Bitcoin Unlimited Foundation came to China to give technical presentations to miners and Bitcoin enthusiasts

Chapter 0 Introduction

The BU Foundation came to China last week to give technical reports to miners and Bitcoin enthusiasts, and gave two special reports on Bitcoin Unlimited in Beijing and Shenzhen respectively.

I attended the Shenzhen conference and assisted the organizers with some translation work. Now I will write a review of the conference.

Chapter 1 Background

The Bitcoin Unlimited Foundation is a non-profit organization registered in the United States. Its mission is to promote the development of Bitcoin. Currently, its main focus is on the expansion of the Bitcoin protocol. Therefore, its main external image is a Bitcoin development group called the Bitcoin Unlimited Development Group.

Five members came to China this time, including BU Foundation Chairman Andrew Clifford, Strategist Jerry Chan, Chief Developer Andrew Stone, Developer Andrea Suisani, and Developer Peter Tschipper. It was a strong lineup.

The main purpose of the BU Foundation's visit to China this time is to introduce the latest technical features that Bitcoin Unlimited brings to the Bitcoin network, and to introduce the BU Foundation to Chinese Bitcoin enthusiasts.

The special report held in Shenzhen was hosted by bitbank and Bitcoin.com.

Okay, let’s get straight to the point and see what exciting content this meeting has.

Chapter 2 : Andrea Suisani introduces Bitcoin network performance improvement techniques

The first report was by developer Su Sanni, who introduced the latest technical features that Bitcoin Unlimited has made for the Bitcoin network, including thin blocks ( Xthin ), extreme verification blocks ( XVal ), and accelerated block forwarding ( Xpedited ).

Bitcoin is a P2P network. One of the main tasks of this network is to transmit blocks between nodes. Especially for mining nodes, the speed of block propagation and the time of block verification are very important. Because this involves whether the blocks mined by miners will be isolated, the efficiency of Bitcoin block propagation has been very low for many years. In particular, due to the existence of the national firewall, the efficiency of block propagation for Chinese miners is even worse than that of foreign miners.

Susanni vividly explained that Bitcoin transactions and blocks are the propagation process in the P2P network. A block basically contains most of the transactions of the entire network for about 10 minutes, and these transactions have actually been received by a node before the block reaches it. This is equivalent to repeatedly broadcasting and receiving the same data. Thin blocks are a technology that reconstructs blocks through transaction data in the node memory pool instead of asking nodes to repeatedly receive the entire block. Thin blocks only need to accept block header data containing proof of work.

By using thin block technology, the data transmission efficiency of the Bitcoin P2P network has been greatly improved, which is equivalent to accelerating the network by 5.6 times, reducing the amount of data that needs to be transmitted by 24, and optimizing the routing of blocks through the national firewall, making the speed at which Chinese miners' blocks pass through the firewall 9.7 times faster.

The extreme verification block and block acceleration forwarding, together with the thin block technology, have greatly optimized the network data transmission performance of the Bitcoin network. Su Sanni said very happily that these technologies can allow the current Bitcoin network infrastructure to handle 20M blocks without any hardware upgrades. It can increase the transaction processing speed of the Bitcoin network from the current 3 transactions/second to 60 transactions/second. And it will not affect decentralization at all. There will be no bottlenecks in network bandwidth, CPU clock and hard disk capacity.

Su Sanni finally focused on explaining the Bitcoin Unlimited development team’s code quality inspection process for software development, emphasizing how the high reliability of their software development is guaranteed.

Chapter 3 Jerry Chan introduces Bitcoin Unlimited’s Emergent Consensus technology

The current Bitcoin network mainly runs the Bitcoin Core client. Under the current network rules, if we ask miners to generate blocks larger than 1M, it will be considered illegal. The 1M block obviously limits the scalability of Bitcoin. Jerry Lee introduced how Bitcoin Unlimited allows the Bitcoin network to flexibly set the block size by asking miners to follow four simple rules without causing any consensus breakdown.

Jerry vividly introduced the concept of "emergent consensus" from the phenomenon of how wild geese maintain a highly orderly flying formation.

The four rules defined by the Bitcoin Unlimited client are:

1. Always track the tip of the largest proof-of-work chain

2. The maximum block size (MG) that can be generated when mining

3. Using the EB parameter to mark delayed acceptance of larger block sizes

4. Use AD parameter to mark the block depth to delay acceptance of larger blocks

In his PPT, Jerry presented a network model that uses these four rules to achieve elastic block size. He introduced in great detail: the various sizes of blocks that miners may mine, how the acceptable block size of the entire network becomes larger, under what circumstances larger blocks will be isolated, etc.

The Bitcoin network needs this emergent consensus, which is a great solution to the block capacity problem. After the meeting, Liu, co-founder of Bikan, asked Jerry whether this technology would bring complexity to the network, especially compared with Segregated Witness, which one is more complex? Jerry replied that in terms of code complexity, emergent consensus is very efficient and concise, while Segregated Witness is the opposite. In terms of the complexity of network rules, emergent consensus does not bring a more complex dual-block structure to the data structure of the block, while Segregated Witness is essentially a dual-block structure that extends the block, so Segregated Witness is more complex, not only more complex at the code level, but also Segregated Witness has significantly modified the storage rules and propagation rules of the block.

Chapter 4 Andrew Clifford introduces the organizational structure of the BU Foundation

The last speech was given by Andrew, Chairman of the BU Foundation, who introduced the BU Foundation’s charter, organizational structure, members, principles, personnel appointment and dismissal mechanism, and the process of applying to join the foundation.

The BU Foundation is a non-profit organization officially registered in the United States. The foundation has a "constitution", namely the Bitcoin Unlimited federal charter, personnel appointments and dismissals are based on the charter, the foundation also has a legal financial charter, and a way to raise funds.

Of course, the most important thing is how the foundation maintains the Bitcoin network, especially to ensure the software improvement and upgrade of Bitcoin Unlimited. Andrew introduced the development route proposal of BU.

Bitcoin Unlimited has now prepared for the expansion of Bitcoin blocks. In terms of technical features, it has prepared the emergent consensus to achieve elastic block size limits, while solving the Sigops attack, and preparing thin blocks, accelerated forwarding, extreme verification, and parallel block verification to improve network performance. These technologies have been deployed on the Bitcoin network, but the emergent consensus still needs to wait for enough miners to support it to initiate a hard fork in the entire network to activate it.

If the Bitcoin network successfully implements a hard fork upgrade, BU's next development plan is to fix transaction scalability, and will choose between elastic transactions and the hard fork version of isolated witness. This will greatly facilitate the deployment of lightning networks and side chains, and also provide more extensive convenience for reprogramming and development on Bitcoin.

In order to achieve large-scale expansion of the Bitcoin network, BU developers are now preparing UTXO integration ( UTXO commitments ), SPV node support technology ( SPV supporting nodes ), fraud proofs ( fraud proofs ) and block sharding ( block sharding ), which will realize the recovery of hard disk space and simplified payment confirmation in Sections 7 and 8 of the Satoshi Nakamoto white paper. After these technologies are completed, Bitcoin light nodes will be more secure and make the Bitcoin network infinitely scalable. The Bitcoin network nodes can be expanded to hundreds of millions.

The final grand goal in the roadmap is to use child chains to achieve Bitcoin's zero-confirmation payment security and block propagation. This technology will reduce Bitcoin's payment confirmation time to seconds, and child chain technology will also make the Bitcoin network more efficient. It will truly expand the Bitcoin network to the Internet level and prepare for 50 million on-chain transactions per day.

Chapter 5: Passionate Bitcoin Jesus

The leader of the conference, Bitcoin Jesus (Roger Ver), also gave a passionate speech at the conference. Roger analyzed the current status of the target Bitcoin economic ecosystem, especially the current status of Bitcoin consensus discussions.

Roger hopes that everyone will not succumb to the core's censorship of speech, and express their views and opinions openly, freely and democratically.

There is no "official" version of Bitcoin, and more Bitcoin protocol client implementations like Bitcoin Unlimited should be encouraged. This allows for diversity in innovation, which is much needed in our young but growing industry.

There is no need for leaders in the Bitcoin world, and no individual has the right to issue orders above the entire community.

Finally, with the consent of the BU Foundation, I uploaded all the PPTs of this technical report to Baidu Cloud Disk. You can download the Chinese and English versions. Download link:

Link: https://pan.baidu.com/s/1gfsQJIj Password: 45bb

Chapter 6 Conclusion

The current era of Bitcoin is a powerful United States and a rising China. Chinese and Americans are the main practitioners of Bitcoin, especially in the fields of protocol development and mining. The two fields should have more in-depth exchanges and cooperation. The Bitcoin community has fully demonstrated how difficult it is for practitioners in China and the United States to communicate in the dispute over capacity expansion that has lasted for more than three years. Both sides need to overcome cultural differences and language differences, especially in terms of interests, and both sides need to find a win-win path.

I hope that Bitcoin Unlimited Foundation can do more positive work for the development of Bitcoin. Thank you BU Foundation for popularizing technology to us Bitcoin enthusiasts.