package sit;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class CarHack {

    public static String calculateSalt(String ownid, String id, String n, String hashToFind) throws NoSuchAlgorithmException {

        MessageDigest md = MessageDigest.getInstance("SHA-256");
        String firstPart = ownid + id + n;

        for (int i = 1; i < 10000000; i++) {
            String toCheck = firstPart.concat(String.valueOf(i));

            md.update(toCheck.getBytes());
            byte byteData[] = md.digest();

            StringBuffer sb = new StringBuffer();
            for (int j = 0; j < byteData.length; j++) {
                sb.append(Integer.toString((byteData[j] & 0xff) + 0x100, 16).substring(1));
            }

            if (sb.toString().equals(hashToFind)) {
                System.out.println("Salt = " + i);
                return sb.toString();
            }

            if (i % 1000 == 0) {
                System.out.println(i);
            }

        }

        throw new RuntimeException("Salt not found");
    }


    private static void calculateNewHash(String ownid, String id, String n, String salt) throws NoSuchAlgorithmException {

        MessageDigest md = MessageDigest.getInstance("SHA-256");
        String rawData = ownid + id + n + salt;

        md.update(rawData.getBytes());
        byte byteData[] = md.digest();

        StringBuffer sb = new StringBuffer();
        for (int j = 0; j < byteData.length; j++) {
            sb.append(Integer.toString((byteData[j] & 0xff) + 0x100, 16).substring(1));
        }

        System.out.println("New Hash: " + sb.toString());

    }

    public static void main(String[] args) throws NoSuchAlgorithmException {
        //calculateNewHash bekommt die Werte aus der Aufgabenstellung
        //calculateSalt bekommt die Werte aus dem JavaScript Quellcode der Seite
        calculateNewHash("19d64efd69","door", "4887", calculateSalt("40d120326a", "door", "565", "5e4ca2a4d9d3b94994859ac72dbb97b4d73698c5ff2c3d020a4f89f65cb707e7"));
    }
}