But I might add that 'brute force' hunting is not the way to go about this problem, like the other guy 'LBC' linear collider, its stupid to search 1-N, where N is 2**256, as that is counting all the atoms in the universe, many times over. It can't be done, unless you have an infinite time-frame to solve the problem,
Wasn't LBC created to solve the puzzle transactions? Just like BitCrack was? Up to this point it has been a relatively small search space, so not impossible to brute force.
Cracking an arbitrary, 100% random private key is a different matter, of course.
One advantage of focusing on puzzle transactions is that finding (and taking) those funds presents no moral dilemma. It's meant to be a reward.