【java工具類】DES加密

DES全稱爲Data Encryption Standard，即數據加密標準，是一種使用密鑰加密的塊算法，1976年被美國聯邦政府的國家標準局確定爲聯邦資料處理標準（FIPS），隨後在國際上廣泛流傳開來。

百度百科中解釋：
http://baike.baidu.com/link?url=yciLi4U1xPAeMhJcgDQzqE-b-U3QCxE_4hVH-ISdb6OPpVMl5WReOY-Tx2Vi-OPaGjfPCkYEPYPhn1RiUgxfia

源代碼

import java.io.IOException;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class DesUtil {

    private final static String DES = "DES";

    public static void main(String[] args) throws Exception {
        String data = "kaixuanFor3lingDAO";//加密內容
        String key = "d!d11dderew!#@#@r111";
        System.err.println(encrypt(data, key));
        System.err.println(decrypt(encrypt(data, key), key));
    }

    /**
     * Description 根據鍵值進行加密
     * @param data 
     * @param key  加密鍵byte數組
     * @return
     * @throws Exception
     */
    public static String encrypt(String data, String key) throws Exception {
        byte[] bt = encrypt(data.getBytes(), key.getBytes());
        String strs = new BASE64Encoder().encode(bt);
        return strs;
    }

    /**
     * Description 根據鍵值進行解密
     * @param data
     * @param key  加密鍵byte數組
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data, String key) throws IOException,
            Exception {
        if (data == null)
            return null;
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] buf = decoder.decodeBuffer(data);
        byte[] bt = decrypt(buf,key.getBytes());
        return new String(bt);
    }

    /**
     * Description 根據鍵值進行加密
     * @param data
     * @param key  加密鍵byte數組
     * @return
     * @throws Exception
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();

        // 從原始密鑰數據創建DESKeySpec對象
        DESKeySpec dks = new DESKeySpec(key);

        // 創建一個密鑰工廠，然後用它把DESKeySpec轉換成SecretKey對象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher對象實際完成加密操作
        Cipher cipher = Cipher.getInstance(DES);

        // 用密鑰初始化Cipher對象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }

    /**
     * Description 根據鍵值進行解密
     * @param data
     * @param key  加密鍵byte數組
     * @return
     * @throws Exception
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();

        // 從原始密鑰數據創建DESKeySpec對象
        DESKeySpec dks = new DESKeySpec(key);

        // 創建一個密鑰工廠，然後用它把DESKeySpec轉換成SecretKey對象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher對象實際完成解密操作
        Cipher cipher = Cipher.getInstance(DES);

        // 用密鑰初始化Cipher對象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }
}