Des对称加密

  1 package com.util;
  2 import java.io.IOException;
  3 import java.security.SecureRandom;
  4 
  5 import javax.crypto.Cipher;
  6 import javax.crypto.SecretKey;
  7 import javax.crypto.SecretKeyFactory;
  8 import javax.crypto.spec.DESKeySpec;
  9 
 10 import sun.misc.BASE64Decoder;
 11 import sun.misc.BASE64Encoder;
 12 public class DesUtil {
 13     private final static String DES = "DES";
 14     private final static String ENCODE = "UTF-8";
 15     private final static String defaultKey = "nextdactive";
 16 
 17     /**
 18      * 使用 默认key 加密
 19      * @param data 待加密数据
 20      * @return
 21      * @throws Exception
 22      */
 23     public static String encrypt(String data) {
 24         byte[] bt = null;
 25         try {
 26             bt = encrypt(data.getBytes(ENCODE), defaultKey.getBytes(ENCODE));
 27         } catch (Exception e) {
 28             e.printStackTrace();
 29         }
 30         String strs = new BASE64Encoder().encode(bt);
 31         return strs;
 32     }
 33 
 34     /**
 35      * 使用 默认key 解密
 36      * @param data 待解密数据
 37      * @return
 38      * @throws IOException
 39      * @throws Exception
 40      */
 41     public static String decrypt(String data) {
 42         if (data == null)
 43             return null;
 44         BASE64Decoder decoder = new BASE64Decoder();
 45         byte[] buf;
 46         byte[] bt;
 47         String string = null;
 48         try {
 49             buf = decoder.decodeBuffer(data);
 50             bt = decrypt(buf, defaultKey.getBytes(ENCODE));
 51             string = new String(bt, ENCODE);
 52         } catch (Exception e) {
 53             e.printStackTrace();
 54         }
 55         return string;
 56     }
 57 
 58     /**
 59      * Description 根据键值进行加密
 60      * @param data 待加密数据
 61      * @param key 密钥
 62      * @return
 63      * @throws Exception
 64      */
 65     public static String encrypt(String data, String key) throws Exception {
 66         byte[] bt = encrypt(data.getBytes(ENCODE), key.getBytes(ENCODE));
 67         String strs = new BASE64Encoder().encode(bt);
 68         return strs;
 69     }
 70 
 71     /**
 72      * 根据键值进行解密
 73      * @param data 待解密数据
 74      * @param key    密钥
 75      * @return
 76      * @throws IOException
 77      * @throws Exception
 78      */
 79     public static String decrypt(String data, String key) throws IOException,
 80             Exception {
 81         if (data == null)
 82             return null;
 83         BASE64Decoder decoder = new BASE64Decoder();
 84         byte[] buf = decoder.decodeBuffer(data);
 85         byte[] bt = decrypt(buf, key.getBytes(ENCODE));
 86         return new String(bt, ENCODE);
 87     }
 88 
 89     /**
 90      * Description 根据键值进行加密
 91      * 
 92      * @param data
 93      * @param key
 94      *            加密键byte数组
 95      * @return
 96      * @throws Exception
 97      */
 98     private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
 99         // 生成一个可信任的随机数源
100         SecureRandom sr = new SecureRandom();
101 
102         // 从原始密钥数据创建DESKeySpec对象
103         DESKeySpec dks = new DESKeySpec(key);
104 
105         // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
106         SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
107         SecretKey securekey = keyFactory.generateSecret(dks);
108 
109         // Cipher对象实际完成加密操作
110         Cipher cipher = Cipher.getInstance(DES);
111 
112         // 用密钥初始化Cipher对象
113         cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
114 
115         return cipher.doFinal(data);
116     }
117 
118     /**
119      * Description 根据键值进行解密
120      * 
121      * @param data
122      * @param key 加密键byte数组
123      * @return
124      * @throws Exception
125      */
126     private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
127         // 生成一个可信任的随机数源
128         SecureRandom sr = new SecureRandom();
129 
130         // 从原始密钥数据创建DESKeySpec对象
131         DESKeySpec dks = new DESKeySpec(key);
132 
133         // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
134         SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
135         SecretKey securekey = keyFactory.generateSecret(dks);
136 
137         // Cipher对象实际完成解密操作
138         Cipher cipher = Cipher.getInstance(DES);
139 
140         // 用密钥初始化Cipher对象
141         cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
142 
143         return cipher.doFinal(data);
144     }
145     
146     public static void main(String[] args){
147         String data = "hello world";
148         String key ="qfdrrdwf";
149         System.out.println("加密前:"+data);
150         try {
151             System.out.println("加密后:"+encrypt(data, key));
152             System.out.println("解密后:"+decrypt(encrypt(data, key), key));
153         } catch (Exception e) {
154             e.printStackTrace();
155         }
156     }
157 }