Java实现DES加密解密（DES填充模式DES/CBC/PKCS5Padding）计算字符串的md5值

Java实现DES加密解密（DES填充模式DES/CBC/PKCS5Padding）计算字符串的md5值

本文介绍了DES使用DES/CBC/PKCS5Padding填充模式进行加解密的过程，同时包含计算字符串的md5值

直接上代码：

1、使用bc计算字符串的md5值(bcprov-jdk15on)

	/**
     * 使用指定编码，获取指定字符串的md5值
     *
     * @param data     字符串
     * @param encoding 编码
     * @return md5值
     */
    public static String md5Encode(String data, String encoding) {
        try {
            Digest digest = new MD5Digest();
            digest.update(data.getBytes(encoding), 0, data.getBytes(encoding).length);
            byte[] md5Bytes = new byte[digest.getDigestSize()];
            digest.doFinal(md5Bytes, 0);
            return Hex.encodeHexString(md5Bytes);
        } catch (UnsupportedEncodingException e) {
            logger.error("异常",e);
            return null;
        }
    }

2、使用DES进行加解密操作

2.1、使用DES进行加密

    /**
     * 使用指定的key对字符串加密
     *
     * @param data 待加密字符串
     * @param key 密钥
     * @return 加密后的数据
     */
    public static String encrypt(String data, String key) {
        byte[] bt = new byte[0];
        String encodeData = "";
        try {
            bt = encrypt(data.getBytes(CHARSET_UTF8), key.getBytes(CHARSET_UTF8));
            //字节转化为16进制字符串
            encodeData = byteToHexString(bt);
        } catch (Exception e) {
            logger.error("异常",e);
        }
        return encodeData;
    }
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        SecureRandom sr = new SecureRandom();

        DESKeySpec dks = new DESKeySpec(key);

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        Cipher cipher = Cipher.getInstance(PKCS_5_PADDING);
        cipher.init(Cipher.ENCRYPT_MODE, securekey, new IvParameterSpec(dks.getKey()));
        return cipher.doFinal(data);
    }
    /**
     *
     * 将byte数组转换成16进制字符串
     *
     * @param bytes byte数组
     * @return 16进制字符串
     */
    public static String byteToHexString(byte[] bytes) {
        StringBuffer sb = new StringBuffer(bytes.length);
        String sTemp;
        for (int i = 0; i < bytes.length; i++) {
            sTemp = Integer.toHexString(0xFF & bytes[i]);
            if (sTemp.length() < 2) {
                sb.append(0);
            }
            sb.append(sTemp.toUpperCase());
        }
        return sb.toString();
    }

2.2、使用DES进行解密

    /**
     *
     * @param data
     * @param key
     * @return
     */
    public static String decrypt(String data, String key) {
        String decryptString = "";
        try {
            byte[] bt = decrypt(hexStringToBytes(data), key.getBytes(CHARSET_UTF8));
            decryptString = new String(bt, CHARSET_UTF8);
        } catch (Exception e) {
            logger.error("异常",e);
        }
        return decryptString;
    }
    /**
     * 解密
     * @param data byte数组
     * @param key 加密key
     * @return 解密后的byte数组
     * @throws Exception 异常
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        SecureRandom sr = new SecureRandom();
        DESKeySpec dks = new DESKeySpec(key);

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance(PKCS_5_PADDING);
        // 用密钥初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, new IvParameterSpec(dks.getKey()));

        return cipher.doFinal(data);
    }
    /**
     * 将16进制字符串转换为byte[]
     *
     * @param str 待转字符串
     * @return 转后的byte数组
     */
    public static byte[] hexStringToBytes(String str) {
        if (str == null || str.trim().equals("")) {
            return new byte[0];
        }
        byte[] bytes = new byte[str.length() / 2];
        for (int i = 0; i < str.length() / 2; i++) {
            String subStr = str.substring(i * 2, i * 2 + 2);
            bytes[i] = (byte) Integer.parseInt(subStr, 16);
        }
        return bytes;
    }

3、验证

执行main方法，验证

    /**
     * 加密方式 DES
     */
    private final static String DES = "DES";

    /**
     * 填充模式 DES/CBC/PKCS5Padding
     */
    private final static String PKCS_5_PADDING = "DES/CBC/PKCS5Padding";

    /**
     * 字符编码 UTF-8
     */
    static final String CHARSET_UTF8 = "UTF-8";

    public static void main(String[] args) {
        String data = "good good study,day day up";
        String key = "P0e5FGMl8VNukjGWqIf4LnmEdUnMyyGvsbzEt4gWelIrpSQDX7EX4kncpJUPbjDf";

        String md5String = md5Encode(data,CHARSET_UTF8);
        System.out.println("md5:" + md5String);

        String desString = encrypt(data,key);
        System.out.println("DES:" + desString);

        String decodeString = decrypt(desString,key);
        System.out.println(decodeString);

    }

控制台输出如下：

md5:d656aead64940dbf9ec40a070de756ed
DES:7AB164197D530D0C41BFDB321F41E53F7A47946CA8DC4954A0A5589944999428
good good study,day day up

4、需要应用的包

本示例程序使用maven进行构建，需要引用相关的jar包依赖，如下：

        <dependency>
            <groupId>org.bouncycastlegroupId>
            <artifactId>bcprov-jdk15onartifactId>
            <version>1.60version>
        dependency>
        <dependency>
            <groupId>commons-langgroupId>
            <artifactId>commons-langartifactId>
            <version>2.6version>
        dependency>
        <dependency>
            <groupId>commons-codecgroupId>
            <artifactId>commons-codecartifactId>
            <version>1.13version>
        dependency>
        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-apiartifactId>
            <version>1.7.30version>
        dependency>