Author: Mike Brooks 2020-09-25 17:35:36
Published on: 2020-09-25T17:35:36+00:00
In a bitcoin-dev mailing list, Mike responded to Jeremy's concern about the implementation of fitness tests in Bitcoin. Mike clarified that fitness tests have a 100% chance of accepting a new block and only a 50% or less chance for replacing an already mined block. This feature keeps incentives moving forward and makes it more expensive to replace hard work rather than contributing to new work, which is useful for stability. Mike also explained that the "first seen" feature has some undesirable attributes, including the possibility of a miner ignoring a solution block and still having an unpenalized opportunity to replace it. This is possible with the first scene and an eclipse of the network to dictate which solution will be seen first by affected nodes. The fitness test introduces a neat boundary, whereby it is always cheaper to make a new block than replace the existing block, making it difficult for a malicious miner to exceed the work needed to generate a new block.Jeremy was skeptical of the properties of this change and preferred the first-seen policy level decision because it has the nice property that once a block is received, there is a substantially reduced incentive to try to orphan it because the rest of the network is going to work on building on that block. With fitness, there is a 50% chance of a mined block being accepted, so floating point would have the effect of destabilizing consensus convergence at the tip. However, Jeremy acknowledged that using a fitness rule like this could be useful if both blocks are seen within a very small window, decreasing partition risk if it's likely the orphan was mined within close range of the other.
Updated on: 2023-06-14T15:31:43.075140+00:00