SM01sbH9

1/*
2 * DES encrypting/decrypting for text data
3 */
4 
5 
6import java.security.*;
7import javax.crypto.*;
8 
9public class SimpleDESCryptoProvider {
10    
11    public static final String seed = "AM6ROFFBABFAKILLEMALL";
12 
13    public static String decrypt(String src)
14    {
15 
16       try{
17        javax.crypto.spec.SecretKeySpec
18             key = new  javax.crypto.spec.SecretKeySpec(getRawKey(), "DES");
19        Cipher ecipher = Cipher.getInstance("DES");
20        ecipher.init(Cipher.DECRYPT_MODE, key);
21    
22        byte[] utf8 = toByte(src);
23 
24        // Descrypt
25        byte[] dec= ecipher.doFinal(utf8);
26 
27        return new String( dec  );
28        }
29        catch(Exception exc )
30        {
31           try{
32               exc.printStackTrace();
33            }catch(Exception exc2){}
34 
35        }
36       return src;
37 
38    }
39 
40     public static String encrypt(String src)
41    {
42       try{
43        javax.crypto.spec.SecretKeySpec
44             key = new  javax.crypto.spec.SecretKeySpec(getRawKey(), "DES");
45        Cipher ecipher = Cipher.getInstance("DES");
46        ecipher.init(Cipher.ENCRYPT_MODE, key);
47        
48        byte[] utf8 = src.getBytes("UTF8");
49 
50        // Encrypt
51        byte[] enc = ecipher.doFinal(utf8);
52 
53        return toHex(enc);
54        }
55        catch(Exception exc )
56        {
57           try{
58              exc.printStackTrace();
59            }catch(Exception exc2){}
60 
61        }
62       return src;
63    }
64 
65     private static byte[] getRawKey() throws Exception {
66     KeyGenerator kgen = KeyGenerator.getInstance("DES");
67  SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
68  sr.setSeed(seed.getBytes());
69     kgen.init(56, sr);
70     SecretKey skey = kgen.generateKey();
71     byte[] raw = skey.getEncoded();
72     return raw;
73 }
74 
75    // эти методы используются для конвертации байтов в ASCII символы
76 
77     public static String toHex(String txt) {
78  return toHex(txt.getBytes());
79 }
80 public static String fromHex(String hex) {
81  return new String(toByte(hex));
82 }
83 
84 public static byte[] toByte(String hexString) {
85  int len = hexString.length()/2;
86  byte[] result = new byte[len];
87  for (int i = 0; i < len; i++)
88   result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
89  return result;
90 }
91 
92 public static String toHex(byte[] buf) {
93  if (buf == null)
94   return "";
95  StringBuffer result = new StringBuffer(2*buf.length);
96  for (int i = 0; i < buf.length; i++) {
97   appendHex(result, buf[i]);
98  }
99  return result.toString();
100 }
101 private final static String HEX = "0123456789ABCDEF";
102 private static void appendHex(StringBuffer sb, byte b) {
103  sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
104 }
105}
106Использование класса может выглядеть следующим образом:
107
108String s = "Привет.";
109        String d = SimpleDESCryptoProvider.encrypt(s);
110        System.out.println(d);
111        s = SimpleDESCryptoProvider.decrypt(d);
112        System.out.println(s);