We have a Hash function with at 80 bit output that is collis

We have a Hash function with at 80 bit output that is collision resistant and second pre-image resistant. If you were an attacker and you were trying to perform a brute force attack on the Hash function will you target its collision resistance or its second pre-image and why? Can any techniques help you on your brute force attack?

Solution

I would try brute force attack on collision resistance because theoretically it will take 2^80 computations for second pre-image attack which is infeasible to do whereas for second preimage attack, I\'ll require only 2^40 computations which is feasible in a few hours.