Encrypt

package servletservice;
import java.security.*;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
/**
* 字符串工具集合
* @author Liudong
*/
public class Encrypt {

    private static final String PASSWORD_CRYPT_KEY = "c_jDlog_";
    private final static String DES = "DES";

    /**
     * 加密
     * @param src 数据源
     * @param key 密钥，长度必须是8的倍数
     * @return 返回加密后的数据
     * @throws Exception
     */
    public static byte[] encrypt(byte[] src, byte[] key) throws Exception {
//DES算法要求有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
// 从原始密匙数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
// 创建一个密匙工厂，然后用它把DESKeySpec转换成
// 一个SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = 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, securekey, sr);
// 现在，获取数据并加密
// 正式执行加密操作
        return cipher.doFinal(src);
    }

    /**
     * 解密
     * @param src 数据源
     * @param key 密钥，长度必须是8的倍数
     * @return 返回解密后的原始数据
     * @throws Exception
     */
    public static byte[] decrypt(byte[] src, byte[] key) throws Exception {
// DES算法要求有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
// 从原始密匙数据创建一个DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
// 创建一个密匙工厂，然后用它把DESKeySpec对象转换成
// 一个SecretKey对象
        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(DES);
// 用密匙初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
// 现在，获取数据并解密
// 正式执行解密操作
        return cipher.doFinal(src);
    }

    /**
     * 密码解密
     * @param data
     * @return
     * @throws Exception
     */
    public final static String decrypt(String data) {
        try {
            return new String(decrypt(hex2byte(data.getBytes()),PASSWORD_CRYPT_KEY.getBytes()));
            //return new String(decrypt(hex2byte(data.getBytes()),PASSWORD_CRYPT_KEY.getBytes()),"GB2312");
        } catch (Exception e) {
        }
        return null;
    }

    /**
     * 密码加密
     * @param password
     * @return
     * @throws Exception
     */
    public final static String encrypt(String password) {
        try {
            String strc=password;
            strc=new String(strc.getBytes("GB2312"));
            return byte2hex(encrypt(password.getBytes(),PASSWORD_CRYPT_KEY.getBytes()));
            //return byte2hex(encrypt(strc.getBytes(),PASSWORD_CRYPT_KEY.getBytes()));
        } catch (Exception e) {
        }
        return null;
    }

    public static String byte2hex(byte[] b) {

                 String hs = "";

                 String stmp = "";

                 for (int n = 0; n < b.length; n++) {

                     stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));

                     if (stmp.length() == 1)

                         hs = hs + "0" + stmp;

                     else

                         hs = hs + stmp;

                 }

                 return hs.toUpperCase();

            }



           public static 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;
           }
}