Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread rob . golding
> The Problem: > Say Alice built a block, A1, from previous block 0. She doesn't let > other miners know about it. She then works on A2 with previous block > A1. Bob on the other hand is still working on B1 with previous block > 0. Bob now finds a block and he broadcasts it. The assumption here is

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Quinn Harris
On 11/05/2013 08:03 PM, Drak wrote: On 5 November 2013 22:07, Quinn Harris > wrote: I don't think choosing the block with the lowest hash is the best option. The good and bad miners have an equal probability of finding a lower hash. But after Alice

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Gavin Andresen
> What do you think? > I would like to be convinced that there is, actually, a real-world problem before thinking about potential solutions. I'd like to see more analysis of the proposed selfish-mining algorithm at a particular share-of-network and gamma=0 (assume second-broadcast blocks always l

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Drak
On 5 November 2013 23:06, Gregory Maxwell wrote: > On Tue, Nov 5, 2013 at 2:15 PM, Drak wrote: > > If I understand the issue properly, this seems like a pretty elegant > > solution: if two blocks are broadcast within a certain period of > eachother, > > chose the lower target. That's a provable

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Gregory Maxwell
On Tue, Nov 5, 2013 at 2:15 PM, Drak wrote: > If I understand the issue properly, this seems like a pretty elegant > solution: if two blocks are broadcast within a certain period of eachother, > chose the lower target. That's a provable fair way of randomly choosing the > winning block and would s

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Drak
On 5 November 2013 22:07, Quinn Harris wrote: > I don't think choosing the block with the lowest hash is the best > option. The good and bad miners have an equal probability of finding a > lower hash. But after Alice finds a block she can easily determine the > probability that someone else wil

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Drak
On 5 November 2013 20:51, wrote: > Possible Solution: > If N amount of blocks built of the same previous block are received within > a time frame of T mine on the block with the lowest hash. > > Logic: > In order for Alice to pull of this attack she not only has to propagate > her blocks first sh

Re: [Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread Quinn Harris
I don't think choosing the block with the lowest hash is the best option. The good and bad miners have an equal probability of finding a lower hash. But after Alice finds a block she can easily determine the probability that someone else will find a lower hash value that meets the difficulty

[Bitcoin-development] Possible Solution To SM Attack

2013-11-05 Thread colj
Preliminary: Alice has the ability to hear of a block before all other miners do. The Problem: Say Alice built a block, A1, from previous block 0. She doesn't let other miners know about it. She then works on A2 with previous block A1. Bob on the other hand is still working on B1 with previous b