Question

1. (60%) Assume an 8-letter password from the 95 printable ASCII characters is used in a computer system. a. If passwords are chosen by the users, what is the total password population? What is the probability of an adversary guessing a password correctly? b. If passwords are generated automatically by a pseudorandom number generator, what is the total password population? What is the probability of an adversary guessing a password correctly?

Answer 1

Explanation:

a. There are 8 characters in the password, and 95 possibilities for each character. The number of possible combinations is:

95⁸

b. The probability of a password being guessed correctly is:

1 / 95⁸

c. If a number generator is used, there are 10 possibilities for each character. The number of possible combinations is:

10⁸

d. The probability of a password being guessed correctly is:

1 / 10⁸