/Desktop/output2.txt"); 
        int dataSize = is.available(); 
 
        byte[] inbytes = new byte[dataSize]; 
        is.read(inbytes); 
 
        String str2 = new String(inbytes); 
        System.out.println("Input file content/n" + str2 + "/n"); 
 
        write_encode(inbytes, os); 
 
        os.flush(); 
        is.close(); 
        os.close(); 
 
        System.out.println("Ecrypted Content to output2.txt/n"); 
 
        is = new FileInputStream("C:/Users/nikos7/Desktop/output2.txt"); 
 
        byte[] decBytes = new byte[dataSize]; 
 
        read_decode(decBytes, is); 
 
        is.close(); 
 
        String str = new String(decBytes); 
 
        System.out.println("Decrypted file contents:/n" + str); 
 
    } 
 
    public static void write_encode(byte[] bytes, OutputStream output) throws Exception { 
        CipherOutputStream cOutputStream = new CipherOutputStream(output, ce); 
        cOutputStream.write(bytes, 0, bytes.length); 
        cOutputStream.close(); 
    } 
 
    public static void read_decode(byte[] bytes, InputStream input) throws Exception { 
        CipherInputStream cInputStream = new CipherInputStream(input, cd); 
        int position = 0, i; 
 
        while ((i = cInputStream.read()) != -1) { 
            bytes[position] = (byte) i; 
            position++; 
        } 
    } 
}