DES加密、解密例子

    关于DES加密、解密之类在JE中也有挺多的例子，也不确定这算不算原创。欢迎学习、感谢拍砖指导！

/**
 * Created by IntelliJ IDEA.
 * User: liangj
 */
public class DesKeyManager {
    public final static String DEFAULT_KEY = "PKCS5Padding";
    protected final static String DES = "DES";
    protected static String key;

    protected String getKey() {
        return key;
    }

    public static void setKey(String key) {
        DesKeyManager.key = key;
    }
}

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

/**
 * Created by IntelliJ IDEA.
 * User: liangj
 */
public class DesEncrypt extends DesKeyManager {
    private static DesEncrypt _instance = null;

    private DesEncrypt() {

    }

    public static DesEncrypt getInstance() {
        if (_instance == null) {
            _instance = new DesEncrypt();
        }
        return _instance;
    }

    /**
     * 加密
     * @param key 密匙，其长度必须是8的倍数
     * @param src 数据源
     * @return 返回加密后的数据
     * @throws Exception
     */
    private byte[] encrypt(byte[] key, byte[] src) throws Exception {
        //DES算法需要有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        //从原始密匙数据（key）创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
        //创建一个密匙工厂
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        //使用密匙工厂把DESKeySpec转换成一个SecretKey对象
        SecretKey sk = keyFactory.generateSecret(dks);
        //Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance(DES);
        //用密匙初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, sk, sr);

        //现在开始对数据源src进行加密
        return cipher.doFinal(src);
    }

    /**
     * 二进制转换成十六进制
     * @param b
     * @return
     */
    public String byte2hex(byte[] b) {
        String hs = "";
        String stmp;

        for (byte aB : b) {
            stmp = (Integer.toHexString(aB & 0XFF));
            if (stmp.length() == 1) {
                hs = hs + "0" + stmp;
            } else {
                hs = hs + stmp;
            }
        }

        return hs.toLowerCase();
    }

    /**
     * 加密方法
     * @param src 数据源
     * @return
     */
    public String encrypt(String src) {
        try {
            return byte2hex(encrypt(getKey().getBytes(), src.getBytes()));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public String encrypt(byte[] src) {
        try {
            return byte2hex(encrypt(getKey().getBytes(), src));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

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

/**
 * Created by IntelliJ IDEA.
 * User: liangj
 */
public class DesDecrypt extends DesKeyManager {
    private static DesDecrypt _instance = null;

    private DesDecrypt() {

    }

    public static DesDecrypt getInstance() {
        if (_instance == null) {
            _instance = new DesDecrypt();
        }
        return _instance;
    }

    /**
     * 解密
     * @param key 密匙，其长度必须是8的倍数
     * @param src 经过DES加密的数据源
     * @return 返回解密后的数据
     * @throws Exception
     */
    private byte[] decrypt(byte[] key, byte[] src) throws Exception {
        //需要创建一个可信任的随机数源对象
        SecureRandom sr = new SecureRandom();
        //从原始密匙数据（src）创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
        //创建一个密匙工厂
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        //使用密匙工厂把DESKeySpec转换成SecretKey对象
        SecretKey sk = keyFactory.generateSecret(dks);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance(DES);
        //用密匙初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, sk, sr);

        //现在开始对数据源src进行解密
        return cipher.doFinal(src);
    }

    /**
     * 十六进制转换成二进制
     * @param b
     * @return
     */
    public byte[] hex2byte(byte[] b) {
        if ((b.length % 2) != 0) {
            throw new IllegalArgumentException("长度不是偶数");
        }
        byte[] b2 = new byte[b.length / 2];
        for (int n = 0; n < b.length; n += 2) {
            String item = new String(b, n, 2);
            b2[n / 2] = (byte) Integer.parseInt(item, 16);
        }
        return b2;
    }

    /**
     * 解密方法
     * @param src 数据源
     * @return
     */
    public byte[] decrypt(String src) {
        try {
            return decrypt(getKey().getBytes(), hex2byte(src.getBytes()));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public byte[] decrypt(byte[] src) {
        try {
            return decrypt(getKey().getBytes(), hex2byte(src));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }    
}