Question

A password hash function is applied 12 times to secure a password. If it takes 21 minutes to brute force one application of the hash with the available resources, how long will it take to brute force the password if the available resources are quadrupled.?

a. 21 minutes
b. 63 minutes
c. 210 minutes
d. none of the above.

Answer 1

b. 63 minutes

Explanation:

Given;

number of times the hash function is applied = 12

time taken to brute force one application, = 21 minutes

Apply proportion, bearing in mind that 4 available resources should take less time;

1 available resource ------- 21 minutes

4 available resources ------ x

Thus, x = 21 minutes / 4

When applied 12 times, the time should be
`(21 \ minutes)/(4) \ * \ 12 \ = 63 \ minutes \\\\`

Therefore, the correct option is B, 63 minutes