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1import java.io.FileReader;
2import java.io.Console; 
3import java.util.Scanner; 
4import java.security.MessageDigest; 
5import java.security.SecureRandom;
6import java.security.NoSuchAlgorithmException;
7import java.security.spec.InvalidKeySpecException;
8import javax.crypto.SecretKeyFactory;
9import javax.crypto.spec.PBEKeySpec;
10import javax.crypto.SecretKey;
11import javax.xml.bind.annotation.adapters.HexBinaryAdapter; 
12import com.opencsv.CSVReader; 
13
14public class LabSecurity {
15    private static final char[] characters = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
16            'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
17
18    private static final int HASH_ITERS = 10000;
19    private static final int SALT_LENGTH = 32;
20    private static final int HASH_LENGTH = 512;
21
22    private boolean found;
23    private String match;
24
25    private MessageDigest md5; 
26    private byte[] byteRepresentation;
27    private byte[] hash;
28    private String strHexHash;
29    private HexBinaryAdapter hba; 
30
31    /**
32     * Constructor for objects of class LabSecurity
33     */
34    public LabSecurity() {
35        try {
36            md5 = MessageDigest.getInstance("MD5");
37            hba = new HexBinaryAdapter();
38        } catch (NoSuchAlgorithmException nsae) {
39        }
40    }
41
42    public void tryMD5() {
43        try {
44            String str;
45            do {
46                System.out.println("Input a string to generate its MD5 hash (press enter to quit)");
47                Scanner terminalInput = new Scanner(System.in);
48                str = terminalInput.nextLine();
49                if (!str.equals("")) {
50                    System.out.println(encodeMD5(str));
51                }
52            } while (!str.equals(""));
53        } catch (Exception e) {
54        }
55
56    }
57
58    private String encodeMD5(final String input) throws Exception {
59        byteRepresentation = input.getBytes("UTF-8");
60        hash = md5.digest(byteRepresentation);
61        strHexHash = hba.marshal(hash);
62        return strHexHash;
63    }
64
65    public void bruteForce(final String input) {
66        try {
67            CSVReader reader = new CSVReader(new FileReader(input));
68            String[] nextLine;
69            reader.readNext(); 
70            System.out.println("Brute force");
71            while ((nextLine = reader.readNext()) != null) {
72                System.out.print(nextLine[0] + " " + nextLine[1] + " ");
73                found = false;
74                String password = "not found";
75                if (found) {
76                    password = match;
77                }
78                System.out.println(password);
79            }
80        } catch (Exception e) {
81        }
82    }
83
84    /**
85     * Recursively explore all passwords shorter or equal to parameter <length>,
86     * made up of characters from the <characters> class variable
87     * to find the password which has the same MD5 hash as parameter <hash>.
88     * The <found> global variable needs to be initialised to false prior to calling the method.
89     * Results are stored in the <found> and <match> global variables.
90     * <p>
91     * bruteForceRecursive(10, 0, "", <hash>) will try passwords
92     * of 10 or fewer characters until it finds one that hashes to <hash> or
93     * all passwords have been tried unsuccessfully.
94     */
95    private void bruteForceRecursive(final int length, final int position, final String baseString, final String hash) throws Exception {
96        for (int i = 0; i < characters.length & !found; i++) {
97            String attempt = baseString + characters[i];
98            found = hash.equals(encodeMD5(attempt));
99            if (found) {
100                match = attempt;
101            } else {
102
103                if (position < length - 1) {
104                    bruteForceRecursive(length, position + 1, attempt, hash);
105                }
106            }
107        }
108    }
109
110    public String generateHash(String password) {
111        String result = "";
112        return result;
113    }
114
115    private byte[] hashPassword(final char[] password, final byte[] salt, final int iterations, final int keyLength) {
116
117        try {
118            SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA512");
119            PBEKeySpec spec = new PBEKeySpec(password, salt, iterations, keyLength);
120            SecretKey key = skf.generateSecret(spec);
121            byte[] res = key.getEncoded();
122            return res;
123        } catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
124            throw new RuntimeException(e);
125        }
126    }
127
128
129}