I'm reading this book about Computer Security to better prepare me for my role, however, this question is just not clicking to me. I've figured out half of it, but cannot figure out this last part. If someone can show me how, that would be great.
The question:
Assume that passwords in a system are limited to the use of 95 printable ASCII characters and that all passwords are 10 characters in length. Assume the system is not using any salt values.
a. How many different passwords are possible? 95^10 possible passwords
b. Assume a password cracker with an encryption rate of 6.4 million encryptions per second. How long will it take to test all possible passwords? 296,653 years (based on my calculations)
Suppose that there are only 4 users in the system described in part (I) of the question, and each user has a different salt value (stored as plain text in the password file).
c. If the password cracker above is used, how long will it take to test all possible passwords?
I cannot figure out question C. The added possibility of 4 users and different salt values is really throwing me off. If I could figure out the different combinations, the time needed to test all passwords would be cake to calculate. If someone can show me how to figure this out, that would be great!