Author: Peter Todd 2013-11-04 16:07:16
Published on: 2013-11-04T16:07:16+00:00
The email conversation is about the concept of selfish mining in Bitcoin. Ittay asks Peter how he can guarantee that the majority mines on the non-selfish block. In response, Peter explains that as long as miners switch to the block with the most hashing power, this forms a feedback effect that quickly brings everyone to consensus. If all miners quickly come to consensus and are all mining on the same block, there's nothing the attacker can exploit. Peter uses an example of an attacker named Alice who is 100 blocks ahead of the main network with just under 50% of the hashing power. When the main network finds a block n+1, Alice can either publish her own n+1 block or do nothing. If she does nothing, the main network will find block n+2 faster than she finds n+101, so eventually she loses. In Alice's attack, she publishes to a subset of nodes strategically, splitting the hashing power between nodes working to extend her n+1, and the other n+1 found. However, with near-target headers, very quickly all hashing power will come to consensus and all work to extend the same block, either theirs or Alice's. Thus, eventually Alice will lose. There is still a slight advantage for Alice in that it takes some time for the whole network to come to consensus, but this is a much slimmer margin, maybe a few percentage points, so at best Alice might need, say, 45% of the total hashing power.
Updated on: 2023-06-07T19:07:09.170601+00:00