Question: Traditional password entry scheme are susceptible to "shoulder surfing" in which an attacker watches an unsuspecting user enter their password or pin number and uses it later to gain access to the account. One way to combat this problem is with a randomized challenge-response system. In these system the user enters different information every time based on a secret in response to a randomly generated challenge Consider the following scheme in which the password consists of a five-digit pin number (00000 to 99999). Each digit is assigned a random number that is 1, 2, or 3. The user enter the random numbers that correspond to their PIN instead of their actual PIN number.
For example, consider an actual PIN number of 12345. To authenticate the user would be presented with a screen such as:
PIN: 0 1 2 3 4 5 6 7 8 9
NUM: 3 2 3 1 1 3 2 2 1 3
The user would enter 23113 instead of 12345. This doesn't divulge the password even if an attacker intercepts the entry because 23113 could correspond to other PIN numbers, such as 69400 or 70439. The next time the user logs in, a different sequence of random numbers would be generated, such as:
PIN: 0 1 2 3 4 5 6 7 8 9
NUM: 1 1 2 3 1 2 2 3 3 3
Write a program to simulate the authentication process. Store an actual PIN number in your program. The program should use an array to assign random number to the digits from 0 to 9. Output the random digits to the screen, input the response correctly matches the PIN number.