On Tue, May 12, 2015 at 7:48 PM, Adam Back wrote: > I think its fair to say no one knows how to make a consensus that > works in a decentralised fashion that doesnt weaken the bitcoin > security model without proof-of-work for now. > Yes. > I am presuming Gavin is just saying in the context of not pre-judging > the future that maybe in the far future another innovation might be > found (or alternatively maybe its not mathematically possible). > Yes... or an alternative might be found that weakens the Bitcoin security model by a small enough amount that it either doesn't matter or the weakening is vastly overwhelmed by some other benefit. I'm influenced by the way the Internet works; packets addressed to 74.125.226.67 reliably get to Google through a very decentralized system that I'll freely admit I don't understand. Yes, a determined attacker can re-route packets, but layers of security on top means re-routing packets isn't enough to pull off profitable attacks. I think Bitcoin's proof-of-work might evolve in a similar way. Yes, you might be able to 51% attack the POW, but layers of security on top of POW will mean that won't be enough to pull off profitable attacks. -- -- Gavin Andresen