加密-DES

下面是使用jdk提供的加密类库进行DES加密样例

 1 public class TestDES {
 2 
 3   //SecretKey 负责保存对称密钥
 4   private SecretKey deskey;
 5   //Cipher负责完成加密或解密工作
 6   private Cipher c;
 7 
 8   public TestDES() throws NoSuchAlgorithmException, NoSuchPaddingException {
 9     Security.addProvider(new com.sun.crypto.provider.SunJCE());
10     //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)
11     KeyGenerator keygen = KeyGenerator.getInstance("DES");
12     //生成密钥
13     deskey = keygen.generateKey();
14     //生成Cipher对象,指定其支持的DES算法
15     c = Cipher.getInstance("DES");
16   }
17 
18 
19   public byte[] encrypt(String str) throws InvalidKeyException,
20           IllegalBlockSizeException, BadPaddingException {
21     // 根据密钥，对Cipher对象进行初始化，ENCRYPT_MODE表示加密模式
22     c.init(Cipher.ENCRYPT_MODE, deskey);
23     byte[] src = str.getBytes();
24     // 加密，结果保存进cipherByte
25     byte[] cipherByte = c.doFinal(src);
26     return cipherByte;
27   }
28   public byte[] encrypt(byte[] src) throws InvalidKeyException,
29           IllegalBlockSizeException, BadPaddingException {
30     // 根据密钥，对Cipher对象进行初始化，ENCRYPT_MODE表示加密模式
31     c.init(Cipher.ENCRYPT_MODE, deskey);
32     // 加密，结果保存进cipherByte
33     byte[] cipherByte = c.doFinal(src);
34     return cipherByte;
35   }
36   public byte[] decrypt(byte[] buff) throws InvalidKeyException,
37           IllegalBlockSizeException, BadPaddingException {
38     // 根据密钥，对Cipher对象进行初始化，DECRYPT_MODE表示加密模式
39     c.init(Cipher.DECRYPT_MODE, deskey);
40     byte[] cipherByte = c.doFinal(buff);
41     return cipherByte;
42   }
43 
44   public static void main(String[] args) throws Exception {
45     TestDES de1 = new TestDES();
46     byte[] bytes = new byte[]{'z', 'h', 'a', 'n', 'g', '\2', '\2', '\3'};
47     byte[] encontent = de1.encrypt(bytes);
48     byte[] decontent = de1.decrypt(encontent);
49     System.out.println("明文是:" + new String(decontent));
50   }
51 }

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