[Evans] Now the answer is the third one--
that it makes it about 4000 times harder.
So to compute a dictionary that would be effective against all the different salts,
the attacker really needs to pre-compute that dictionary for all the different salt values
to be able to look for passwords that match.
So salting adds a lot of value for very little cost.
We just need some extra bits that don't need to be kept secret
that are stored in our password file.
