Quote from: roalwe on April 28, 2013, 04:18:08 PM

Personally, I am not convinced it is needed.

There was so far... about 2 "emergencies" with the blockchain (that "generate a lot of bitcoins" bug, and the doublespend in the recent fork) none of which were exploited by a real malicious party.

As far as I can tell, many major banks have a less stelar record.

It doesn't seem to me that bitcoin's "the hashiest chain wins" approach is "broken", so maybe we should refrain from "fixing" it.

My issue was always that I didn't like the idea of a hidden chain attack. If someone has a bunch of hashing power (very unlikely) and generates a chain offline, then publishes it, overturning a huge number of blocks, we pretty much just have to sit and watch. Of course, we can then intervene after the fact to put it back.

But it seems like a better way would be to devise a scheme where the attacker would be unable to keep their longer chain secret. That is why I like the exponential difficulty method. Under ordinary circumstances, and even honest chain forks, the network would operate as usual. But a high powered attacker is fighting against the clock, and people can look at the number of blocks protecting their transaction, calculate the exponential, and evaluate the risk with something more closely approaching certainty.

The cost is, however, that the notion of correctness gets a little fuzzy. I still think that it is better to protect the network as a whole, in exchange for individual nodes needing manual intervention during some attacks. Gmaxwell gives the opposing view, which is widely shared. It is a really critical part of bitcoin, and won't be tweaked lightly, if ever.