Talk about the soft fork upgrade specification BIP8-soft fork method in the post-miner era

We have mentioned the soft fork upgrade specification BIP9 before. BIP9 can be said to be a well-designed soft fork upgrade solution that can upgrade multiple forks at the same time and the process is also scientific and reasonable.

BIP9

Let’s briefly review the main features of BIP9:

1. A high voting threshold of 95%. The block vote must reach a support rate of more than 95% to enter the lock-up period and then trigger activation.

2. A voting time window is set with a start and end time. Soft forks that are not activated within the window period can only be terminated or reset to initiate a new round of voting.

3. The block time uses the median block time of the 11 adjacent blocks.

As of now (February 2019), BIP9 has been used twice:

1. CSV (BIP68, BIP112, and BIP113)

2. SegWit (BIP141, BIP143, and BIP147)

Everything went well in the CSV soft fork, but the SegWit soft fork was delayed for more than half a year in the voting phase, and the block voting could not reach the 95% activation threshold, which led to the emergence of BIP148 (UASF, user-activated soft fork) and BIP91. The time period set by SegWit in BIP9 is: November 15, 2016 to November 15, 2017.

Here we briefly talk about BIP148 and BIP91. Only by understanding this process can we understand why BIP8 exists (these things actually happened a long time ago, in mid-2017, almost two years ago). It is worth mentioning that the code of BIP148 and BIP91 has never entered the code base of the Bitcoin Core version.

BIP148

BIP148, more commonly known as UASF, aims to force the activation of SegWit: if the block time is between August 1, 2017 and November 15, 2017, and SegWit has not yet been activated or has not entered the lock-up period, the block that does not support SegWit voting will be directly rejected. BIP148 is declared and implemented by users updating the code themselves, downloading the Bitcoin Core code and then patching it.

UASF is a very radical upgrade method, which directly ignores the vote of miners' computing power. Regardless of whether the computing power votes for SegWit, these UASF full nodes will directly discard non-SegWit blocks. This was a bolt from the blue for miners and computing power at a time when miners and computing power were still highly recognized: it was directly ignored!

Of course, many exchanges have rehearsed this event: assuming that a fork will occur, they have listed futures for the two currencies after the fork and left the price to the market to judge.

BIP91

BIP91, which also aims to activate SegWit, does so indirectly by lowering the SegWit activation threshold to 80%. It is deployed in a similar way to BIP9:

1. The activation period is from June 1, 2017 to November 15, 2017.

2. The block time window is very short, no longer 2016 blocks as in BIP9, but 336 blocks, about 2.33 days.

3. The activation threshold is 80%, no longer 95% of BIP9.

BIP148 (UASF) directly bypasses miners and is activated directly by full nodes, while BIP91 still gives the choice to miners: activation through block voting. In the end, under the strong community pressure led by UASF, BIP91 quickly passed the 80% block voting threshold and entered the lock and activation. Once BIP91 is activated, it means that subsequent blocks must vote to support SegWit, which indirectly facilitates SegWit to pass the 95% block voting threshold and lock and activate.

The above is the historical process of how UASF&BIP91 indirectly promoted the activation of SegWit after SegWit activation was blocked for more than half a year.

BIP8

BIP8 is an improvement on BIP9:

1. A more precise block height window is used instead of the block time window, eliminating the instability of block time.

2. The statistical period is still 2016 blocks, consistent with BIP9.

3. There is almost no failure state, unless the height set at the beginning of coding is already a past height.

4. Set the activation starting block height. Once the current height is greater than the starting block height, the calculation of whether to activate will begin. The starting block height must exceed the current height by 4320 blocks, which is about 30 days.

5. Set a cut-off block height. Regardless of whether the vote is passed or not, forced activation will be performed when the cut-off block height is reached. The cut-off height is usually 52416 blocks after the starting height, about one year.

6. Before reaching the cut-off block height, if the vote exceeds the threshold, which is consistent with BIP9 at 95%, the lock-up period will be entered in advance and activated accordingly.

BIP8 States

In summary, if a soft fork follows the BIP8 activation mechanism, once deployed, miners can vote to activate it in advance, or it can be automatically activated when the cutoff height is reached one year later.

The main significance of BIP8

1. The veto power of miners has been cancelled: either vote to activate in advance, or do not vote and wait for the deadline to be reached for automatic activation.

• Vote turns into Signal.

• The size of computing power is the result of price. Strictly speaking, the daily output of legal currency on the chain determines the scale of computing power.

• Prices are determined by market supply and demand, and are reflected in consensus-driven prices.

2. The community’s decision-making mechanism has undergone a fundamental change: voting in a small circle has become universal suffrage to a certain extent.

• Whether it is computing power voting or coin holding voting, due to the existence of an intermediate proxy layer (such as mining pools, exchanges, wallets, etc.), it is inevitable that it will eventually become a small circle voting to a certain extent.

• One full node is one vote, and all nodes constitute the broadest consensus.

• Full nodes restrict computing power on one hand, and code on the other. Neither mining tyrants nor code tyrants can constrain the behavior of full nodes.

postscript

Since the time of Satoshi Nakamoto's white paper, most people have firmly believed in the democratic concept of "One CPU One Vote". After the activation of SegWit in 2017, which also resulted in the hard fork of Bitcoin Cash (BCH), it has finally been completely transformed. Everyone has discovered that only full nodes are the ultimate fortress and weapon, and running full nodes is a right that no one can deprive of given by the equal and free Internet.

refer to

BIPs https://github.com/bitcoin/bips/blob/master/bip-0009.mediawiki https://github.com/bitcoin/bips/blob/master/bip-0008.mediawiki https://github.com/bitcoin/bips/blob/master/bip-0148.mediawiki https://github.com/bitcoin/bips/blob/master/bip-0091.mediawiki

Source: Bitcoin Lab (https://panzhibiao.com/2019/02/11/bip8/)