Author: Jorge Timón 2016-02-05 10:20:28
Published on: 2016-02-05T10:20:28+00:00
This context is a discussion on proposed changes to the semantics of the sign bit of the "version" field in Bitcoin block headers as a mechanism to indicate a hardfork is deployed. The proposal suggests using a flag block which would serve as the "point of no return," and could be determined by block height or the first block with GetMedianTimePast() greater than a threshold. The exact mechanism is out of the scope of this proposal, but the threshold is consensus critical, must be publicly verifiable with only blockchain data, and SPV-friendly. The proposal is compatible with BIP9, which could be employed to measure miner support towards a hardfork proposal and determine the height or time threshold of the flag block. However, there is disagreement over whether BIP9 should be used for hardforks or if miners should have any voice in the decision. Furthermore, controversial hardforks could create two chains that survive for unbounded amounts of time. While the proposal recommends using median-time-past and height for hardforks, an emergency hardfork may need to avoid them for simplicity, and it's suggested that they don't need to be mandated as such in this proposal.
Updated on: 2023-06-11T03:35:21.118077+00:00