No. of Recommendations: 3
amj101 was talking about a 51% attack, as opposed to a fork. A 51% attack means new blocks with new rules are added to the old chain.
I've never truly understood how it works. Does it require 51% of mining capacity or does it require 51% of bitcoin owned to vote on such changes?
And if the former (51% of mining capacity), how is that determined since mining capacity changes constantly.
I also wonder what might happen when quantum computing becomes real and practical. Since, in theory at least, quantum computing can make short work of decrypting well-encrypted stuff, perhaps it could also make short work of mining (calculating hashes). And if it can, maybe the first big quantum computing setup could control 51% of mining capacity shortly after it gets turned on.
