hzmZV9XV

1import java.math.BigInteger;
2import java.util.*;
3import javax.crypto.Cipher;
4import javax.crypto.SecretKey;
5import javax.crypto.spec.SecretKeySpec;
6
7/**
8 *
9 * @author MAXIMUM13
10 */
11public class DESModel {
12
13    private static final Cipher CIPHER;
14    private static final int RADIX = 16;
15    private static final int N = 8;
16    private static final int IND0 = -128;
17    private static final int IND1 = 128;
18
19    static {
20        Cipher cipher = null;
21        try {
22            cipher = Cipher.getInstance("DES/ECB/NoPadding");
23        } catch (Exception exc) {
24        }
25        CIPHER = cipher;
26    }
27
28    public static void main(String[] args) throws Exception {
29        compute();
30    }
31
32    private static void compute() throws Exception {
33        String lastKey0Bytes = "37e1748602";
34        String lastKey1Bytes = "d9d4b016c2";
35
36        String openText0 = "European";
37        String cipherText0 = "99f7b96a3c8ad748";
38
39        String openText1 = "exercise";
40        String cipherText1 = "f8e84cb72ea2ef58";
41
42        String cipherText2 = "e1d785c6dcfb726c";
43
44        byte[] key0LastBytes = toBytes(lastKey0Bytes, RADIX);
45        byte[] key1LastBytes = toBytes(lastKey1Bytes, RADIX);
46
47        byte[] openText0Bytes = openText0.getBytes();
48        byte[] openText1Bytes = openText1.getBytes();
49
50        byte[] cipherText0Bytes = toBytes(cipherText0, RADIX);
51        byte[] cipherText1Bytes = toBytes(cipherText1, RADIX);
52        byte[] cipherText2Bytes = toBytes(cipherText2, RADIX);
53
54        byte[] key0Bytes = new byte[N];
55        int len = key0LastBytes.length;
56        System.arraycopy(key0LastBytes, 0, key0Bytes, N - len, len);
57
58        byte[] key1Bytes = new byte[N];
59        len = key1LastBytes.length;
60        System.arraycopy(key1LastBytes, 0, key1Bytes, N - len, len);
61
62        final Map<String, SecretKey> keysMap = new TreeMap<>();
63
64        for (int i = IND0; i < IND1; i++, i++) {
65            key1Bytes[0] = (byte) i;
66            System.out.println(i);
67            for (int j = IND0; j < IND1; j++, j++) {
68                key1Bytes[1] = (byte) j;
69                for (int k = IND0; k < IND1; k++, k++) {
70                    key1Bytes[2] = (byte) k;
71                    SecretKey secretKey = new SecretKeySpec(key1Bytes.clone(), "DES");
72
73                    byte[] cText0 = doFinal(Cipher.ENCRYPT_MODE, openText0Bytes, secretKey);
74                    String cText = new String(cText0);
75                    keysMap.put(cText, secretKey);
76                }
77            }
78        }
79
80        System.out.println();
81
82        int c = 0;
83        loop:
84        {
85            for (int i = IND0; i < IND1; i++, i++) {
86                key0Bytes[0] = (byte) i;
87                System.out.println(i);
88                for (int j = IND0; j < IND1; j++, j++) {
89                    key0Bytes[1] = (byte) j;
90                    for (int k = IND0; k < IND1; k++, k++) {
91                        key0Bytes[2] = (byte) k;
92                        SecretKey secretKey = new SecretKeySpec(key0Bytes.clone(), "DES");
93
94                        byte[] cText0 = doFinal(Cipher.DECRYPT_MODE, cipherText0Bytes, secretKey);
95                        String cText = new String(cText0);
96                        if (keysMap.containsKey(cText)) {
97                            c++;
98                            SecretKey key0 = secretKey;
99                            SecretKey key1 = keysMap.get(cText);
100                            boolean f = check(openText1Bytes, cipherText1Bytes, key0, key1);
101                            if (f) {
102                                byte[] openTextBytes = doFinal(Cipher.DECRYPT_MODE, cipherText2Bytes, key1, key0);
103                                String openText = new String(openTextBytes);
104
105                                System.out.println();
106                                System.out.println("map.size(): " + keysMap.size());
107                                System.out.println("keys: " + c);
108                                System.out.println("open text: " + openText);
109                                System.out.println("key0: " + Utils.toHexString(key0.getEncoded()));
110                                System.out.println("key1: " + Utils.toHexString(key1.getEncoded()));
111                                break loop;
112                            }
113                        }
114                    }
115                }
116            }
117        }
118    }
119
120    private static boolean check(byte[] openText, byte[] cipherText,
121            SecretKey key0, SecretKey key1) throws Exception {
122        return Arrays.equals(doFinal(Cipher.ENCRYPT_MODE, openText, key0, key1), cipherText);
123    }
124
125    private static byte[] doFinal(int mode, byte[] message,
126            SecretKey key0, SecretKey key1) throws Exception {
127        return doFinal(mode, doFinal(mode, message, key1), key0);
128    }
129
130    private static byte[] doFinal(int mode, byte[] message,
131            SecretKey key) throws Exception {
132        CIPHER.init(mode, key);
133        return CIPHER.doFinal(message);
134    }
135    
136    public static byte[] toBytes(String s, int radix) {
137        byte[] a0 = new BigInteger(s, radix).toByteArray();
138        int ind = a0.length > 0 && a0[0] == 0 ? 1 : 0;
139        byte[] a1 = new byte[a0.length - ind];
140        System.arraycopy(a0, ind, a1, 0, a1.length);
141        return a1;
142    }
143}