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Question 4: Traditional password entry schemes 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 systems 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 enters the random numbers that correspond to their PIN instead of their actual PIN numbers. 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 69440 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 5-digit PIN number in your program (make one up, and store it as a constant). The program should use an array to assign random numbers to the digits from 0 to 9. Output the random digits to the screen, input the response from the user, and output whether or not the user's response correctly matches the PIN number. Assuming that the actual PIN number is 12345, your program should interact with the user exactly as it shows in the following examples (2 different executions of the program): Please enter your PIN according to the following mapping: PIN: 012 3 4 5 6 7 8 9 NUM: 32 3 1132 213 23113 Your PIN is correct Please enter your PIN according to the following mapping: PIN: 012 3 4 5 6 7 8 9 NUM: 112 312 2 333 23113 Your PIN is not correct Note: Think how to break down your implementation to functions. Question 5: Write a program that reads a person's name in the following format: first name, then middle name or initial, and then last name. The program then outputs the name in the following format: Last_Name, First_Name Middle_Initial. For example, the input Mary Average User should produce the output: User, Mary A. The input Mary A. User should also produce the output: User, Mary A. Note that your program should work the same and place a period after the middle initial even if the input did not contain a period. Hint: You may want to use three string variables rather than one large string variable for the input. You may find it easier to not use getline. Question 6: Write a program that reads in a line of text and outputs the line with all the digits in all integer numbers replaced with 'x'. Please enter a line of text: My userID is john17 and my 4 digit pin is 1234 which is secret My userID is john17 and my x digit pin is XXXX which is secret Notes: 1. If a digits is part of a word, then the digit is not changed to an 'x'. For example, john17 is NOT changed to johnxx. 2. You may assume that the text entered by the user will contain only letters (upper case or lower case), digits and spaces. 3. Think how to break down your implementation to functions