Free and Easy Weekly Review 丨 Can't Blockchain Privacy Protection and Regulation Have Both? Actually!

Introduction: As more and more countries upgrade blockchain technology to national strategic status, the participants and strength of relevant research will also be significantly enhanced. This week's report will cover the latest academic papers, hard-core technical articles on blockchain related disciplines, and the technological progress of major blockchain projects, providing a reference for blockchain developers, entrepreneurs and investors to grasp the development trends and opportunities of blockchain. .


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The following is a selection review of last week's content, enjoy ~

I. Selected Academic Papers of the Week

1.1 WaterCarver: A blockchain privacy protection system based on an account model

A blockchain system based on the Account model (such as Ethereum) is widely used for its ease of use and native support for smart contracts. However, many users are not willing to leave a permanent public on the chain. Records, therefore, users' privacy issues have become a major bottleneck for further adoption of the blockchain.

Generally speaking, user privacy includes transaction confidentiality and anonymity. Although the confidentiality of transactions can be easily protected using confidential transaction (CT) technology, in blockchain systems based on account models, anonymity faces A big challenge, because every transaction in the system inevitably updates the account balance of the sender and receiver of the transaction.

Therefore, the privacy scheme of the account model is also one of the hot research directions in the current blockchain industry. For example, Zether is a solution to solve the privacy problem of Ethereum . It can not only decentralize account-based transactions. Providing confidentiality and anonymity, this solution can be deployed via Ethereum's smart contracts, which makes it easy to implement, but it has the disadvantage of making transactions relatively expensive.

Researchers from Shenzhen Wangxin Technology and Clemson University Department of Electrical and Computer Engineering (Jiajun Xin et al.) Also recently proposed a privacy protection protocol based on an account model and called it WaterCarver (named from Idiom "Chou Zhou Qiu Jian".

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This scheme utilizes the latest verifiable shuffle scheme to construct confidential transactions. In addition, the paper also mentions two supervisory subsystems, (A) Bulletproof supervisory subsystem, and (2) Verifiable Shuffle. Regulatory subsystem.

In these two subsystems, in addition to the two roles of prover and verifier, there is a special role of regulator, which leaves room for forward security supervision. .

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The experimental results show that the TPS of this system is considerable, and to improve it, there are several options to choose from: (1) use MPC batch processing Bulletproof, (2) use multi-exponentiation technology to further optimize NIZK , (3) use aggregate signature technology to achieve faster signature verification, (4) some common optimization methods, such as using the GPU to calculate faster elliptic curves, or simply use stronger hardware to improve.

Comment: The WaterCarver scheme considers privacy protection and supervision at the same time. Such a scheme is obviously very suitable for domestic blockchain enterprises. This research is undoubtedly of reference value .

1.2 SoK: Overview of Blockchain Sharding Schemes

In addition to privacy protection issues, "blockchains" also generally face scalability issues. To solve this problem, people have proposed many methods, such as off-chain capacity expansion and directed acyclic graphs. (DAG) solutions, however, they also have inherent disadvantages, such as forming parasitic chains.

In addition, performance (such as throughput and latency) is also very important for blockchain systems, and sharding is a currently very promising alternative that can overcome the scalability in the blockchain Problems and performance issues. Up to now, researchers have proposed many sharding protocols. However, we lack relevant review literature. Researchers from the University of Connecticut and Emerson have systematically and comprehensively implemented blockchain sharding technology. Looking back, they first gave the general design flow of the sharding protocol and discussed the key design challenges. Finally, they also discussed several potential research directions for blockchain sharding.

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Originally, sharding was a database partitioning technology that divided very large databases into smaller databases, and the faster and easier to manage part was called data sharding.

The term shard (sharding) represents a small part of the entire collection. Technically speaking, sharding is synonymous with horizontal partitioning, which makes large databases easier to manage.

The core idea of ​​blockchain sharding is to divide the network into smaller committees, each of which processes a disjoint set of transactions (or "shards").

This research document mentioned the key components and challenges faced in blockchain sharding: publicly verifiable randomness is essential for uniformly placing participating nodes into the shard .

The following figure is a comparison of the publicly verifiable randomness of blockchain generation given by researchers:

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The following figure shows the comparison results of the researchers on different sharded blockchain protocols:


In addition to the above sharding schemes, the researchers also briefly mentioned the Monoxide asynchronous consensus sharding scheme and the SSChain sharding scheme.

It is a bit regrettable that the much-watched Ethereum 2.0 fragmentation scheme has not been included.

Second, hard core technical articles of the week

2, 1 Popular Science | Article Interpretation of DC / EP Technical Details

This is a central bank DC / EP technology patent analysis article written by blockchain technology developer Sunrye. In the article, the author analyzes the characteristics of DC / EP, implementation details, specific scene descriptions, and how it also takes into account privacy protection. And regulation.

In general, this is an in-depth popular science article about the central bank's digital currency.

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2.2 Vitalik Long Text: What will happen to the hard core problems that plague cryptocurrencies in five years?

A hardcore long post published by Ethereum co-founder Vitalik Buterin, which lists the issues he thought cryptocurrencies should solve five years ago, and gives progress five years later. These issues are mainly divided into three aspects: cryptography, consensus theory, and economics. Finally, Vitalik also added some new issues that we need to pay attention to today, and he also pointed out that the problems at the base layer will definitely be less and less, and the problems at the application layer have just begun.

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2.3 Chinese Computer Society Report: Research Progress on Key Technologies of Blockchain

This heavyweight paper was co-authored by several professors of the Chinese Computer Society. The article first introduces the current status and challenges of blockchain technology in terms of consensus mechanism, interoperability, security, privacy protection, and supervisability. Then analyze the current research status at home and abroad from cross-chain communication technology, blockchain smart contracts, blockchain security, blockchain supervision and privacy protection, blockchain technology applications, etc., and point out the development trends of related technologies And outlook.

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Interpretation of the Ethereum Yellow Book (4): In-depth understanding of the transaction execution process on Ethereum

Ethereum client contributor Lucas Saldanha dived into Ethereum's transaction verification rules and transaction execution process in this article. If you want to know related knowledge, this article will be a good choice.

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2,5 technology introduction | Zk-stark: Low Degree Testing

This is a Zk-stark hardcore popular science article provided by the researcher of zero-knowledge proof algorithm Jiang Xiaobai. In this article, the author uses an example as a basis to review the Arithmetization process and extend the content to the polynomial LDT process.

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2,6 Layer0 layer capacity expansion, as a CDN of the blockchain

This is a Layer 0 technology solution popular science article from Wei Cao zlf, a thought of blockchain technology researchers.

This article explains the expansion ideas and related technologies of the Bloxroute scheme. This scheme does not require modification of the content of the consensus layer, so it is highly acceptable.

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Technical Progress of Mainstream Blockchain Projects

3.1 Weekly Bitcoin Development Briefing

A weekly Bitcoin development progress report compiled by bitcoinops, covering the main content of Bitcoin Core 0.19, the Lightning Network development update, and the Schnorr / Taproot research update.

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3, 2 Ethereum Istanbul upgrade tentatively December 6, here is everything you want to know

The Ethereum project will usher in the eighth network upgrade at the beginning of next month. The specific time will be the Ethereum block height of 9069000. The EIP and related content involved in this upgrade and what users should do can be found in this article. Find the answer in.

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3, 3 BM latest article: Reconstructing EOSIO resource allocation

Earlier, the EOS project faced a severe shortage of CPU resources due to the EIDOS airdrop, which caused a lot of DApps and related users to suffer. In order to solve this problem, BM proposed a plan to restructure the EOSIO resource allocation last week. It is a newly designed CPU allocation scheme, which is designed to stabilize CPU prices, reduce CPU lease costs, and improve the certainty of using CPU payment costs.

As to whether this scheme is really effective, it remains to be confirmed by the market.

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See you next week ~