Java DES加密解密工具類

public class DESUtil {
    private byte[] desKey;

    //解密數據
    public static String decrypt(String message,String key) throws Exception {

        byte[] bytesrc =convertHexString(message);
        Cipher   cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
        IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));

        cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);

        byte[] retByte = cipher.doFinal(bytesrc);
        return new String(retByte);
    }

    public static byte[] encrypt(String message, String key)
            throws Exception {
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");

        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
        IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

        return cipher.doFinal(message.getBytes("UTF-8"));
    }

    public static byte[] convertHexString(String ss)
    {
        byte digest[] = new byte[ss.length() / 2];
        for(int i = 0; i < digest.length; i++)
        {
            String byteString = ss.substring(2 * i, 2 * i + 2);
            int byteValue = Integer.parseInt(byteString, 16);
            digest[i] = (byte)byteValue;
        }

        return digest;
    }


    public static void main(String[] args) throws Exception {
        String key = "12345678";
        String value="testtesttest";
        String jiami=java.net.URLEncoder.encode(value, "utf-8").toLowerCase();

        System.out.println("加密數據:"+jiami);
        String a=toHexString(encrypt(jiami, key)).toUpperCase();


        System.out.println("加密後的數據爲:"+a);

        String b=java.net.URLDecoder.decode(decrypt(a,key), "utf-8") ;
        System.out.println("解密後的數據:"+b);

    }


    public static String toHexString(byte b[]) {
        StringBuffer hexString = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            String plainText = Integer.toHexString(0xff & b[i]);
            if (plainText.length() < 2)
                plainText = "0" + plainText;
            hexString.append(plainText);
        }

        return hexString.toString();
    }

}</span>

運行main方法，可以得到：

<span style="font-size:14px;">加密數據:testtesttest
加密後的數據爲:6ED959688AEC719B9F3857C7966A817E
解密後的數據:testtesttest</span>

以上是Java的DES加密的工具類，其中的key值長度只能爲8位。