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package assignmentfour;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

/**
 * @author Shane Nolan
 * Assignment:
 * This program is carrying out what is called a dictionary attack to crack passwords.
 */
public class AssignmentFour {

    /**
     * @param args the command line arguments
     */
    final static String ENCRYPTION_TYPE = "MD5";
    public static void main(String[] args) throws IOException {
        List<User> users = new ArrayList<>();
        List<String> words = Files.readAllLines(Paths.get("dictionary.txt"));
        Connection connection = null;
        Statement statement = null;

        try {
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/sd3assignment4", "root", "");
            statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery("SELECT * FROM useraccounts");

            while (resultSet.next()) {
                users.add(new User(resultSet.getObject(1).toString(),
                        resultSet.getObject(2).toString()));
            }
        }
        catch (SQLException sqlex) {
            System.out.println("Comms error " + sqlex);
        }
        finally {
            try {
                statement.close();
                connection.close();
            } catch (SQLException sqlex) {
                System.out.println("Error cleaning up " + sqlex);
            }
        }

        Thread t1 = new Thread(() -> {
            users.forEach((u) -> {
                words.stream().filter((word) ->
                (hashPassword(ENCRYPTION_TYPE, word).equals(u.getPassword()))).forEachOrdered((word) -> {
                    System.out.println("Password for " + u.getUser() + " is " + word);
                });
            });
        });
        t1.start();
    }

    private static String hashPassword(String algorithm, String password) {
        StringBuilder sb = new StringBuilder();
        try {
            MessageDigest messaged = MessageDigest.getInstance(algorithm);
            messaged.update(password.getBytes());
            byte[] mdArray = messaged.digest();
            sb = new StringBuilder(mdArray.length * 2);
            for (byte b : mdArray) {
                int v = b & 0xff;
                if (v < 16) {
                    sb.append('0');
                }
                sb.append(Integer.toHexString(v));
            }
        }
        catch (NoSuchAlgorithmException nsae) {
            System.out.println(nsae);
        }
        return sb.toString();
    }

}

public class User {

    private String user;
    private String password;

    public User(String user, String password){
        this.user = user;
        this.password = password;
    }

    /**
     * @return the user
     */
    public String getUser() {
        return user;
    }

    /**
     * @param user the user to set
     */
    public void setUser(String user) {
        this.user = user;
    }

    /**
     * @return the password
     */
    public String getPassword() {
        return password;
    }

    /**
     * @param password the password to set
     */
    public void setPassword(String password) {
        this.password = password;
    }
}