In recent days, the crypto digital asset market, which has been in the haze for a long time, has ushered in a sunny day that has not been seen for a long time. According to the data of OKCoin Bank, since July 17, Bitcoin has risen for six consecutive times, and on July 21, it reached a peak of 19800 yuan.

In an effective market, most of the valuable information has been reflected in the K-line trend. As far as Bitcoin or the whole crypto digital asset market is concerned, the risk of Bitcoin bifurcation is an important trigger for the previous sharp decline. The recent recovery is also largely due to the recognition of BIP91 scheme by mainstream miners. In the short term, the alarm of Bitcoin bifurcation has been lifted.

However, the alarm has not been completely lifted. Within three months of the successful activation of BIP91, there will also be a hard fork in the expansion of the 2M block. At that time, the real test will come.

Test what? To test the tenacity of the Bitcoin blockchain, if we split up because of several conflicts of interest, Bitcoin will no longer be the popular Bitcoin, and its value base will inevitably be seriously damaged, which is the result that we do not want to see.

Therefore, the test of Bitcoin is just beginning.

Where does the risk of blockchain branching come from?

For most investors, blockchain branching is still a strange word. As the name implies, the so-called bifurcation means that the original blockchain is split into two or more blockchains. Since blockchains are public ledgers for recording bitcoin transactions, since there are multiple blockchains, which means there are multiple bitcoin ledgers of different versions, it is naturally considered that there are multiple bitcoins.

Just like Ethereum, the event of The Dao caused a hard bifurcation, which resulted in two blockchains, namely ETH and ETC.

How do blockchain forks come about?

Let's start with the consensus mechanism of the blockchain. As we all know, the blockchain is jointly maintained by point-to-point decentralized nodes. There is no the final say authority here. The orderly operation of the blockchain depends on everyone's consensus, that is, there is a set of recognized standards for key issues such as which transactions are acceptable and which nodes have accounting rights. This set of standards is deployed in the underlying blockchain protocol for automatic execution.

The problem is that when the nodes in the blockchain run different versions of the underlying protocol, there may be inconsistencies in the consensus mechanism, that is, some nodes agree to access the blockchain and some nodes refuse to acknowledge that some blocks are considered to be in compliance with the rules. At this time, without updating the underlying protocol to keep consistent, the blockchain will naturally split into two or more.

Someone has to ask why the node runs different versions of the underlying protocol? Wouldn't it be better if everyone updated in time? It seems to be a simple problem to update software in time, but it is not.

One is that blockchain is a decentralized network operation mode, with nodes scattered around the world. The time zones are different, and some are continuously online and some are often offline. It is impossible to achieve all updates of nodes at the same time. Therefore, the upgrading of the underlying protocol of the blockchain almost inevitably leads to the blockchain bifurcation; Second, based on various factors, some nodes are against upgrading, which is the fundamental reason for the long-term bifurcation of the blockchain.

Why do some nodes object? It is not difficult to understand. In the commercial society, it is impossible for everyone to agree with a certain point of view or approve of an upgrade. Sometimes, if there is a serious conflict of interest, it is normal to split into two or more factions. Unfortunately, there are serious conflicts in the community whether the underlying Bitcoin protocol is upgraded or not.

Conflicts of interest and temporary compromises

The author mentioned in previous articles that the current underlying protocols of Bitcoin blockchain have some limitations, which have seriously restricted the development and prosperity of Bitcoin. First, the block size is limited. The current Bitcoin block size is 1M, which can only handle 7 transactions per second, seriously lagging behind the development needs; Second, the scalability of Bitcoin blockchain is poor, making it difficult to deploy more complex innovative applications.

As far as this conflict is concerned, the focus is on block expansion. The expansion of the block has become a consensus, but there are different opinions on how to expand it.

The ideal plan of the miners

As far as the miners are concerned, they hope to directly release the restrictions on the block, and have successively put forward different expansion plans such as 8M, 4M and 2M.

The Bitcoin Core team objected. Whether upgrading to 2M or 8M, with the popularity of Bitcoin transactions, it will not be enough one day, which means that capacity needs to be expanded. The larger the block, the higher the requirements for computing power, which means that fewer and fewer nodes have the ability to run the whole node blockchain, which will easily lead to the centralization and monopoly of computing power, that is, the blockchain can only be maintained by several large mining pools.

Ideal solution for the Core team

As far as the core team is concerned, it is hoped to deploy SegWit (Segregated Witness), that is, through the separation of transaction information and verification information, when part of the data is removed, it will make room for more transactions. In this way, the transaction throughput of the whole Bitcoin network will also be improved, which will achieve the effect of block expansion in disguise. After the deployment of isolation witness, lightning network can also be introduced subsequently to move small transactions away from the blockchain, which only undertakes the final clearing function, greatly reducing the load of the blockchain.

The miners objected. Isolation witness or lightning network will fundamentally damage the interests of miners. Miners have two motivations for mining: one is the bitcoin issuance income brought by the block bookkeeping right, and the other is the bookkeeping transaction fee income. If the transaction is taken away from the blockchain, it means that there is no need to pay fees to the miners, which is obviously unacceptable.

The problem is that without the support of the miners, the upgrading of the underlying Bitcoin protocol will become an empty talk.

Conflict and compromise

As the two sides failed to reach an agreement, the bitcoin expansion and upgrade was delayed from 2015 to 2017. The Core team took the lead and planned to vigorously implement the BIP148 scheme to achieve the purpose of deploying isolation witness. Its activation date is in the early morning of August 1, 2017. At that time, if the nodes represented by the miners fail to follow up the upgrade of BIP148, the Bitcoin network will be split, including upgraded BIP148 nodes and non upgraded nodes. The Bitcoin blockchain will also be divided into two parts.

In a sense, patience has been polished. Since we can't reach an agreement, we should split up.

In view of the bifurcation risk of BIP148 scheme, since July 10, the transaction price of Bitcoin began to plunge. In just seven trading days, the closing price of Bitcoin fell from 17762 yuan to 13500 yuan. The whole crypto digital asset market is full of sorrow, and there are many cuts in the waist and chest.

As a result, a compromise BIP91 scheme appeared and was supported by the miners. The BIP91 scheme aims to lock the isolation witness before August 1 and is compatible with BIP148 protocol. It means that as long as BIP91 is successfully activated before August 1, both the nodes running the BIP91 protocol (supporting the proposal of the miners) and the nodes running the BIP148 protocol (supporting the proposal of the Core team) will be compatible with each other and will not bring about the bifurcation of the blockchain.

Thanks to the support of the miners, the BIP91 scheme was successfully activated on July 21, which means that the BIP148 scheme to be activated on August 1 has become harmless and the blockchain bifurcation alarm has been removed. Stimulated by this news, Bitcoin rose rapidly.

In the next three months, there is still a war

But the problem is not over. BIP91 is supported by miners because it is a bundled scheme of "isolation witness+2M block expansion". First, the isolation witness is deployed, and then the 2M block expansion agreement is automatically upgraded within three months, taking into account the interests of miners and the needs of the Core team to deploy isolation witness.

The problem is that the BIP91 scheme locks the isolation witness in advance. It only needs to reach the threshold of 80% computing power, and does not require the support of the Core team. This means that the activation of BIP91 has not fundamentally resolved the dispute between the two sides - block expansion, but only delayed the time.

The BIP91 deployment isolation witness is no problem, but the Core team may not agree to the 2M block expansion within three months. Therefore, the Bitcoin blockchain will still face the risk of bifurcation in the next three months.

The value of Bitcoin comes from the stable ecosystem and the investor confidence it inspires. If the interests of several parties can easily cause bifurcation, the investor's confidence in Bitcoin will be affected. If confidence is fundamentally shaken, how can there be a good future?

Therefore, the war is not over, and the test of Bitcoin has just begun.