BB6zG9gV

1import javax.swing.*;
2import java.security.SecureRandom;
3import javax.crypto.Cipher;
4import javax.crypto.KeyGenerator;
5import javax.crypto.SecretKey;
6import javax.crypto.spec.SecretKeySpec;
7import java.util.Random ;
8
9public class DESEncryptionExample {
10    byte[] skey = new byte[1000];
11    String skeyString;
12    static byte[] raw;
13    String inputMessage,encryptedData,decryptedMessage;
14
15    public DESEncryptionExample() {
16        try {
17            generateSymmetricKey();
18
19            inputMessage=JOptionPane.showInputDialog(null,"Enter message to encrypt");
20            byte[] ibyte = inputMessage.getBytes();
21            byte[] ebyte=encrypt(raw, ibyte);
22            String encryptedData = new String(ebyte);
23            System.out.println("Encrypted message "+encryptedData);
24            JOptionPane.showMessageDialog(null,"Encrypted Data "+"\n"+encryptedData);
25
26            byte[] dbyte= decrypt(raw,ebyte);
27            String decryptedMessage = new String(dbyte);
28            System.out.println("Decrypted message "+decryptedMessage);
29
30            JOptionPane.showMessageDialog(null,"Decrypted Data "+"\n"+decryptedMessage);
31        }
32        catch(Exception e) {
33            System.out.println(e);
34        }
35
36    }
37    void generateSymmetricKey() {
38        try {
39            Random r = new Random();
40            int num = r.nextInt(10000);
41            String knum = String.valueOf(num);
42            byte[] knumb = knum.getBytes();
43            skey=getRawKey(knumb);
44            skeyString = new String(skey);
45            System.out.println("DES Symmetric key = "+skeyString);
46        }
47        catch(Exception e) {
48            System.out.println(e);
49        }
50    }
51    private static byte[] getRawKey(byte[] seed) throws Exception {
52        KeyGenerator kgen = KeyGenerator.getInstance("DES");
53        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
54        sr.setSeed(seed);
55        kgen.init(56, sr);
56        SecretKey skey = kgen.generateKey();
57        raw = skey.getEncoded();
58        return raw;
59    }
60    private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
61        SecretKeySpec skeySpec = new SecretKeySpec(raw, "DES");
62        Cipher cipher = Cipher.getInstance("DES");
63        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
64        byte[] encrypted = cipher.doFinal(clear);
65        return encrypted;
66    }
67
68    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
69        SecretKeySpec skeySpec = new SecretKeySpec(raw, "DES");
70        Cipher cipher = Cipher.getInstance("DES");
71        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
72        byte[] decrypted = cipher.doFinal(encrypted);
73        return decrypted;
74    }
75    public static void main(String args[]) {
76        DESEncryptionExample des = new DESEncryptionExample();
77    }
78}