博士论文怎么写区块链的,博士论文怎么写区块链论文

写一篇关于区块链的公众号文章，有三个关键词：区块链技术、智能合约、去中心化。

区块链技术是一种新兴的分布式记账技术，它可以构建一个可验证的数据库，可以存储任何形式的数据，包括货币、文件、身份信息等。区块链技术通过构建一个可验证的数据库来记录交易，从而达到安全、可信赖的数据存储效果。它的核心特点是去中心化，不受任何第三方控制，不受任何第三方影响，实现了数据的安全存储，使得数据的安全性大大提高。

智能合约是建立在区块链技术基础上的一种特殊的自动执行的计算机程序，它可以自动执行各种合同，从而实现安全、可信赖的交易。智能合约可以根据合同条款自动执行，从而减少了人工的参与，提高了交易的速度和效率，也可以有效地防止欺诈行为。智能合约的优势在于可以实现自动化执行，只要满足合同条款，就可以自动执行合同，从而减少了人工的参与，提高了交易的效率和安全性。

去中心化是区块链技术的一个核心特征，它不受任何第三方控制，不受任何第三方影响，实现了数据的安全存储，使得数据的安全性大大提高。去中心化的特点是没有中心服务器，每个节点都可以直接与其他节点进行通信，这样可以大大减少网络延迟，提高网络的安全性。此外，去中心化还可以实现数据的安全存储，从而达到安全、可信赖的数据存储效果。

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㈠ Research directions of blockchain

The current main research directions of blockchain focus on several major areas such as consensus mechanism, privacy protection, application, smart contract, and supervision. direction, most of the current papers are based on application as the main research object, conducting application system research in the Internet of Things, medical care, logistics and other supply chains, while other extensive research is based on Bitcoin, currency, Conduct research on public chains such as Ethereum.

㈡ Blockchain Graduation Project Proposal

Background of the project research:

With the development of modern technology and information industry, at this stage, the fourth The second industrial revolution is beginning to take shape, and the world is about to enter a technological era centered on new technologies such as the Internet and artificial intelligence. At the same time, blockchain technology has emerged as the times require and has become a hot topic of concern to many international governments and industries. Blockchain technology has been regarded as the core technology with the greatest potential to trigger the fifth round of disruptive revolution after steam engines, electricity, information and Internet technology. In the past 10 years, with the strong support of the government and policies, the development situation of my country's philanthropy has been relatively optimistic. However, as the scale of charity continues to develop and expand, my country's public welfare undertakings have gradually revealed some shortcomings. The biggest problems existing in traditional public welfare undertakings are insufficient credibility, imperfect internal management of charitable organizations, and high costs. However, many Internet public welfare service companies are currently actively using the new technology of blockchain to solve this problem. Blockchain technology has the characteristics of decentralization, information traceability and non-tampering, openness and transparency, and smart contracts. It can make up for the shortcomings of traditional public welfare undertakings such as opaque information and low management efficiency. Blockchain technology will enter public welfare undertakings and will Bring new development opportunities to the charity industry.

The main content of the research: This topic mainly includes the following three aspects:

[if !supportLists] 1. [endif] Combination of blockchain technology and public welfare Problems that arise and solved.

[if !supportLists] 2. [endif] Make a public welfare query webpage based on blockchain technology

[if !supportLists] 3. [endif] The query system Application issues and explanations

Purpose of the research:

As the scale of my country’s public welfare continues to develop and expand, our shortcomings have also been exposed, including lack of credibility, and charitable organizations There is a lack of management, and the use of blockchain technology can solve this problem. This technology will track and store data and behaviors throughout the donation process, realize the complete disclosure of the public welfare chain, enable donors to effectively supervise, avoid shortcomings such as low efficiency and clear fund flows, control risks for public welfare projects, and improve credibility and transparency of public welfare projects, and promote theDevelopment and progress enhance trust between people. According to the attributes and characteristics of the blockchain system, public welfare enterprises can implement full-cycle tracking, evidence storage and auditing of data and behaviors in the public welfare process, so that all parties involved in public welfare projects can conduct full-process tracking and effective supervision of the project, avoiding Due to the shortcomings of artificially reducing efficiency in public welfare, it provides a rational method for public welfare projects to control risks and judge effects, improve the transparency of public welfare undertakings, and promote the development of public welfare.

Significance of the project research: This project intends to develop an open and transparent system for tracking public welfare donations based on blockchain technology and combined with the actual development of public welfare undertakings in my country. Through in-depth analysis of blockchain technology and charity business, we found that blockchain technology has natural advantages in solving the problem of public welfare transparency. Blockchain technology can be understood as a distributed accounting method that can record all transaction information and ensure that it cannot be tampered with. This determines that wherever justice, fairness, and integrity are required, blockchain has great technology. Room to play. At the same time, the addition of smart contracts directly solves the business problem of earmarked funds.

Eventually, trust between citizens will be enhanced, donation channels will be accelerated, and the development of social donations will be promoted

2. Literature review (current status and development of relevant research at home and abroad Trend)

[if !supportLists] (1) [endif] Current status of foreign blockchain-related industries

China and Europe are gradually occupying the world in blockchain industry policies, and the EU is The European Blockchain Observation Forum has been established in February 2018. Its main responsibilities include: policy determination, industry-university-research linkage, cross-border BaaS

(Blockchain as a Service) service construction, standard open source formulation, etc. Investing 5 million euros in Horizon2020 as a blockchain research and development fund (before December 19, 2018), it is expected that investment in blockchain will reach 340 million euros within three years (2018-2020). In the United States, due to different policies among states, although blockchain is still a craze among American start-ups, the promotion of industrial policy has been slow. The Middle East, led by Di Pai, is leading the trend of blockchain. The government is taking the lead and enterprises are cooperating to explore new technology applications of blockchain. Japan and South Korea are also relatively active in the Asia-Pacific region. Japan is dominated by NTT and the government provides support. South Korea uses finance as an entry point to explore blockchain applications. Isism is also a constant threat to all areas of Chinese society. A comprehensive review of the development status of new media culture in major foreign developed countries, summarizing experiences, and drawing lessons have certain implications for the development of new media culture in China.

[if !supportLists] (2) [endif] Current status of domestic new media research

China’s State Council issued the “Thirteenth Five-Year Plan for National Informatization”, blockchain and big data, artificial intelligence, machine deep learning and other new Technology has become the focus of the country’s layout. The People's Bank of China issued the "Thirteenth Five-Year Plan for the Development of Information Technology in China's Financial Industry", which clearly proposed to actively promote research on the application of new technologies such as blockchain and artificial intelligence, and organize pilot projects for national digital currency. In October 2017, the Ministry of Industry and Information Technology released the "White Paper on China's Blockchain Technology and Application Development", which is the first official guidance document for blockchain.

Governments across the country, especially in coastal areas, have established blockchain experimental sites and research institutes. At present, the governments of Shenzhen, Hangzhou, Guangzhou, Guiyang and other places are actively establishing blockchain development zones and providing special support policies. China Guangzhou officially released 10 Guangzhou blockchain strategies in December 2017 to create a blockchain enterprise technology innovation zone in Huangpu District and Development Zone. In March 2018, the Shenzhen Municipal Economic, Trade and Information Commission issued the "Notice of the Municipal Economic, Trade and Information Commission on Organizing and Implementing the Second Batch of Support Plan for the New Generation Information Technology and Information Security Transformation of Shenzhen's Strategic Emerging Industries in 2018". The district Blockchain is on the list of support directions. This is the fifth local government in China to introduce support policies for blockchain after Guangzhou, Guiyang, and Gehangzhou.

(3) Current status of blockchain in the open source field

Hyperledger (Hyperledger)

Hyperledger (Hyperledger) is developed by the Linux Foundation The open source project to promote blockchain digital technology and transaction verification, launched in 2015, has attracted the participation of many companies including IBM, Intel, Fujitsu, UPS, Cisco, Huawei, Redhat, Oracle, Samsung, Tencent Cloud, Internet Finance, etc. Currently, There are already more than 200 member units, and Bran Behlendorf, founder of the Aache Foundation, serves as the executive director of the ledger project.

The goal of the Hyperledger project is to allow members to work together to build an open platform to meet user cases from many different industries and simplify business processes. Process Ledger has multiple blockchain platform projects, including the Fabric project contributed by BIM, the Sawtooth project contributed by Intel, and Iroha, Burrow, Indy, etc.

The development status of blockchain in the field of standards

ITU-T

ITU-T (International Telecommunication Union standardsChemical Organization) from 2016 to early 2017, SG16 (Study Group), SG17 and SG20 respectively launched research on the overall needs and security of distributed ledgers to attract application research in the Internet of Things. Established three focus groups (Focus Group on Distributed Ledger (FG DLT), Focus Group on Data Processing and Management (FG DPM), and Focus Group on Fiat Digital Currency (FG DFC)), focusing on blockchain and distributed ledger respectively. Technology application and service research, establishing a trustworthy Internet of Things and smart city data management framework based on blockchain, and carrying out standardization work on blockchain applications based on digital currency. Huawei serves as the chairman of the Architecture Group of the Focus Group on Distributed Ledger (FG DLT) and the Blockchain Group of the Focus Group on Data Processing and Management (FGDPM).

Two committees of CCSA (China Communications Standards Association) have established subgroups and projects respectively:

CCSA TC10 (Internet of Things Technical Working Committee) Established in October 2017, the Internet of Things Blockchain Subgroup: Responsible for the application research and standardization of blockchain technology in the Internet of Things and its covered areas such as smart cities, Internet of Vehicles, edge computing, Internet of Things big data, Internet of Things industry applications, logistics and intelligent manufacturing, and is led by China China Unicom technical experts serve as team leaders, and Huawei technical experts serve as deputy team leaders.

The Blockchain and Big Data Working Group under CCSA TC1 (Internet and Application Technology Working Committee) completed two blockchain industry standards: "Blockchain: Part 1 Overall Technical Requirements for Blockchain ” and “Blockchain: Part 2 Evaluation Indicators and Evaluation Methods”, in which Huawei actively participated.

JPEG

During the 78th JPEG Conference in February 2018, the JPEG Committee organized a special session on blockchain and distributed ledger technology and their impact on the JPEG standard. Meeting. Taking into account the potential impact of technologies such as blockchain and distributed ledgers on future multimedia, the committee decided to establish an ad hoc group to explore use cases and standardization needs related to blockchain technology in a multimedia environment, with a focus on imaging and multimedia applications. standardization work.

IETF

The "Decentralized Internet Infrastructure ProposedRG

(Research Group) was established at the IETF99 meeting in June 2017, planning to study the blockchain architecture. and corresponding standards. In 2018, IETF will likely pay more attention to the implementation and development of blockchain interconnection standards on the blockchain.



3. The proposed research methods (plans, technical routes, etc.) and feasibility demonstration

This topic mainly studies the application of blockchain technology to charitable donations. Research methods:

1. Use literature methods to collect relevant theories, and use information retrieval, screening and other methods to collect literature materials and related theories. Understand the current status of blockchain technology and master blockchain technology. Decentralized technology.

2. Combine the technology with public welfare by combining theory and practice. Complete improvements to the system.

3. Use the method of comparative analysis to discuss the current development status of new media operations from both domestic and foreign aspects, as well as existing problems in the development of my country's new media operation models, and look forward to the development prospects of this technology field.

Feasibility demonstration:

1. Technical feasibility. The research goals involved in this topic already have considerable theoretical foundations at home and abroad. Through literature survey, we can learn about actual, reliable and useful information data, and the actual requirements are not difficult.

2. Economic feasibility. The research on this topic can be done by accessing literature and materials through the Internet and libraries. It is convenient and feasible and does not require a lot of economic consumption. Therefore, from an economic point of view, it is completely feasible.

3. Operational feasibility. This topic requires the combination of blockchain technology and public welfare, especially the tracing of these applications. A comprehensive analysis of the graduation project system on this topic can be achieved through the analysis of both Study the literature and study the existing information documents, use the data you collected to organize and analyze, apply what you have learned, and complete this project completely. From an operability point of view, it is completely feasible.

4. Expected results (or expected results)

1. Through research on the data, clarify the relevant concepts of blockchain technology, skillfully use dapp, and create a web page.

2. Through distributed applications, creating a system that allows the public to quickly browse and understand the public welfare process will increase convenience for the further development of my country's public welfare undertakings.

3. I hope that I can continue to learn and make progress from the process of writing this paper. Being able to master the relevant knowledge of blockchain will be helpful to your future career.

iii The hierarchical structure of the blockchain (what is Layer0/1/2 of the blockchain)

The hierarchical structure is the basis for the data processing and operation of the blockchain.

In order to find a scalability solution for the blockchain, the blockchain referred to in the academic research field (usually in papers) is divided into three layers: Layer0, Layer1 and Layer2.

Generally, the blockchain system is mainly divided into six layers: application layer, incentive layer, consensus layer, network layer and data layer, which are mainly reflected in the early Bitcoin system. With the emergence of smart contracts, a contract layer was added between the application layer and the incentive layer, mainly reflected in the Ethereum system.

The content of each layer is shown in the figure above, but the technologies used in different specific systems may be different. For example, the consensus layer mainly completes the consensus between nodes, except for the workload proof. The mechanism (Proof of Work) also includes the Proof of Stake mechanism (Proof of Stake) and the Byzantine Fault Tolerance mechanism (BFT).

The data layer, network layer, and consensus layer constitute The underlying foundation of the blockchain hierarchy is also the three essential elements of the blockchain. Without any one of them, it cannot be called a true blockchain technology.

Blockchain hierarchical structure correspondence The comparison between the OSI system 7-layer model and the TCP/IP 4-layer model is shown in the figure below.

If we focus on the four layers of TCP/IP, especially the "application layer" above, We will see that it is possible that the blockchain separates the application layer that was originally focused only on information transmission into a new layer dedicated to value transfer. Therefore, we can think that the four layers of TCP/IP are split into five layers , regard the blockchain as a layer of TCP/IP: the value layer.

It is generally believed that Bitcoin, Ethereum, and EOS are representatives of blockchain 1.0, 2.0, and 3.0. If you look at them The layering is also very interesting:

From Bitcoin to Ethereum, the contract layer was added. From Ethereum to EOS, because of the use of DPOS, the incentive layer was actually merged into the consensus layer. And EOS added Two layers: ① Tool layer to let theIt is easier to develop applications; ② Ecological layer, it is positioned as an open source software, so others can use its open source software to build industry chains and domain chains.

Xu Zhong and Zou Chuanwei wrote a central bank working paper, discussing blockchain from an economics perspective and trying to provide a Token paradigm. Among them, they actually gave a layered model, this time it is internal and external layering: the inner layer is consensus, which is divided into: Token, smart contract, consensus algorithm; at the boundary of consensus and blockchain, is the blockchain Other information within; outside the boundaries of the blockchain, is the Internet and the physical world.

In order to improve performance, some systems actually layer their distributed networks. That is, not all nodes are equal.
For example, the following is the layering of EOS.

In order to make blockchain useful, some people are discussing it from other perspectives. Zhu Feng of ENChain.Asia proposed the "Seven-layer Self-Organizing Business Model" in the BAO white paper. This model was quoted in the "Model and Practice of Token Economy" (0.2) report as the "Seven-layer Self-Organizing Business Model" Model".

However, it should be noted that the "incentive layer" here is similar to the incentive layer we usually call blockchain, but it is different. When we discussed the incentive layer before, we often discussed it from the perspective of the native tokens of the public chain, while the incentive layer here is discussed at the pass level.

In a report "Construction and Analysis of the Four-Layer Application Model of Blockchain" in December 2018, Huobi Research Institute gave a four-layer application model, which is very interesting: < br />
References:
1. Ten years of blockchain: various layers
http://www.360doc.com/content/18/1211/10/ 53358875_800866301.shtml
2. How much do you know about the six hierarchical structures of blockchain? - Zhihu
https://zhuanlan.hu.com/p/98126049
3. Introduction to the six hierarchical structures of blockchain - Blockchain - Electronic Enthusiast Network
http ://www.elecfans.com/blockchain/1138839.html

㈣ Can you cite literature at the end of a blockchain paper?

It is very common to cite literature at the end of a paper. This approach can be adopted whether it is a blockchain paper or other types of papers. When citing literature, you need to pay attention to the following aspects:

Citation format: When citing literature at the end of the paper, all literature materials need to be formatted according to the citation format specifications used. Commonly used citation formats include APA, MLA, Chicago, etc., which need to be formatted according to the title, author, publisher and other elements.

Citation content: When citing documents, you should only cite materials related to the topic of the paper and avoid citing content that is irrelevant to the topic. In addition, the quoted content needs to be consistent with the text and content of the paper, maintaining the logical relationship and coherence of the paper.

Number of citations: When citing references at the end of your paper, you should not cite too many references. The number of cited documents should be appropriately controlled based on actual needs to avoid citing too many irrelevant documents.

When citing literature at the end of a blockchain paper, you can refer to some typical blockchain papers or books and include them in the reference list. This helps to end with a hook, leads to a new research direction, and can also provide a more sufficient theoretical basis for analyzing the theme of the paper.

The following are some recommended papers and books about blockchain:

Nick Szabo: "Blockchain Applications: How It Works and Important Areas", O' Reilly Media, 2017

Anton Anderson and Don Tapscott: "The Blockchain Revolution: How It's Transforming Trade, Finance, Companies, and Our Future", Publisher: Portfolio , 2016

Jordan Dokanoski and Biseta Narayanan: "Blockchain Identification and Interpretation: Techniques, Tools, and Applications (Identification and Resolution)", Manning Publications, 2018

A.B. Călin, A. Turcanu, F. Drăgănescu: "Blockchain - A Primer", Publisher: Universe, 2019

Zulip Bank Group EconomicsResearch team: "Blockchain: Diverse Applications for Creating Value", 2017.

These books and papers cover the application of blockchain technology in finance, trade, smart contracts, etc., as well as the essence and future development trends of blockchain technology. Reading these materials can help you gain an in-depth understanding of blockchain technology and its applications, master related technologies and concepts, and provide valuable reference materials for blockchain-related research and paper writing.

㈤ Re-understanding the blockchain: Enlightenments brought by more than 1,550 application cases

Author: Ran Wei

(This article is excerpted from "2021 Global Area Blockchain Application Market Report")

When we talk about blockchain, anyone who knows something about blockchain can more or less express some of their own opinions on related topics. . For example: from the perspective of technical system, blockchain is a new application of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm; from the perspective of functional attributes, blockchain is decentralized, non-tamperable, and full-process. Features such as leaving traces, traceability, collective maintenance, openness and transparency.

Looking back at the history of blockchain, there is no way around Bitcoin. On January 3, 2009, the Bitcoin genesis block with serial number 0 was born. A few days later, on January 9, 2009, Bitcoin block number 1 was born. When two blocks are connected, the blockchain is "born."

The inventor of Bitcoin, who goes by the pseudonym "Satoshi Nakamoto", may find it difficult to imagine: In the past 12 years, with Bitcoin as the center, a huge "cryptocurrency family" has spread all over the world. The financial market set off a "big wave" that continues to this day. During this period, innovation and risks related to cryptocurrency are intertwined, progress and bubbles coexist, and pursuit and criticism coexist, and it drives government departments of various countries to continuously improve the monetary and financial systems, social governance and supervision systems.

At the same time, the blockchain that accompanies Bitcoin is also evolving rapidly, and has long gone beyond the scope of "Bitcoin's underlying technology" and has been applied to every corner of social and economic development.

So, what mechanism does blockchain work through? What are its advantages compared to traditional technologies and models? What is its application effect? In the "2021 Global Blockchain Application Market Report" jointly released by Capital Lab and Yuanwang Think Tank, we tried to provide a certain basis for the above issues through research on more than 1,550 application cases around the world in 2020 and the first quarter of 2021. Empirical answer. At the same time, based on the study of these cases, we can establish a new understanding of blockchain: blockchain is trust, blockchain is sharing, blockchain is transaction, blockchain is substitution, and blockchain is efficiency.

In the Bitcoin creation paper "Bitcoin: A Peer-to-Peer Electronic Currency System", "Satoshi Nakamoto" repeatedly emphasized that Bitcoin has the characteristics of not relying on a "trusted third party", that is, the characteristics of "decentralization".

On the other hand, the underlying technology of Bitcoin, the blockchain, is precisely designed for "trust." In other words, reshaping "trust" in the digital age is the most basic function of the blockchain, but this trust has been transformed from trust between people and legal entities to trust between machines and machines. Trust between blocks and between nodes. Interestingly, the subsequent “smart contract” function has further strengthened this trust through its integration with the blockchain.

Identity coding and authentication are the first steps to achieve the above-mentioned trust mechanism, and the distributed identity (Decentralized Identity, DID) system is the core of it. With DID applications, everyone from individuals to organizations to IoT devices, from physical items to virtual products, can be given digital "identities" and achieve trusted interactions. It is precisely because of this that blockchain-based certificate storage, empowerment, verification, circulation, and transactions can be realized, and only then can blockchain be implemented in various industries.

Application cases from around the world show that new trust mechanisms provide new rules and motivation for social and economic operations:

l China is comprehensively promoting blockchain electronic certificates Applications such as "one fish, one code", "one fruit, one code", "one tea, one code" and other applications are driving the global Anti-counterfeiting traceability of agricultural products and upgrading of food safety systems;

l Through the combination of blockchain, big data, and artificial intelligence, the credit "portrait" of an enterprise is more accurate and can be obtained faster and more accurately. Lower-cost financing services;

l Charitable charity organizations have put charity funds "on the chain" to form a more transparent and standardized charity tracking and management system;

l Relevant cities in China have launched a blockchain-based gas cylinder product traceability management system, and the credibility of the source of gas cylinder file information and the level of gas cylinder safety management have been greatly improved;

l Germany is developing its distributed energy resources Assets establishes a digital registration system based on identity authentication to promote the development and trading of renewable energy and cope with the arrival of the digital energy era...

Among the three types of blockchains (public chain, alliance chain, private chain), alliance chain has been the most widely used. In addition to considerations of technical performance, operational efficiency, operability, expected results, etc., this is mainly because all parties in the alliance already have a certain foundation of trust. This also shows from another perspective: In blockchain applications that transcend cryptocurrencies such as Bitcoin, "multi-centralization" rather than complete "decentralization" is a more realistic onechoose.

In addition, it is undeniable that unlike the proof-of-work mechanism that Bitcoin “mining” relies on, the blockchain cannot completely ensure the integrity of the on-chain data from the source in the actual application process. Authenticity. In other words, a certain alliance member or node may provide false data intentionally or unintentionally. However, with the help of blockchain's non-tampering, traceability, multi-party consensus and other characteristics, the alliance can identify counterfeiting behavior and impose corresponding punishments, such as "kicking" the counterfeiting members from the nodes. Therefore, in a sense, blockchain-based trust largely establishes alliance members’ awe for the authenticity of data and deters data fraud.

If "trust" is the foundation of blockchain applications, data sharing is the core of blockchain applications. Without data sharing, there will be no cooperation, and the practical application of blockchain will be impossible.

l The State Administration of Foreign Exchange's "Cross-border Financial Blockchain Service Platform" pilot has been fully launched, promoting foreign trade exports through information exchange between foreign exchange bureaus, taxation, banks and enterprise-related market entities. Business development;

l The "Insurance/Claims Alliance Chain" jointly established by 11 insurance companies in Taiwan has been put into operation, and each company has achieved "single application and common documents" on this platform;

l Blockchain platforms such as Contour and TradeLens are reshaping the global supply chain and providing impetus for the digital transformation of international trade through data collaboration among enterprises, financial institutions, shipping companies, terminals, customs and other institutions... .

l In China, through data collaboration, various government departments have realized "one data, one source, one source for multiple uses, one network, and full network operation";

l Through The "Judicial Chain" platform allows all types of electronic evidence to be seamlessly connected with judicial institutions such as notarization, arbitration, judicial appraisal, and courts, which improves the efficiency of the judicial system while reducing costs;

l Targeting grassroots nationwide The court's "cross-domain collaboration mechanism for trial auxiliary matters" can realize "cross-domain service and cross-domain evidence collection" between courts in different regions, effectively improving the efficiency of trial auxiliary matters and trial quality and efficiency, and reducing judicial operation costs... ….

l China's "Guangdong-Hong Kong-Macao Greater Bay Area Combination Port" project was officially launched, which can support the interconnection and interoperability of trade parties among the five major customs jurisdictions of the Greater Bay Area and become the first connected port in the Greater Bay Area , customs, logistics, enterprise, finance and other trade processes, interconnected and shared blockchain network;

l Japan's KDDI Telecom, Hitachi, Kansai Electric Power, Sekisui Construction and other large enterprises have established blocks Chain Alliance NEXCHAIN ​​to form a cross-industry real estate information sharing and management model and promote cross-industry innovation;

l FranceGroupe Renault has completed testing of its blockchain project “XCEED” for sharing compliance information between parts suppliers and car manufacturers and simplifying compliance certification…

Although the above application cases in finance, government affairs and various industries are only a few typical cases, they are enough to illustrate that: on the one hand, data sharing is an inherent requirement of blockchain applications. In terms of specific implementation, everything must start from breaking "data islands" and "information asymmetry"; on the other hand, the application practice of blockchain has in turn promoted cross-level, cross-department, cross-industry, cross-region, and cross- Data sharing and unprecedented cooperation across national borders.

It can also be seen from the above cases that based on the transparency, security, trustworthiness and other characteristics of the blockchain, data sharing allows cooperation that originally seemed impossible to be achieved, and more Open innovation results; data sharing can effectively improve the operating efficiency of business systems, financial systems and social governance systems; various organizations promote their own organizational changes and process changes while sharing and cooperating with external institutions.

Based on trust and sharing, "transaction" is the most intuitive and deepest manifestation of the value of blockchain applications. Currently, blockchain is opening a new chapter in the transformation of transaction models in various industries around the world.

From a functional architecture point of view, blockchain-based transactions are by no means just a change in the transaction process, but integrate the unique functions of the blockchain, which are the key to anti-counterfeiting traceability, supply and demand docking, and warehousing. Integrated integration of blockchain applications such as logistics, payment/settlement, supply chain financing, insurance, and network security.

From the perspective of application form, blockchain-based transactions transcend the traditional concept of product or service transactions and represent the realization of the value of a wider range of data in circulation.

From the perspective of application scenarios, transactions based on blockchain involve the upgrading of the physical industry, the digital advancement of the financial industry, and the innovative application of the "token economy".

In the physical industry, take the application of agricultural blockchain as an example: on the one hand, supply chain traceability based on blockchain has become an important barrier to food safety; but on the other hand, for growers or For farmers, the supply chain traceability function is far from enough. How to help them expand the sales of agricultural products and obtain more income as much as possible is the "hard truth" for blockchain technology to continue to promote agricultural development. In other industries, the same applies.

Against the above background, new trading platforms in the global physical industry continue to emerge:

l The Indian government uses blockchain platforms to help farmers in remote areas sell agricultural products to reduce the While reducing intermediate fees, obtain higher income;

l The Swiss company Cerealia builds a blockchain-based agricultural product trading and financing platform to promote global emerging market countries.export of agricultural products;

l The world's largest independent refined sugar producer, Al Khaleej Sugar Company of the United Arab Emirates, launched DigitalSugar.io, a blockchain-based sugar product trading platform, to realize spot-based international raw sugar. Transaction;

l Jiangxi Ganzhou has launched an international timber electronic trading platform based on the blockchain, which will manage the entire process of timber transactions on the chain, and will provide regulatory cloud warehouses, logistics, finance, and insurance for the timber market. and other full industry chain services;

l Shandong Province launched the Shandong Internet Traditional Chinese Medicine Trading Platform, which will realize online integrated services of quality control, trading, payment, settlement and supervision through blockchain and other technologies;

l Weitang Town, Xiangcheng District, Suzhou has launched a blockchain-based pearl online trading platform, which will store the core parameters and test reports of pearls on the chain, and will also add supply chain management, trade finance, and smart contracts. , payment settlement, incentive mechanism and other functions;

l Honeywell launched GoDirect Trade, an online trading platform for new and second-hand aircraft parts, to provide guidance for large manufacturers on how to apply blockchain to their parts. Parts Trading and Circulation provides a valuable reference….

In the financial industry, blockchain is promoting the digital advancement of financial transaction business in aspects such as securities trading, asset securitization, trade financing, and cross-border settlement:

l The Australian National Stock Exchange has launched ClearPay, a digital securities trading platform based on distributed ledger technology, which can provide multi-currency, real-time DVP settlement on the same day and will replace the original exchange settlement system;

l Switzerland The company Finka has launched a related securitization token investment platform based on livestock from organic pastures in Bolivia to promote the development of the local livestock industry;

l The American company Securitize has established a Japanese real estate investment platform based on digital securities , aiming to revitalize idle real estate in rural Japan and enhance the vitality of the rural economy;

l China Postal Savings Bank and China Construction Bank completed the first cross-blockchain platform forfaiting transaction, Hua Xia Bank Kunming Branch’s first Realize forfaiting resale business in the secondary market;

l Nanjing Iron and Steel completed blockchain-based iron ore transactions with Rio Tinto of Australia and Vale of Brazil respectively;
< br /> l Baosteel Co., Ltd. and Australia's Rio Tinto completed the first blockchain-based RMB cross-border settlement transaction...

Of course, while blockchain promotes the advancement of financial transaction business, dark sides such as hype, scams, money laundering, and cyber attacks related to blockchain and cryptocurrency continue to follow. How to continue to promote financial innovation while alsoEfficient risk prevention and control, as well as a strong crackdown on illegal crimes, are important issues that require long-term response. From a global perspective, China has responded with clear attitudes, strict measures, and effective measures in this regard.

The transaction changes realized by the blockchain in the real industry and financial industry are only the initial stage of the blockchain changing the traditional transaction method. The "Token Economy" is the blockchain "transaction" A higher level of functionality.

Under the framework of the "token economy", from electronic certificates to skill certificates, from credit records to public welfare activity participation records, from social media tracks to carbon emission reduction actions, when various data become When an encrypted digital proof of rights is circulated and exchangeable, it is given the function of "token".

Regardless of the investment/speculation craze of "Non-Fungible Token (NFT)", we can already see many early applications of "token economy" around the world:

l The HotCity project supported by the Austrian government uses a crowdsourcing model combined with blockchain and gamification tokens to encourage residents to submit heating waste heat hotspots to meet urban heating needs more efficiently;< br />
l Ford establishes "Green Miles" for commercial and municipal fleets using hybrid vehicles to help improve urban air quality;

l Weibin District, Xinxiang City, Henan Province, in its In the blockchain industrial park project, tokens are issued based on the points system for merchants and enterprises to establish a new commercial service platform;

l Chengdu released a blockchain-based community governance product "Chain Dynamic Community", Residents can earn "time bank" points on the platform through volunteer services and other activities, and exchange them for benefits and discounts provided by community merchants;

l Global non-profit organization "Mobile Open Blockchain Plan" The Electric Vehicle Charging Network Working Group (EVGI) launches a global standard system for decentralized vehicle charging technology, covering the Tokenized Carbon Credit (TCC) scenario;

l Blockchain reward platform MiL. k cooperates with a Korean retailer to provide blockchain-based points management services to its members. Members can convert existing points into local MLK tokens through the MiL.k platform, or exchange them into other third-party points...

As can be seen from the above cases and more, the "token economy" has several distinctive features:

The "token economy" gives assets to a wider range of data Attributes and tradable attributes, and through cross-domain and cross-platform mutual trust and circulation, can improve the operating efficiency of the entire social and economic system;

"Token economy" is a newThe process of value creation and realization does not necessarily use currency directly as the medium of exchange, but is more reflected in the exchange, mutual benefit and reconfiguration of various elements and resources;

"Token economy" is often related to The combination of incentive mechanisms will effectively reshape the social value system and social credit system by motivating "good people and good deeds", "good companies" and "good institutions".

Generally speaking, the "token economy" will spawn new production factors, reshape production relations, and greatly liberate social productivity; the "token economy" represents the direction of the "information Internet" The evolution of the "Internet of Value" indicates the most exciting future of the digital economy; the "token economy" based on the blockchain has begun to take shape and has begun to bring changes to economic operations, social governance, and everyone's lifestyle. Continuously visible change. All types of institutions and individuals should be mentally and physically prepared for this change.

Like other new technologies, in the process of application and popularization, blockchain continues to produce substitution effects in terms of platforms, media, models, methods, etc.: physical documents are replaced by electronic documents, and credit records are replaced by electronic documents. Passes are replaced, manual review is replaced by data verification, and the city management platform is replaced by the "city brain"...

Such substitutions have become the norm:

l Argentina’s central bank has begun a proof-of-concept for a new blockchain clearing system, which may replace the existing clearing system;< br />
l Korea Minting and Security Printing Corporation (KOMSCO) expanded its blockchain digital gift certificate business to replace paper gift certificates and achieved record revenue despite a sharp decline in the issuance of banknotes and coins. Improvement;

l Courts across China have begun to use blockchain electronic seals to replace traditional paper seals in the enforcement of real estate seizures;

l The Shanghai court system is using artificial intelligence , the adoption of new technologies such as blockchain, and explore the use of digital court trial records to replace manual court trial transcripts;

l The Japanese company SUSMED launched a "Clinical Data Monitoring System Demonstration Using Blockchain Technology" pilot, indicating that the drug Or the necessary monitoring process in clinical trials of medical equipment can be replaced by a blockchain system;

l Alipay and Wukong Car Rental have cooperated to launch a "face-swiping" car rental service, which uses blockchain technology and credit-free security mode, tourists can rent a car by simply "swiping their face" and return the vehicle through mobile phone operations;

l Under the new crown epidemic, local governments in China have intensively launched "non-face-to-face" vehicles that combine blockchain technology ", no contact, zero errands" government services have replaced traditional offline service methods and provided smooth progress in remote bidding, "cloud" customs clearance, financial support, and resumption of work and production during the epidemic.A strong guarantee...

In addition, we can also see that through the use of blockchain technology, various enterprise-level services are also realizing substitution and evolution: from paper contracts to electronic contracts, to program-based, Blockchain contracts that can automatically execute smart contracts. Blockchain is pushing contract signing into the era of "chain signing"; from offline human resources companies to online human resources platforms to the blockchain-based human resources market , global human resources services have experienced continuous changes from the 1.0 era to the 2.0 era, and then to the 3.0 era.

Generally speaking, when the blockchain "invades" various industries, it will "mercilessly" delete all unnecessary links and processes, all unnecessary manual operations, and accelerate the The era of paperless, unmanned and automated is coming.

In the process of our analysis of more than 1,550 blockchain application cases around the world, words like "improve", "accelerate", "shorten", "lower", "reduce", "save", " Words such as "save" appear frequently in front of our eyes. These words show that the improvement of efficiency is the common pursuit of all parties involved in blockchain applications and is also the most direct result of the substitution effect of blockchain.

Numerous application practices are contributing to this:

l Kenyan company Shamba Records provides blockchain traceability, transaction and financing services to farmers in the country, currently covering more than 6,000 Small farmers and helped them increase their income by at least 40%;

l TradeWaltz, a blockchain trading platform invested by NTT DATA, Mitsubishi and other companies, completed a trial run, and the results showed that the platform can reduce traditional 50% of the workload of the trade process;

l Walmart Canada has significantly reduced invoice disputes with carriers by 97% through the application of the DL Freight blockchain platform;

l The State Grid Corporation of China’s power transaction certificate traceability inquiry platform has been put into operation, automating the entire authenticity review process for registered users and saving 99% of trusted manual review time;

l COSCO Shipping Lines and Shandong Port Group Qingdao Port have cooperated to launch a blockchain paperless import and delivery model, which can save customers nearly 24 hours on average per container;

l Taizhou, Zhejiang uses "materials" The "Internet + Blockchain" recycling system solves the problem of marine pollution control. Compared with traditional processing methods, this recycling system can save 94% of labor costs and 84% of operating costs...

In summary, through the joint action of trust mechanism, sharing mechanism and transaction mechanism, blockchain has formed an obvious substitution effect, improved the operational efficiency of finance, government affairs and various industries, and will continuous forminto systemic change. This change is reshaping the relationship between people and machines, people and society, and people and the environment, and clearly points to three ultimate goals: efficiency, well-being, and environmental protection.

㈥ The significance of digital identity in the blockchain (with an excellent blockchain article that triggers thinking)

As the infrastructure and connector of the current Internet, WeChat has all the value They are all based on "connection", the connection between people, the connection between people and money, the connection between people and things, and now the connection between people and things (scan the QR code in the Mobike mini program to ride a bike), but all "connections" are There is a premise that I trust WeChat, I trust Tencent, I trust the legal system’s regulation of the Internet, and I trust that everyone around me is using WeChat. The root cause of this trust is trust in centralization, trust in companies with good reputations, trust in institutions, and the legal system , the trust of the community.

Nowadays, the blockchain seems to be able to turn each node in the blockchain network into a "WeChat". In order to form this kind of decentralized trust, we need to define a unique identifier for the node "WeChat". Trust the digital identity. This digital identity is not only the private key for managing your own digital assets in the blockchain network, but also allows this digital identity to ultimately serve real life and implement application scenarios. Therefore, it also needs to be endowed with prerequisites. The credit label of the legal system, institutions and communities.

The future world is distributed, and each node is verifiable and trustworthy. Whether placed in the blockchain or in the real world, each node becomes a "WeChat" trusted by all of us. , and at the same time, we ourselves can also become “WeChat” trusted by others.

Attachment: The significance of digital identity for blockchain - Liu Yongxin (NEL)
1. Ship of Theseus - How to define yourself

In life, we often use Regarding identity, we often introduce ourselves to others. Sometimes we give out our business cards, and sometimes we show our ID cards. However, many people may not know what the meaning of identity is and how to define it.

There is a famous thought experiment called "The Ship of Theseus". The Ship of Theseus can sail uninterruptedly on the sea for hundreds of years. If a plank rots, a new plank will be replaced until there is a plank. One day, all the planks on the ship were not the original planks. So is this ship still the original ship of Theseus?

The human body is like the ship of Theseus. Cells are always undergoing metabolism. So all the cells have been renewed. Are you still the same person? What if your thoughts and personality also change?

Therefore, how to define yourself does not seem to be a simple matter.

2. Identities in life

In life, we have many identities. For example, in a company, you have your own position. In a family, you may be a husband or a wife. Or kids, yes.For the bank, you are its customer; for your house, you are its owner and the tenant's landlord; for your car, you are the owner.

So we found that in different scenarios, you have different identities, and different identities usually correspond to different objects. For a bank, what it cares about is whether you are its customer. It doesn’t matter what role you play in the family. For a car, as long as you have its key, you can start it. Whether you are the landlord Don't care.

3. Define identity

Based on the previous discussion, I try to define identity:

Identity is the identifier of relationship,

Relationship is Bidirectional,

A relationship represents the rights and obligations between the parties.

So you have different relationships with different objects, you have different rights and obligations, and you have different identities.

For the country, you have citizenship, which is usually represented by an ID card. Citizenship means that you have the obligation to pay taxes and that you have the right to vote in elections. To the bank, you are its customer, representing your deposits and liabilities with it. For blockchain, you master the private key, which means you own the assets controlled by the private key, and the private key is your identity.

Therefore, we should not abandon the object and explore identity. What is important is not who you are, but who you are in the eyes of others.

In the process of using identity, there are two processes: authentication and verification. For example, after a Chinese is born, he has to go to the police station to register his household registration. This is the authentication process. After that, presenting his ID card is the verification process. Registration and login of accounts on the Internet are identity authentication and verification processes. The certification and verification of asset ownership in the blockchain is achieved through a consensus algorithm, which can be simply considered to be 51% voting approval.

4. Trusted data

Satoshi Nakamoto wrote a sentence in Bitcoin’s genesis block: “The Times 03/Jan/2009 Chancellor on brink of second lout for banks", this sentence was the front page headline of The Times that day, meaning "the Prime Minister saved the banks from the brink for the second time".

Many people believe that this sentence proves that The Times must have published this article that day, reflecting the existence proof capability of the blockchain.

However, the blockchain can only ensure that the written data cannot be tampered with, but cannot guarantee the authenticity of the data. The reason why we believe that this newspaper article must exist is because it was Satoshi Nakamoto who wrote the blockchain, and the authenticity of the data is guaranteed by Satoshi Nakamoto’s credibility.

In fact, the authenticity of data is generated in two ways:

Decentralized method, or 51% democratic voting. For example, the authenticity of Bitcoin transaction data is actually guaranteed through 51% computing power voting. When off-chain data is uploaded to the chain, manual voting can also be used Ways to ensure the authenticity of data, such as the decentralized prediction platform Augur.

However, not all consensus can be reached through majority rule.

For example, whether a work of art is authentic or fake must be authenticated by experts, but cannot be determined by the majority. The credibility of the appraisal results is guaranteed by the credit of experts. Whether a person is Chinese or not is verified by the police station when registering for residence, not by a vote of all Chinese people. Therefore, for specific scenarios, sometimes it is necessary to confirm the authenticity of the event through recognized authorities.

Normally, data native to the chain, such as token distribution, transactions and other data, can be easily reached consensus through a minority-subject-majority voting mechanism. However, when off-chain data is uploaded to the chain, its data Authenticity relies on the identity and reputation endorsement of the person on the chain, and sometimes legal means are needed to deter fraud through accountability mechanisms.

5. Trusted data uploading to the chain

Therefore, for the uploading of off-chain data, the authenticity of the data can be completed through the vote of a minority subject to the majority or the credibility endorsement of an authoritative identity.

The basic process of uploading trusted data to the chain should be as follows:

First, you need to have a digital identity. The authentication of this identity may be generated by 51% of the votes. It may also be through authoritative certification.

Then when the data is uploaded to the chain, identity information needs to be attached.

After obtaining the data, the data user verifies the identity information, and then determines the credibility of the data based on the verification results.

6. Identity management

When we use network applications, we need to register and log in to our account. Sometimes, for convenience, we will use third-party applications to register and log in. This Although the identity hosting method provides convenience, third-party applications can actually log in to the application without our authorization, perform operations, and obtain personal data.

So ideally, we want to be able to balance convenience and security. We want to be able to log in to different applications through the same account and be completely controlled by ourselves.

Digital identities can be roughly divided into three categories:

Digital sovereign identities, in the form of CA certificates, EIDs and other solutions in China, must meet the requirements of the government.Government supervision, compatibility with national laws, and sovereign identity must be known.

Digital network identity, that is, the login account of various APPs

Digital asset identity, that is, the address and private key of various blockchain assets

Digital identity Management applications should be compatible with these identities and be able to implement identity authentication, verification, logout, loss and retrieval, etc.

There should also be a data management platform to realize data storage and permission management.

The blockchain platform can be used as a data storage platform to store data fingerprints, reading and writing records, etc. Smart contracts can realize identity verification and avoid redundant information leakage through encryption technology. Multi-signature enables key retrieval. At the same time, the blockchain is also a registration platform for digital assets.

On this basis, a variety of application scenarios can be realized, such as: APP login, electronic contract signing, supply chain, copyright protection, and asset digitization.

When digital identity and blockchain are combined, coupled with a data management platform, the needs of the alliance chain can be realized, such as the KYC alliance between banks. The essence of the alliance chain is identity-based data mutual trust. It does not matter whether it is a separate chain.

Once blockchain assets are associated with sovereign identities, they can meet government regulatory needs, and regulatory strategies that meet regulatory needs can be added at the application layer.

Therefore, if blockchain is to be applied on a large scale in the future, it is necessary to solve the problem of digital identity. Digital identity is the bridge between the on-chain and off-chain, and the bridge between blockchain and compliance supervision.

As more and more applications and assets are built on the blockchain, big data analysis becomes possible because of the unified identity. Therefore, the combination of big data and blockchain, It’s also inseparable from digital identity.

㈦ Blockchain can improve the transparency and flexibility of the supply chain

Today’s market competition has become increasingly dynamic and demanding, resulting in a challenging competitive environment. To adapt to this dynamic environment, supply chains increasingly rely on collaboration, integration, flexibility and trust among those taking over. Therefore, new technology applications are becoming increasingly important in supply chains.

In order to improve supply chain process control, Maoqiu Technology believes that modern professional applications must be implemented. Blockchain technology has become an essential part of today’s competitive environment. Companies should invest in blockchain technology to quickly respond to changing market conditions and demands in today’s dynamic business environment.

According to a paper report released by MDPI, blockchain solves the two main problems of traceability and transaction irreversibility in the supply chain, thereby effectively improving the transparency of the supply chain. Transparency, a priority for all stakeholders in the supply chain, ensures that productsInformation can be viewed and obtained in a timely manner, and there will be corresponding losses caused by information delay.

Supply chain transparency is primarily based on information about the movement of products along the supply chain. If companies are to maintain the ability to proactively communicate with stakeholders to gain visibility and traceability of supply chain operations, they can ensure the visibility and Accessibility.

In the above manner, stakeholder feedback can be included in the blockchain to improve the performance capabilities of the supply chain. In addition, the history of a product can be tracked throughout the supply chain, and a clear picture of current activity can be displayed. Companies can confront environmental or social issues through transparency by articulating core values ​​to reduce uncertainty in public markets.

Many stakeholders have high hopes for blockchain because of its capabilities such as real-time information sharing, security, immutability, and transparency. With its proof-of-work and distributed database structure, blockchain can increase supply chain transparency while using real-time distributed data sharing to enable stakeholders to identify data related to product quality, location, transactions and procedures.

These capabilities of blockchain enable product tracking, allow for comprehensive product verification and product authorization throughout the transaction process, and provide end-to-end auditing based on permissions across the organization. Blockchain reduces the opportunistic behavior of trading partners in terms of information tampering, corruption, fraud, etc.

Therefore, blockchain provides transparency in transactions between trading partners, thus increasing trust, and blockchain strengthens the relationship between suppliers, customers, outsourcing, The relationships between 3PLs and subcontractors make the supply chain more efficient and transparent.

Blockchain technology can help build trust and reputation by bringing transparency to supply chains. Large-scale blockchain solutions have the ability to completely redesign reputation management and detect fraud across entire networks. Blockchain consensus provides a solid foundation for the unification of opinions and the ability to achieve higher transparency. Establishing a decentralized supply chain based on blockchain technology instead of a centralized supply chain in the supply chain obviously has the advantages of being more efficient and transparent.

As supplies become more widely distributed, the risk of conflicts, mismatches and inconsistencies in traditional supply chains increases. Blockchain can allow for better tracking and reporting, increasing transparency in supply chain processes, thereby improving delivery schedules. For example, GPS-based vehicle tracking devices can be used with blockchain to provide the blockchain with data that cannot be overwritten and tampered with, which can reduce costs and increase efficiency when it comes to logistics vehicle tracking.

Contemporary supply chains are more complex, dynamic and uncertain than ever because they involve many departments. So create a flexible supplySupply chain is the key to achieving sustainable competitive advantage. A flexible supply chain improves delivery processes and quickly moves products to required markets.

Business transactions are becoming increasingly volatile and global. Agility is achieved when a company can effectively respond and adapt to competitor disruptions and demand changes throughout the supply chain to meet customer needs.

Rapid economic and technological development requires increased flexibility in both internal (marketing and manufacturing) and external (supply and distribution) supply chains. Companies with flexible supply chains can be more resilient in uncertain situations. Respond quickly and provide the company with the ability to demonstrate products and services quickly and effectively.

In a globalized world, competition has spread to the entire supply chain, not just companies. Therefore, supply chain members need to reorganize themselves to balance the organization's ability to respond to market changes by increasing flexibility.

In today's economic environment, companies outsource some business processes to ensure supply chain flexibility, which often results in a loss of control and visibility of various logistics operations. Thanks to digital technologies, visibility into integrated transport and logistics systems will be achieved at all stages of goods delivery, from manufacturer to end user. Companies need to share information directly so it can be quickly applied to every company in the supply chain, thereby increasing supply chain agility.

So this requires different information to ensure that the chain can function as a whole. Therefore, information transferred from one organ to another should be helpful and available elsewhere in the chain.

Blockchain technology serves customers by facilitating tracking and tracing of orders from various stages of production to delivery and quick adjustments. The applications brought about by blockchain technology can only be implemented at specific touch points in the network if accepted by the relevant parties, thus controlling the data security of all supply chain transactions.

Blockchain can increase supply chain visibility and enable real-time data sharing over the network. Therefore, blockchain can support supply chain flexibility strategies by reducing the number of stakeholders affected by disruptions.

At the same time, blockchain can also quickly integrate all on-chain processes to improve forecasting and management of demand, thereby achieving more realistic supply and inventory management.

Blockchain technology has become one of the most common concepts today. As digitization becomes a common phenomenon, we have begun to digitize our assets.

Blockchain can serve as an effective tool to build trust in the supply chain by increasing transparency and flexibility in the supply chain. However, Maoqiu Technology also believes that for blockchain to be truly realized in supply chain applications, it is inseparable from mutual trust between enterprises. Only in this way can an effective consensus basis be formed, mutual collaboration capabilities improved, andSupply chain operational efficiency.

㈧ Intensive reading of blockchain papers - Pixel: Multi-signatures for Consensus

The paper mainly proposes a multi-signature algorithm Pixel for the consensus mechanism PoS.

All PoS-based blockchains as well as allowed blockchains have a common structure where nodes run a consensus sub-protocol to reach consensus on the next block to be added to the ledger. Such consensus protocols typically require nodes to check blocking proposals and express their agreement by digitally signing acceptable proposals. When a node sees enough signatures from other nodes on a specific block, it appends them to its view of the ledger.

Since consensus protocols typically involve thousands of nodes working together to reach consensus, the efficiency of the signature scheme is crucial. Furthermore, in order for outsiders to effectively verify the validity of the chain, signatures should be compact for transmission and should be verified quickly. Multisigs have been found to be particularly useful for this task because they enable many signers to create compact and efficient verifiable signatures on a public message.

Additional knowledge: Multi-signature
is a digital signature. In digital signature applications, multiple users are sometimes required to sign and certify the same file. For example, if a statement issued by a company involves the finance department, development department, sales department, after-sales service department and other departments, and needs to be signed and approved by these departments, then these departments need to sign the statement document. A digital signature scheme that enables multiple users to sign the same file is called a multi-digital signature scheme.
Multi-signature is an upgrade of digital signatures, which makes it possible to apply blockchain-related technologies to all walks of life. In actual operation, a multi-signature address can be associated with n private keys. When operations such as transfers are required, funds can be transferred as long as m private keys are signed, where m must be less than or equal to n, that is to say m/n is less than 1, it can be 2/3, 3/5, etc., which must be determined when establishing this multi-signature address.

This article proposes the Pixel signature scheme, a pairing-based forward secure multi-signature scheme that can be used in PoS-based blockchains and can significantly save bandwidth and storage requirements. To support a total of T time periods and a committee of size N, multisig contains only two group elements, and verification requires only three pairings, one exponentiation and N -1 multiplications. Pixel signatures are almost as effective as BLS multi-signatures and also satisfy forward security. Additionally, just like in BLS multi-signatures, anyone can non-interactively aggregate individual signatures into a multi-signature.

Beneficial effects:
To validate Pixel's design, compare the performance of Pixel's Rust implementation with previous tree-based forward security solutionsprograms were compared. Shows how to integrate Pixel into any PoS blockchain. Next, Pixel is evaluated on the Algorand blockchain, showing that it yields significant savings in storage, bandwidth, and block verification time. Our experimental results show that Pixel is effective as a stand-alone primitive and used in blockchains. For example, compared to a set of N = 1500 tree-based forward security signatures (for T = 232) with a 128-bit security level, a single Pixel signature that can authenticate the entire set is 2667 times smaller and can be verified 40 times faster . Pixel signing reduces the size of Algorand blocks of 1500 transactions by approximately 35% and reduces block verification time by approximately 38%.

The biggest difference compared to the traditional BLS multi-signature scheme is that BLS does not have forward security.

Compared with the tree-based forward security signature, the tree-based forward security signature can meet the security requirements, but the signature it constructs is too large and the verification speed needs to be improved. The design of this article reduces the signature size and verification time.

Supplementary knowledge: Forward security
is a security property of communication protocols in cryptography, which means that the leakage of a long-term master key will not lead to the leakage of past session keys. Forward security protects past communications from future exposure of passwords or keys. If a system has forward security, historical communications can be kept safe if the master key is compromised, even if the system is under active attack.

Build forward-secure signatures with Hierarchical Identity Based Encryption (HIBE) and add the ability to securely aggregate signatures on the same message and generate public parameters without a trusted set. To achieve:
1. Generate and update keys
2. Security against malicious key attacks
3. Invalid trust settings

For common post-attacks There are two variants:
1. Short-range variant: The adversary attempts to undermine committee members before a consensus agreement is reached. Resolution: Address short-range attacks by assuming the attack latency is longer than the running time of the consensus subprotocol.
2. Remote variant: solved by fork selection rules.
Forward secure signatures provide a clean solution to both attacks without the need for fork-choice rules or other assumptions about adversaries and clients. (Explain the advantages of forward secure signatures).

Permissioned blockchain consensus protocols (such as PBFT) are also at the core of many permissioned chains (such as Hyperledger), where only approved parties can join the network. Our signature scheme can be similarly applied to this setting to achieve forward secrecy, reduce communication bandwidth and generate compact block certificates.

Traditional Bellare-Miner model, the forward security signature scheme FS of the message space M consists of the following algorithms:
1. Setup
pp ←Setup(T), pp is a public parameter agreed by all parties, Setup(T) Represents the distribution settings for fixed parameters within the T time period.

2. Key generation
(pk,sk1) ←Kg
The signer runs the key generation algorithm on the input maximum time period T to generate public verification for the first time period Key pk and initial secret signing key sk1.

3. Key update
skt+1←Upd(skt) The signer uses the key update algorithm to update the secret key skt of time period t to skt + 1 of the next period. This scheme can also provide a "fast-forward" update algorithm skt0←$Upd0(skt,t0) for any t0 > t, which is more efficient than repeatedly applying Upd.

4. Signing
σ ←Sign(skt,M), when inputting the current signature key skt message m∈M, the signer uses this algorithm to calculate the signature σ.

5. Verification
b ← Vf(pk,t,M,σ) Anyone can verify the message M within the time period t under the public key pk by running the verification algorithm The signature of signature M. This algorithm returns 1 indicating that the signature is valid, otherwise it returns 0.

1. Relying on asymmetric bilinear groups to improve efficiency, our signature is located in G2×G1 instead of G2^2. This way, it is enough to give public parameters into G1 (which we can then use hash curve instantiation without trust setup) without having to generate "consistent" public parameters (hi, h0 i) = (gxi 1, gxi 2) ∈G1×G2.

2. Key generation algorithm, public key pk is smaller, and parameter settings improve security.

In addition to the algorithm of the forward secure signature scheme in Section 3, the forward secure multi-signature scheme FMS in the key verification model also has a key generation that additionally outputs the public key Proof of π.
Added Key aggregation, Signature aggregation, and Aggregate verification. It also proves its correctness and security on the premise of meeting the multi-signature function of forward security.

1. PoS is protected from subsequent damage
Subsequent damage: Post-verified nodes attack and destroy the previous consensus verification state.
Many users at the same timeWhere many signatures are propagated on a single message (such as a block of transactions), Pixel can be applied to all of these blockchains to protect against follow-on attacks and potentially reduce bandwidth, storage and computational costs.

2. Pixel integration
In order to vote on block B, each member of the sub-protocol signs B using a Pixel with the current block number. Consensus is reached when we see the set of N committee members signing on the same block B, where N is some fixed threshold. Finally, we aggregate these N signatures into a single multi-signature Σ, and the pair (B, Σ) forms a so-called block certificate and append block B to the blockchain.

3. Register a public key
Every user who wants to participate in the consensus needs to register a participating signing key. Users first sample Pixel key pairs and generate corresponding PoPs. The user then issues a special transaction (signed under her consumption key), registering a new participation key. Transactions include PoP. Select the PoS validator that reached agreement in round r to check (a) the validity of the special transaction and (b) the validity of the PoP. If both checks pass, the user's account is updated with the new participation key. From this point, if checked, the user will use the Pixel login block.
That is, constantly changing its own participation key to achieve forward security.

4. Propagation and aggregation of signatures
The signatures of each committee will be propagated through the network until the signatures of N committee members are seen on the same block B. Note that Pixel supports non-interactive and incremental aggregation: the former means that signatures can be aggregated by any party after broadcast without contacting the original signer, while the latter means that we can add new signatures to a multisig to obtain new of multi-signatures. In practice, this means that the propagating node can perform intermediate aggregation on any number of committee signatures and propagate the results until a block certificate is formed. Alternatively, nodes can aggregate all signatures before writing the block to disk. That is, after receiving enough block certification votes, a node can aggregate the signatures of N committee members into a multi-signature and then write the block and certificate to disk.

5. Key update
When using Pixel in the blockchain, time corresponds to the block number or sub-step in the consensus protocol. When relating time to block numbers, it means that all eligible committee members should update their pixel keys every time a new block is formed and the reincarnation number is updated.

Conduct an experimental evaluation on the Algorand project, and compare it with the Algorand project's own solution to prevent post-corruption attacks, BM-Ed25519, and the BLS multi-signature solution.

On storage space:

Save bandwidth:
Algorand uses a relay-based propagation model, where the user's nodes are connected to a network of relays (nodes with more resources). Without aggregation during propagation, the bandwidth pixel savings for relays and regular nodes come from smaller signature sizes. Each relay can serve dozens or hundreds of nodes, depending on the resources it provides.

Save verification time