fm9y9fJk

1import java.io.IOException;
2import java.nio.charset.StandardCharsets;
3import java.security.InvalidKeyException;
4import java.util.ArrayList;
5
6import javax.crypto.BadPaddingException;
7import javax.crypto.Cipher;
8import javax.crypto.IllegalBlockSizeException;
9import javax.crypto.SecretKey;
10import javax.crypto.SecretKeyFactory;
11import javax.crypto.spec.DESKeySpec;
12
13import sun.misc.BASE64Decoder;
14import sun.misc.BASE64Encoder;
15
16
17public class Cryptography {
18
19    public static String DES_ENCRYPTION_KEY;
20    public static String INPUT;
21
22    private static final String CRYPTOGRAPHY_ALGO_DES = "DES";
23    private static Cipher cipher = null;
24    private static DESKeySpec keySpec = null;
25    private static SecretKeyFactory keyFactory = null;
26
27    public static String encrypt(String inputString, String commonKey)
28            throws InvalidKeyException, IllegalBlockSizeException,
29            BadPaddingException {
30
31        String encryptedValue = null;
32        SecretKey key = getSecretKey(commonKey);
33        cipher.init(Cipher.ENCRYPT_MODE, key);
34
35        byte[] inputBytes = compare(inputString);
36
37        byte[] outputBytes = cipher.doFinal(inputBytes);
38        encryptedValue = new BASE64Encoder().encode(outputBytes);
39        return encryptedValue;
40    }
41
42    public static String decrypt(String encryptedString, String commonKey)
43            throws InvalidKeyException, IllegalBlockSizeException,
44            BadPaddingException, IOException {
45
46        String decryptedValue = "";
47// When Base64Encoded strings are passed in URLs, '+' character gets converted to space and so we need to reconvert the space to '+' and since encoded string cannot have space in it so we are completely safe.
48        encryptedString = encryptedString.replace(' ', '+');
49        SecretKey key = getSecretKey(commonKey);
50        cipher.init(Cipher.DECRYPT_MODE, key);
51
52        byte[] recoveredBytes = cipher.doFinal(new BASE64Decoder().decodeBuffer(encryptedString));
53
54        int[] out = new int[recoveredBytes.length];
55
56        String s = "";
57
58        for (int i = 0; i < recoveredBytes.length; i++) {
59
60            out[i] = recoveredBytes[i] & 0xFF;
61            s += Integer.toBinaryString(out[i]);
62
63        }
64
65        decryptedValue = new String(s);
66        return decryptedValue;
67    }
68
69    private static SecretKey getSecretKey(String secretPassword) {
70
71        SecretKey key = null;
72        try {
73            cipher = Cipher.getInstance(CRYPTOGRAPHY_ALGO_DES);
74
75            byte[] desKeyData = compare(secretPassword);
76
77            keySpec = new DESKeySpec(desKeyData);
78
79            keyFactory = SecretKeyFactory.getInstance(CRYPTOGRAPHY_ALGO_DES);
80            key = keyFactory.generateSecret(keySpec);
81
82        } catch (Exception e) {
83            e.printStackTrace();
84            System.out.println("Error in generating the secret Key");
85        }
86        return key;
87    }
88
89    public static void main(String args[]) {
90
91        try{
92
93            INPUT = "0000101111010101111101111101101110010000010011011011100111010010";
94            DES_ENCRYPTION_KEY = "1111101011001011101100110110111001110010000011100001001110011010";
95
96            String encrypted = Cryptography.encrypt(INPUT, DES_ENCRYPTION_KEY);
97            System.out.println("encrypted: " + encrypted);
98            String decrypted = Cryptography.decrypt(encrypted, DES_ENCRYPTION_KEY);
99            System.out.println("decrypted: " + decrypted);
100
101        }
102
103        catch(Exception e){
104
105        }
106    }
107
108
109    public static byte[] compare(String value) {
110
111        try {
112
113            ArrayList<String> str = new ArrayList<String>();
114            ArrayList<Byte> inputBytes = new ArrayList<Byte>();
115
116            int countS = 0;
117            int countE = 8;
118            int i = 0;
119
120
121            while (true) {
122
123                try {
124
125                    str.add(value.substring(countS, countE));
126
127                    //System.out.println(str.get(i));
128
129                    inputBytes.add((byte) Integer.parseInt(str.get(i), 2));
130
131                    //System.out.println(i + " " + inputBytes.get(i));
132
133                    countS += 8;
134                    countE += 8;
135
136                    i++;
137
138                } catch (Exception e2) {
139
140                    countE--;
141
142                    if(countE <= countS){
143                        break;
144                    }
145
146                }
147
148            }
149
150            byte[] array = new byte[inputBytes.size()];
151
152            for (int j=0; j < array.length; j++)
153            {
154                array[j] = inputBytes.get(j);
155            }
156            System.out.println("");
157            return array;
158
159    }
160
161        catch (Exception e1){
162
163            e1.printStackTrace();
164            return null;
165
166        }
167
168    }
169
170}