Proposal: Demonstration of Phase in Full Network Upgrade Activated by Miners

Summary:

The Demonstration of Phase in Full Network Upgrade Activated by Miners proposed by LIN Zheming is a collaborative product of the Chinese bitcoin community. The proposal aims to protect mining nodes and non-mining nodes during protocol upgrading while avoiding monetary losses from chain splitting. It will incorporate any upgrade that affects non-mining nodes, and miners signal their support with versionbits. After the activation condition is met, majority miners will set a new block versionbits after the first grace period (a difficulty change of 2016 blocks). Transactions from nodes not upgrading will not be relayed nor included in blocks with new versionbits. This method protects the asset security of wallet nodes and provides additional incentives for them to upgrade their protocol.Protocol upgrading will phase in over three stages with an optional fourth stage to integrate codes of protocol upgrade. Mining nodes signal using BIP9, and the next level will activate after 55% (1109) of 2016 blocks have the signal. After a first grace period of 2016 blocks and total signalling blocks passed 2218 of 4032 blocks, miners broadcasting blocks with new versionbits in block headers will orphan blocks with old versionbits. At this stage, all nodes can send transactions with new versionbits, and transactions with old versionbits will be compatible. After 4032 continuous blocks with new versionbits, mining nodes will start to refuse transactions with old versionbits. Only transactions with new versionbits can be relayed and included in blocks. The codes dealing with protocol upgrade can be integrated in the third stage.The benefits of this method are that it requires only a majority of miners to signal their support for activation, reducing the possibility of delaying network upgrades by controlling a small amount of computing power. Wallet node transactions are not affected during the two grace periods, giving them enough time to upgrade their software. Version information is contained in block headers and does not affect SPV mining processes.However, this method could cause problems with systems like lightning network that rely on reliable confirmations of transactions as part of their security models. The activation of network upgrades only requires a majority miner signal with 55% miners being in the longest chain after 340 blocks, with 99.9% certainty. This will reduce the possibility of delaying network upgrades by controlling a small number of hashing power. After 51% signalling, all miners are expected to upgrade within the first grace period. During the first two grace periods, non-mining nodes are not affected and have enough time to upgrade their software. Versionbits included in block header do not influence SPY mining. However, after two grace periods, all nodes must be upgraded; otherwise, they cannot send transactions or get any confirmations. Compared with forming new consensus among nodes, this situation is no worse than before. The ledger in non-mining wallet nodes is honored and reserved. Users of off-chain wallet services can decide whether or not to follow the service providers after getting public notification from them. Protocol upgrades in the future can be bonded with the upgrades of nodes, and the upgrades can activate through miners vote independently. This gives nodes enough time to be upgraded to support new protocols. Even if miner activation fails, the situation will not worsen, and the status quo will remain.There are risks involved with the fluctuation of hashing power affecting the result of the longest chain. Miners could also falsely signal to avoid being orphaned, and non-mining wallet nodes may not distinguish the false signal from the true signal. Non-mining wallet nodes could also false signal without supporting the new protocol, but genuine nodes should follow the proven result provided by miners' votes. Additionally, miners and non-mining nodes could conspire to fork using old protocol consensus. The implementation of these upgrades is yet to be determined.

Updated on: 2023-06-12T02:35:05.976350+00:00