M-Factor Authentication

Mfactor.java

import java.util.*;
import java.security.*;
import java.lang.*;
class Rand{
	//We generate a pattern to be used by the client applications 
	//We make an assumption that the application uses a four digita pin and thus we give it an initial value of 1234
	//intialize the original password
	final static String originalPassword="8217";
	static String enteredPassword;
	public static void main(String[] args){
	    	// the array of valid numbers
			int[] numbers = {1,2,3,4};// intialize this however you want


			Random rand = new Random();

			//initialize the lenght of 
			int numLength = 4;


			StringBuilder output = new StringBuilder();

			for (int i = 0; i < numLength; i++) {
			    // use a random index to choose a number from array
			    int thisNum = rand.nextInt(numbers.length);
			    // append random number from array to output 
			    output.append(thisNum);
			}

			System.out.println(output.toString());

			String pattern=output.toString();
			//Prompt the user to enter the password based on the given pattern
			Scanner reader = new Scanner(System.in);  // Reading from System.in
			System.out.println("The pattern for your current login is:\n "+ pattern);
			System.out.println("Enter the password that matches the pattern : ");
			enteredPassword = reader.nextLine();

			System.out.println("The entered passsword is " +enteredPassword+ " and original is "+originalPassword);

			//invoke function to check password 
			//matchPassword(pattern,enteredPassword,originalPassword)
			matchPassword(pattern,enteredPassword);

	
	}
	public static void matchPassword(String pattern, String enteredPassword){

		//Extract the numbers from string and form the new password based on the pattern
		StringBuilder sessionPass = new StringBuilder();

		for(int i=0; i<pattern.length();i++){
			
			int index=Character.getNumericValue(pattern.charAt(i));
			//System.out.println(index);
			char passChar=originalPassword.charAt(index);
			
			sessionPass.append(passChar);
		}

		System.out.println("The session pass is "+sessionPass+ " and the entered pass is "+enteredPassword);
		String sessionPassStr=sessionPass.toString();
		//compare if the two passwords match and then authenticate the user
		if(sessionPassStr.equals(enteredPassword)){
			System.out.println("The user has been successfully authenticated");
		}
		else{
			System.out.println("Access denied");
		}
		

		
	}
}