Joash's School Assignment

Joash.java

import java.io.*;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Scanner;


class InvalidPasswordException extends Exception {

    int passwordConditionViolated = 0;

    public InvalidPasswordException(int conditionViolated)
    {
        super("Invalid Password: ");
        passwordConditionViolated = conditionViolated;
    }

    public String printMessage()
    {
        // Call constructor of parent Exception
        // according to the condition violated
        switch (passwordConditionViolated) {

            // Password length should be
            // between 8 to 15 characters
            case 1:
                return ("Password length should be between 8 to 15 characters");

            // Password should not contain any space
            case 2:
                return ("Password should not contain any space");

            // Password should contain// at least one digit(0-9)
            case 3:
                return ("Password should contain at least one digit(0-9)");

            // Password should contain at least
            // one special character ( @, #, %, &, !, $ )
            case 4:
                return ("Password should contain at least one special character");

            // Password should contain at least
            // one uppercase letter(A-Z)
            case 5:
                return ("Password should contain at least one uppercase letter(A-Z)");

            // Password should contain at least
            // one lowercase letter(a-z)
            case 6:
                return ("Password should contain at least one lowercase letter(a-z)");
        }

        return ("");
    }
}


public class Assignment1 {

    public static void isValid(String password) throws InvalidPasswordException
    {

        // for checking if password length
        // is between 8 and 15
        if (!((password.length() >= 8)
                && (password.length() <= 16))) {
            throw new InvalidPasswordException(1);
        }

        // to check space
        if (password.contains(" ")) {
            throw new InvalidPasswordException(2);
        }
        if (true) {
            int count = 0;

            // check digits from 0 to 9
            for (int i = 0; i <= 9; i++) {

                // to convert int to string
                String str1 = Integer.toString(i);

                if (password.contains(str1)) {
                    count = 1;
                }
            }
            if (count == 0) {
                throw new InvalidPasswordException(3);
            }
        }

        // for special characters
        if (!(password.contains("@") || password.contains("#")
                || password.contains("!") || password.contains("~")
                || password.contains("$") || password.contains("%")
                || password.contains("^") || password.contains("&")
                || password.contains("*") || password.contains("(")
                || password.contains(")") || password.contains("-")
                || password.contains("+") || password.contains("/")
                || password.contains(":") || password.contains(".")
                || password.contains(", ") || password.contains("<")
                || password.contains(">") || password.contains("?")
                || password.contains("|"))) {
            throw new InvalidPasswordException(4);
        }

        if (true) {
            int count = 0;

            // checking capital letters
            for (int i = 65; i <= 90; i++) {

                // type casting
                char c = (char)i;

                String str1 = Character.toString(c);
                if (password.contains(str1)) {
                    count = 1;
                }
            }
            if (count == 0) {
                throw new InvalidPasswordException(5);
            }
        }

        if (true) {
            int count = 0;

            // checking small letters
            for (int i = 90; i <= 122; i++) {

                // type casting
                char c = (char)i;
                String str1 = Character.toString(c);

                if (password.contains(str1)) {
                    count = 1;
                }
            }
            if (count == 0) {
                throw new InvalidPasswordException(6);
            }
        }

        // The password is valid
    }

    public static String getMd5(String input) {
        try {

            // Static getInstance method is called with hashing MD5
            MessageDigest md = MessageDigest.getInstance("MD5");

            // digest() method is called to calculate message digest
            //  of an input digest() return array of byte
            byte[] messageDigest = md.digest(input.getBytes());

            // Convert byte array into signum representation
            BigInteger no = new BigInteger(1, messageDigest);

            // Convert message digest into hex value
            String hashtext = no.toString(16);
            while (hashtext.length() < 32) {
                hashtext = "0" + hashtext;
            }
            return hashtext;
        }

        // For specifying wrong message digest algorithms
        catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    public static void createTxt() throws IOException {
        // create salt.txt
        File slt = new File("salt.txt");
        slt.createNewFile(); // if file already exists will do nothing
        //    FileOutputStream oFile = new FileOutputStream(myFile, false);
        // fileCreate();
        //create shadow.txt
        File shadow = new File("shadow.txt");
        shadow.createNewFile();
        File fs = new File("file.store.txt");
        fs.createNewFile();
    }

    public static void createUser()throws IOException, InvalidPasswordException {

        File slt = new File("salt.txt");
        File shadow = new File("shadow.txt");

        Scanner myObj = new Scanner(System.in);
        Scanner salt = new Scanner(slt);
        Scanner shad = new Scanner(shadow);

        FileWriter saltfw = new FileWriter("salt.txt", true);
        BufferedWriter saltbw = new BufferedWriter(saltfw);

        FileWriter shadfw = new FileWriter("shadow.txt", true);
        BufferedWriter shadbw = new BufferedWriter(shadfw);

        System.out.print("Enter Username: ");

        String userName = myObj.nextLine();

        while (salt.hasNextLine()) {
            String[] data = salt.nextLine().split(":");
            // System.out.println(salt.nextLine());
            if (data[0].equals(userName)) {
                System.out.println("User already exist");
                System.exit(0);
            }

        }

        Console console = System.console();

        int pwCheck = 0;
        String pw1 = "";
        String pw2 = "";
        while (pwCheck < 4){
            System.out.print("Enter Password: ");
            pw1 = myObj.nextLine();
            // console.printf("Enter Password: ");
            // char [] password1 = console.readPassword();
            // pw1 = new String(password1);


            try {
                isValid(pw1);
                System.out.print("Confirm Password: ");
                pw2 = myObj.nextLine();
                //console.printf("Confirm Password: ");
                // char [] password2 = console.readPassword();
                // pw2 = new String(password2);
                if (pw1.equals(pw2)) {
                    //   System.out.print("GTFO.\n");
                    break;
                }
                else {
                    System.out.print("Password does not match.\n");
                    pwCheck++;
                    //   System.out.println(pwCheck);
                }

            }
            catch (InvalidPasswordException e) {
                System.out.print(e.getMessage());
                System.out.println(e.printMessage());
                pwCheck++;
                //           System.out.println(pwCheck);

            }
            if (pwCheck==4){
                System.exit(0);}

        }

        System.out.print("Enter clearance level: ");
        String CL = myObj.nextLine();
        if (!CL.equals("0") & !CL.equals("1") & !CL.equals("2") & !CL.equals("3")){
            System.out.println("Invalid clearance level.");
            System.exit(0);
        }


        String NUM = "0123456789";
        StringBuilder sb = new StringBuilder();

        for (int i=0; i<8; i++){
            int index = (int)(NUM.length() * Math.random());

            sb.append(NUM.charAt(index));

        }

        //  System.out.println(pw1+sb);
        //  System.out.println(getMd5(pw1+sb));

        saltbw.append(userName + ":"+ sb +"\n");
        shadbw.append(userName + ":"+getMd5(pw1+sb)+":"+CL+"\n");
        System.out.println("Successfully wrote to the file.");
        //bw.append(userName + ":"+ pw1 + ":" +CL+"\n");
        saltbw.flush();
        saltbw.close();
        shadbw.flush();
        shadbw.close();

        //   bw.append(userName + "\n");
        //  bw.flush();
        //   bw.close();
        //    System.out.println("Successfully wrote to the file.");
    }

    public static String[] Login() throws IOException {
        File slt = new File("salt.txt");
        File shadow = new File("shadow.txt");

        Scanner myObj = new Scanner(System.in);
        Scanner salt = new Scanner(slt);
        Scanner shad = new Scanner(shadow);

        System.out.print("Enter Username: ");
        String UsrNm = myObj.nextLine();
        String pwdSalt= "";
        String shadpwdHash = "";
        String shadCL = "";


        boolean userFound = false;
        while (salt.hasNextLine()) {
            String[] data = salt.nextLine().split(":");
            // System.out.println(salt.nextLine());
            if (data[0].equals(UsrNm)) {
                // System.out.println("fk");
                //  System.out.println(data[1]);
                userFound = true;
                pwdSalt= data[1];
                break;
            }
        }
        while (shad.hasNextLine()) {
            String[] data = shad.nextLine().split(":");
            // System.out.println(salt.nextLine());
            if (data[0].equals(UsrNm)) {
                // System.out.println("fk");
                //  System.out.println(data[1]);
                shadpwdHash= data[1];
                shadCL = data[2];
                break;
            }
        }

        if (!userFound ){
            System.out.println("Invalid Username");
            System.exit(0);
        }

        //Console console = System.console();
        //console.printf("Enter Password: ");
        //  char [] password1 = console.readPassword();
        //  pwd = new String(password1);
        System.out.print("Enter Password: ");
        String pwd = myObj.nextLine();
        String pwdHash = getMd5(pwd+pwdSalt);
        System.out.println(UsrNm + " found in salt.txt");
        System.out.println("salt retrieved: " + pwdSalt);
        System.out.println("hashing...");
        System.out.println("hash value: " + pwdHash);

        if(pwdHash.equals(shadpwdHash)) {
            System.out.println("Authentication for user "+ UsrNm + " complete.");
            System.out.println("The clearance for "+ UsrNm + " is "+ shadCL +"\n");
        }
        else{
            System.out.println("Incorrect Password.");
            System.exit(0);
        }


        //System.out.println(pwdSalt + "fk mi life");
        // loggedIn(UsrNm, shadCL);
        return new String[]{UsrNm,shadCL};
    }

//    public static String[] usrName(String Name, String clearance){
//        String usrName = Name;
//        String CL = clearance;
//        return new String[]{usrName, CL};
//    }


    public static int showMenuNGetOption(
        String username,
        String clearanceLevel,
        String filename
    ) throws IOException {
        Scanner scanner = new Scanner(System.in);
        File fileStore = new File("file.store.txt");
        Scanner sf = new Scanner(fileStore);
        FileWriter FWfileStore = new FileWriter("file.store.txt", true);
        BufferedWriter BWfileStore = new BufferedWriter(FWfileStore);

        String usrInput= "";

        while(!usrInput.equalsIgnoreCase("C") & !usrInput.equalsIgnoreCase("A")& !usrInput.equalsIgnoreCase("R")& !usrInput.equalsIgnoreCase("W")& !usrInput.equalsIgnoreCase("L")& !usrInput.equalsIgnoreCase("S")& !usrInput.equalsIgnoreCase("E") ) {
            System.out.println("Options: (C)reate, (A)ppend, (R)ead, (W)rite, (L)ist, (S)ave or (E)xit");
            usrInput = scanner.nextLine();

            if (usrInput.equalsIgnoreCase("C")) {
                System.out.println("Enter Filename: ");
                filename = scanner.nextLine();
                File usrFile = new File(filename);
                usrFile.createNewFile();
                System.out.println("File Created");
                showMenuNGetOption(username, clearanceLevel, filename);
            }
            else if (usrInput.equalsIgnoreCase("A")) {
                System.out.println("APPEND");
                break;
            }
            else if (usrInput.equalsIgnoreCase("R")) {
                System.out.println("READ");
                break;
            }
            else if (usrInput.equalsIgnoreCase("W")) {
                System.out.println("WRITE");
                break;
            }
            else if (usrInput.equalsIgnoreCase("L")) {
                // System.out.println("List ");
                String line;
                while (sf.hasNextLine()) {
                    System.out.println(sf.nextLine());
                }
                showMenuNGetOption(username, clearanceLevel, filename);
            }
            else if (usrInput.equalsIgnoreCase("S")) {
                BWfileStore.append(filename+":"+username+":"+clearanceLevel);
                BWfileStore.flush();
                BWfileStore.close();
                System.out.println("File Save");
                System.out.println(filename);
                showMenuNGetOption(username, clearanceLevel, filename);
            }
            else if (usrInput.equalsIgnoreCase("E")) {
                System.out.println("Shut down the FileSystem? (Y)es or (N)o ");
                String sd = scanner.nextLine();
                if (sd.equalsIgnoreCase("y")){
                    break;}
                else{
                    showMenuNGetOption(username, clearanceLevel, filename);
                }
            }
        }
        return 0;
    }

    public static void main(String[] args) throws IOException, InvalidPasswordException {
        createTxt();
//        createUser();

        String[] userCredentials = Login();
        String username = userCredentials[0];
        String clearanceLevel = userCredentials[1];

        showMenuNGetOption(username, clearanceLevel, "");
    }
}