DES加密算法

 1 package com.tem1.util;
 2 
 3 import java.security.InvalidKeyException;  
 4 import java.security.NoSuchAlgorithmException;  
 5 import java.security.Security;  
 6   
 7 
 8 import javax.crypto.BadPaddingException;  
 9 import javax.crypto.Cipher;  
10 import javax.crypto.IllegalBlockSizeException;  
11 import javax.crypto.KeyGenerator;  
12 import javax.crypto.NoSuchPaddingException;  
13 import javax.crypto.SecretKey;  
14 
15 import com.sun.crypto.provider.SunJCE;
16   
17 public class EncrypDES {  
18       
19     //KeyGenerator 提供对称密钥生成器的功能，支持各种算法  如：DES  DESede(3DES)  AES
20     private KeyGenerator keygen;  
21     //SecretKey 负责保存对称密钥  
22     private SecretKey deskey;  
23     //Cipher负责完成加密或解密工作  
24     private Cipher c;  
25     //该字节数组负责保存加密的结果  
26     private byte[] cipherByte;  
27       
28     public EncrypDES() throws NoSuchAlgorithmException, NoSuchPaddingException{  
29         Security.addProvider(new SunJCE());  
30         //实例化支持DES算法的密钥生成器(算法名称命名需按规定，否则抛出异常)  
31        // keygen = KeyGenerator.getInstance("DESede");  
32         keygen = KeyGenerator.getInstance("DES");  
33         //生成密钥  
34         deskey = keygen.generateKey();  
35         System.out.println("Key  :"+deskey);
36         //生成Cipher对象,指定其支持的DES算法  
37         c = Cipher.getInstance("DES");  
38     }  
39       
40     /** 
41      * 对字符串加密 
42      *  
43      * @param str 
44      * @return 
45      * @throws InvalidKeyException 
46      * @throws IllegalBlockSizeException 
47      * @throws BadPaddingException 
48      */  
49     public byte[] Encrytor(String str) throws InvalidKeyException,  
50             IllegalBlockSizeException, BadPaddingException {  
51         // 根据密钥，对Cipher对象进行初始化，ENCRYPT_MODE表示加密模式  
52         c.init(Cipher.ENCRYPT_MODE, deskey);  
53       
54         byte[] src = str.getBytes();  
55         // 加密，结果保存进cipherByte  
56         cipherByte = c.doFinal(src);  
57         return cipherByte;  
58     }  
59   
60     /** 
61      * 对字符串解密 
62      *  
63      * @param buff 
64      * @return 
65      * @throws InvalidKeyException 
66      * @throws IllegalBlockSizeException 
67      * @throws BadPaddingException 
68      */  
69     public byte[] Decryptor(byte[] buff) throws InvalidKeyException,  
70             IllegalBlockSizeException, BadPaddingException {  
71         // 根据密钥，对Cipher对象进行初始化，DECRYPT_MODE表示加密模式  
72         c.init(Cipher.DECRYPT_MODE, deskey);  
73         cipherByte = c.doFinal(buff);  
74         return cipherByte;  
75     }  
76   
77     /** 
78      * @param args 
79      * @throws NoSuchPaddingException  
80      * @throws NoSuchAlgorithmException  
81      * @throws BadPaddingException  
82      * @throws IllegalBlockSizeException  
83      * @throws InvalidKeyException   
84      */  
85     public static void main(String[] args) throws Exception {  
86         EncrypDES de1 = new EncrypDES();  
87         String msg ="明天七点出发";  
88         byte[] encontent = de1.Encrytor(msg);  
89         byte[] decontent = de1.Decryptor(encontent);  
90         System.out.println("明文是:" + msg);  
91         System.out.println("加密后:" + new String(encontent));  
92         System.out.println("解密后:" + new String(decontent));  
93     }  
94   
95 }