wLy3HdTW

1import javax.crypto.*;
2import javax.crypto.spec.DESKeySpec;
3import java.util.Arrays;
4
5public class TripleDES {
6
7    enum MODE {
8        ENCRYPT(0), DECRYPT(1);
9        int code;
10
11        MODE(int code) {
12            this.code = code;
13        }
14    }
15
16    public static byte[] encrypt(String plaintext, String rawkey) throws Exception {
17        return _trip(plaintext.getBytes(), rawkey.getBytes(), MODE.ENCRYPT);
18    }
19
20    public static String decrypt(byte[] encrypted, String rawkey) throws Exception {
21        String res = "";
22
23        for (byte b : _trip(encrypted, rawkey.getBytes(), MODE.DECRYPT))
24            res += String.format("%c", b);
25
26        return res;
27    }
28
29    private static SecretKey prepKey(byte[] key) throws Exception {
30        DESKeySpec dks = new DESKeySpec(key);
31        SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
32        return skf.generateSecret(dks);
33    }
34
35    private static byte[] _trip(byte[] input, byte[] key, MODE mode) throws Exception {
36        int process[][] = {
37                {Cipher.ENCRYPT_MODE, Cipher.DECRYPT_MODE, Cipher.ENCRYPT_MODE},  // encrypt
38                {Cipher.DECRYPT_MODE, Cipher.ENCRYPT_MODE, Cipher.DECRYPT_MODE}}; // decrypt
39        byte[] res = input;
40
41        for (int i = 0; i < 3; i++)
42            res = _digest(res, Arrays.copyOfRange(key, 0 * 8, (i + 1) * 8), process[mode.code][i]);
43
44        return res;
45    }
46
47    private static byte[] _digest(byte[] plain, byte[] key, int mode) throws Exception {
48        Cipher cipher = Cipher.getInstance("DES");
49        cipher.init(mode, prepKey(key));
50        return cipher.doFinal(plain);
51    }
52
53    public static void main(String[] args) {
54        String plaintext = "Did you hear about the restaurant on the moon?",
55                passphrase = "Good food, no atmosphere";
56        try {
57            byte[] encrypted = TripleDES.encrypt(plaintext, passphrase);
58            System.out.println(TripleDES.decrypt(encrypted, passphrase));
59
60        } catch (Exception e) {
61            e.printStackTrace();
62        }
63    }
64}