备忘DES简单加密与解密

package com.ego.util;

import java.io.IOException;
import java.security.SecureRandom;

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

public class DESUtils {

private final static String DES = "DES";
public static void main(String[] args) throws Exception {
    String data = "{'uid':'admin','pwd':'21232f297a57a5a743894a0e4a801fc3'}";
    String key = "20161108";
    String afterEn=encrypt(data, key);
    System.out.println(afterEn);
    System.out.println(decrypt(afterEn, key));

}
 
/**
 * Description 根据键值进行加密
 * @param data 
 * @param key  加密键byte数组
 * @return
 * @throws Exception
 */
public static String encrypt(String data, String key) throws Exception {
    byte[] bt = encrypt(data.getBytes(), key.getBytes());
    String strs=byte2hex(bt);
    return strs;
}

/**
 * Description 根据键值进行解密
 * @param data
 * @param key  加密键byte数组
 * @return
 * @throws IOException
 * @throws Exception
 */
public static String decrypt(String data, String key)throws Exception{
    if (data == null)
        return null;
    	byte[] buf = hex2byte(data.getBytes());
		byte[] bt = decrypt(buf,key.getBytes());
		return new String(bt);
}

/**
 * Description 根据键值进行加密
 * @param data
 * @param key  加密键byte数组
 * @return
 * @throws Exception
 */
private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
    // 生成一个可信任的随机数源
    SecureRandom sr = new SecureRandom();

    // 从原始密钥数据创建DESKeySpec对象
    DESKeySpec dks = new DESKeySpec(key);

    // 创建一个密钥工厂，然后用它把DESKeySpec转换成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);

    // 用密钥初始化Cipher对象
    cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

    return cipher.doFinal(data);
}
 
 
/**
 * Description 根据键值进行解密
 * @param data
 * @param key  加密键byte数组
 * @return
 * @throws Exception
 */
private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
    // 生成一个可信任的随机数源
    SecureRandom sr = new SecureRandom();

    // 从原始密钥数据创建DESKeySpec对象
    DESKeySpec dks = new DESKeySpec(key);

    // 创建一个密钥工厂，然后用它把DESKeySpec转换成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);

    // 用密钥初始化Cipher对象
    cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

    return cipher.doFinal(data);
}
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;
}

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();
}

}