DesUtil.java 6.13 KB
package com.ectrip.cyt.utils;

import java.security.Key;
import java.security.SecureRandom;
import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * DES加密和解密工具,可以对字符串进行加密和解密操作 。
 *
 * @author hezhihong
 */
public class DesUtil {
    /**
     * 加密工具
     */
    private static Cipher encryptCipher = null;

    /**
     * 解密工具
     */
    private static Cipher decryptCipher = null;

    private static final String ENCRYPT_KEY = "12345678";//8位密钥
    private static final String DES = "DES";

    /**
     * 将byte数组转换为表示16进制值的字符串, 如:byte[]{8,18}转换为:0813, 和public static byte[]
     * hexStr2ByteArr(String strIn) 互为可逆的转换过程
     *
     * @param arrB 需要转换的byte数组
     * @return 转换后的字符串
     * @throws Exception 本方法不处理任何异常,所有异常全部抛出
     */
    public static String byteArr2HexStr(byte[] arrB) throws Exception {
        int iLen = arrB.length;
        // 每个byte用两个字符才能表示,所以字符串的长度是数组长度的两倍
        StringBuffer sb = new StringBuffer(iLen * 2);
        for (int i = 0; i < iLen; i++) {
            int intTmp = arrB[i];
            // 把负数转换为正数
            while (intTmp < 0) {
                intTmp = intTmp + 256;
            }
            // 小于0F的数需要在前面补0
            if (intTmp < 16) {
                sb.append("0");
            }
            sb.append(Integer.toString(intTmp, 16));
        }
        return sb.toString();
    }

    /**
     * 将表示16进制值的字符串转换为byte数组, 和public static String byteArr2HexStr(byte[] arrB)
     * 互为可逆的转换过程
     *
     * @param strIn 需要转换的字符串
     * @return 转换后的byte数组
     * @throws Exception 本方法不处理任何异常,所有异常全部抛出
     */
    public static byte[] hexStr2ByteArr(String strIn) throws Exception {
        byte[] arrB = strIn.getBytes();
        int iLen = arrB.length;

        // 两个字符表示一个字节,所以字节数组长度是字符串长度除以2
        byte[] arrOut = new byte[iLen / 2];
        for (int i = 0; i < iLen; i = i + 2) {
            String strTmp = new String(arrB, i, 2);
            arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
        }
        return arrOut;
    }


    /**
     * 解密字节数组
     *
     * @param arrB 需解密的字节数组
     * @throws Exception
     */
    public static byte[] decrypt(byte[] arrB, String setkey) throws Exception {
        Security.addProvider(new com.sun.crypto.provider.SunJCE());
        Key key = getKey(setkey.getBytes());
        decryptCipher = Cipher.getInstance("DES");
//        decryptCipher = Cipher.getInstance("DES/ECB/ZeroBytePadding");
        decryptCipher.init(Cipher.DECRYPT_MODE, key);
        return decryptCipher.doFinal(arrB);
    }

    /**
     * 解密字符串
     *
     * @param strIn 需解密的字符串
     * @return 解密后的字符串
     * @throws Exception
     */
    public static String decrypt(String strIn, String setkey) throws Exception {
        return new String(decrypt(hexStr2ByteArr(strIn), setkey));
    }

    /**
     * 从指定字符串生成密钥,密钥所需的字节数组长度为8位 不足8位时后面补0,超出8位只取前8位
     *
     * @param arrBTmp 构成该字符串的字节数组
     * @return 生成的密钥
     * @throws java.lang.Exception
     */
    private static Key getKey(byte[] arrBTmp) throws Exception {
        // 创建一个空的8位字节数组(默认值为0)
        byte[] arrB = new byte[8];

        // 将原始字节数组转换为8位
        for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
            arrB[i] = arrBTmp[i];
        }
        // 生成密钥
        Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");

        return key;
    }

    /**
     *   * <对字符串进行Des加密,将字符串转化为字节数组解密>
     * <p>
     */

    public static byte[] desCrypto(byte[] datasource, String password) {
        try {
            SecureRandom random = new SecureRandom();
            DESKeySpec desKey = new DESKeySpec(password.getBytes());
            //创建一个密匙工厂,然后用它把DESKeySpec转换成
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey securekey = keyFactory.generateSecret(desKey);
            //Cipher对象实际完成加密操作
            Cipher cipher = Cipher.getInstance("DES");
//            Cipher cipher = Cipher.getInstance("DES/ECB/ZeroBytePadding");
            //用密匙初始化Cipher对象
            cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
            //现在,获取数据并加密
            //正式执行加密操作
            return cipher.doFinal(datasource);
        } catch (Throwable e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     *   * <将加密的密文字节数组转化为明文字节数组>
     * <p>
     */

    public static byte[] decrypt1(byte[] src, String password) throws Exception {

        // DES算法要求有一个可信任的随机数源
        SecureRandom random = new SecureRandom();
        // 创建一个DESKeySpec对象
        DESKeySpec desKey = new DESKeySpec(password.getBytes());
        // 创建一个密匙工厂
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        // 将DESKeySpec对象转换成SecretKey对象
        SecretKey securekey = keyFactory.generateSecret(desKey);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance("DES");
//        Cipher cipher = Cipher.getInstance("DES/ECB/ZeroBytePadding");
        // 用密匙初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, random);
        // 真正开始解密操作
        return cipher.doFinal(src);
    }

}