Published on: 2017-02-06T18:06:22+00:00
Bitcoin developers have proposed a series of consensus changes to the Bitcoin network, which are outlined in the bitcoin-dev mailing list. These changes include modifications to the pre-hardfork policy, sighash limitations, transaction weight definitions, and block weight growth over time.One proposal is to introduce a new extended and flexible header in the witness field of the coinbase transaction. This extended header allows miners to include any information they want, which bitcoin users can ignore. It also makes the network merge-mining friendly. Additionally, there is space for miners to include non-consensus enforced bitcoin-related data that is useful for fee estimation.Other proposed changes involve the coinbase transaction format and the witness merkle root. The sign bit in BIP9 would be ignored, and a full hardfork with more drastic changes would be implemented to address issues with SHA256 shortcut like ASICBoost and block withholding attacks.To activate the hard fork, at least 51% of miners are needed to build the new block format. The hard fork time is determined by a consensus of the community to prevent splitting. A special BIP9 softfork has been defined to relax the size limit of Header 2 and Header 3, allowing expansion without a hardfork. However, these changes would require firmware upgrades for all existing miners and light wallet upgrades, which are not expected to happen until at least two years after the initial activation of the hardfork.An experimental implementation of these proposals can be found on GitHub, but it is still untested and not independently reviewed. Therefore, it should not be used in production, although it may work fine on testnet.Furthermore, a new transaction weight formula encourages responsible use of UTXO, while the block size will grow linearly until a certain limit. There is also Sighash O(n^2) protection for legacy (non-segwit) outputs.Some aspects of the proposals are still under development, such as automated testing, post-hardfork support for old light wallets, and wallet support for anti-tx-replay. Additionally, there is no new p2p message to transmit the secondary header, and there is currently no full mining or mempool support.In summary, Bitcoin developers have proposed a hardfork to increase the block weight limit and make changes to the transaction and coinbase formats. These proposals aim to improve the efficiency and functionality of the Bitcoin network, but they are still in the development stage and should not be used in production at this time.
Updated on: 2023-08-01T19:32:18.790817+00:00