Comment: Protocol questions

(See in situ)

In reply to comment: doggydogworld I appreciate (see in situ)

Protocol questions

Thanks for the pointers on the protocol issue. When I have time I'll try to go back and look more, but isn't the point of the 51% attack that the miner(s) who control 51% of the mining capacity (even if that's just one person) can generate the longest block chain and then, unless the bitcoin ptb roll back to a checkpoint, that becomes *by definition* the "official" block chain?

Also I think you're wrong about the possibility of nullified transactions being about the 51% attack vulnerability. A 51% attack wouldn't be an "accidental" nullification, it would be a malicious nullification. The accidental nullification can occur (correct me if I'm wrong) because the transaction might be on a branch that is superseded by a longer bitcoin chain. From the FAQ:

As a consequence of the block chain structure, there may at any time be many different sub-branches, and the possibility always exists of a transaction being over-written by the longest branch, if it has been recorded in a shorter one. The older a transaction is though, the lower its chances of being over-written, and the higher of becoming permanent. Although the block chain prevents one from spending more Bitcoins than one has, it means that transactions can be accidentally nullified.