区块链技术防篡改,区块链技术如何保证防伪,防篡改特性?

1. Which technology ensures the decentralization of the blockchain?

The decentralization of the blockchain is ensured by the P2P communication protocol technology of.

Blockchain technology has never excluded supervision, and the supervision nodes can be easily connected to any blockchain network. Due to the public and transparent nature of the blockchain, regulatory agencies can more easily monitor the transaction data of the entire system, and due to the tamper-proof nature of the blockchain.

Once a transaction occurs, it cannot be changed or deleted. It is impossible for data fraud to deceive supervision, and it is more conducive for regulatory agencies to supervise market behavior. It can be seen that blockchain will become an important tool for regulatory technology (RegTech).

2. Blockchain: Tamper-proof Hash Encryption Algorithm

Students A and B toss a coin in the classroom and bet on who will clean the house. If heads come up, A will clean. If the tail is up, then B sweeps. There is nothing wrong with this strategy.

However, if the scenario is transferred to an online chat room, and A and B also play a coin-tossing game, B will probably not agree, because when A tosses a coin, B will not guess.

Heads or tails, A can say that B guessed wrong.

How to solve this problem? How about encrypting the result of the coin toss first, and then B guesses? You can try this method.

Assume that any odd number represents the front side of the coin, and any even number represents the tail side. A wants a number 375, then multiplies it by 258, tells B the result is 96750, and declares that the 375 A wants is the key, which he keeps for safekeeping.
When verifying the result next, A can lie and claim that 258 is the number he wants and 375 is the key, and A is still invincible. What if A tells B the key in advance? B can directly calculate the original number, losing the confidentiality function.

This method of knowing the encryption method and knowing the decryption method obviously does not work. Is there a way to know the encryption method and still not be able to recover the original text?

Obviously there is, it is OK to add irreversible operations to the encryption process. A designs a new encryption method:

Assume that the number A wants is 375 and encrypts it:

B gets the result 120943, but he can hardly calculate the key 375 based on 120943.
If B wants to verify whether A is lying:

Finally, he can flip a coin...

This encryption method that loses part of the information is called "one-way encryption". Also called hash algorithm.

There is a problem:

This is possible, but it can be solved by increasing the difficulty of the above algorithm so that A is difficult to find.

According to the above statement, a reliableThe hash algorithm should satisfy:

The hash function in cryptography has three important properties, namely collision resistance, preimage irreversibility, and problem friendliness.

Collision means that student A can find out an odd and an even number in advance to make the hash results consistent, which is computationally infeasible.

First of all, if the news about the large space sauna is compressed into a small space, there will definitely be a collision. Assume that the length of the hash value is fixed to 256 bits. If the order is 1, 2,...2 256 + 1, these 2 256 + 1 input values, and the hash values ​​are calculated one by one, you will definitely be able to find two input values ​​that make the hash The values ​​are the same.

Student A, when you see this, please don’t be too happy too early. Because you have to have time to figure it out before it's yours. Why do you say that?

According to the birthday paradox, if 2 130 +1 inputs are randomly selected, there is a 99.8% probability of finding at least one pair of collision inputs. Then for a hash function with a hash value length of 256 bits, an average of 2128 hash calculations need to be completed to find the collision pair. If a computer performed 10,000 hash calculations per second, it would take approximately 10 27 years to complete 2 128 hash calculations.

Student A, don’t think about cheating, I guess you won’t live this long. Of course, it is possible if computer computing power is greatly improved.

So what other uses does integrity have?

Used to verify the integrity of the information, because if the information is not tampered with during transmission, the hash value obtained by running the hash calculation will be different from the original hash value.

Therefore, in the blockchain, the collision resistance of the hash function can be used to verify the integrity of blocks and transactions.

Because a hash value corresponds to countless plaintexts, theoretically you don't know which one it is. For example, the results of 4+5=9 and 2+7=9 are the same. I know that the result I entered is 9, but can I know what number I entered?

If, when performing hash calculation on message m, a random prefix r is introduced, and based on the hash value H(r||m), it is difficult to recover message m, which means that the hash function The value hides message m.

Therefore, student B, it is impossible to deduce the original data based on the results. It is like finding a needle in a haystack.

Problem friendliness means that there is no convenient way to generate a hash value that meets special requirements. What does it mean? In layman's terms, there is no shortcut, you need to figure it out step by step. If the required hash result starts with several 0s, then the number of hash calculations required to find a hash value with the first 3 digits all being 0 and a hash value with the first 6 digits all being 0 is a certain number. Quantitative relationship.

How can this be used? In the blockchain, it can be used as proof of work in the consensus algorithm.

Mainly describes three important properties of hash functions: collision resistance, preimage irreversibility, and problem friendliness.

Because of these important properties, functions such as integrity verification of blocks and transactions in the blockchain and workload proof of the consensus algorithm are implemented using hash functions.

[1]. Zou Jun, Zhang Haining. Blockchain Technology Guide [M]. Beijing: Mechanical Press, 2016.11
[2]. Chang Chai, Han Feng. Blockchain From digital currency to credit society [M]. Beijing: CITIC Press, 2016.7
[3]. Zhang Jian. Blockchain defines the new future financial and economic landscape [M]. Beijing: Machinery Industry Press, 2016.6

3. How is the evidence stored in Yibaoquan’s blockchain tamper-proof

1. Yibaoquan’s blockchain technology

Yibaoquan’s blocks The chain is built based on the BCOS open source platform. It uses the SHA-512 hash algorithm, timestamp service, and PBFT consensus algorithm to calculate metadata and can flexibly expand the alliance chain institutions and nodes. The data stored and preserved on the blockchain through Yibaoquan will be stored on the blockchain in the form of hash values. Through the characteristics of blockchain decentralization and distributed storage, the authenticity and objectivity of the data can be effectively guaranteed. Effectively tamper-proof.

2. Yibaoquan blockchain certificate storage

Yibaoquan uses blockchain technology to cooperate with notary offices, judicial appraisal centers, arbitration committees, Internet courts, copyright protection centers, and CAs An open platform for the security chain initiated by institutions and others and open to the outside world. Allow electronic data to be synchronized from generation, storage, to final use to each node of the preservation chain open platform, for synchronous supervision and notarization, and the issuance of relevant certificates and blockchain queries, effectively ensuring the integrity of the data. Judicial effectiveness.

4. Why the blockchain can be tamper-proof

The blockchain is linked together in an orderly manner from scratch. Each area Blocks all point to the previous block, which is called the child block of the previous block, and the previous block is called the parent block.

Each block has a block header, which contains the hash value generated by the algorithm of the parent block header. The parent block can be found through this hash value. When there are any changes to the parent block, the hash value of the parent block also changes. This will force the sub-block hash value field to change, and so on, subsequent sub-sub-blocks, sub-sub-sub blocks will be affected. Once a block has many descendants, it is necessary to recalculate the blocks of all descendants of this block. However, such recalculation requires a huge amount of calculation, so the longer the blockchain, the harder it is to change the block history.

5. How to correctly understand the non-tampering characteristics of blockchain technology

The analysis of Chongqing Jinwowo Network is as follows:
Based on the characteristics of decentralization, even if The blockchain has suffered serious hacker attacks, as long as the number of nodes controlled by hackers is notWith more than half of the total number of global nodes, the system can still operate normally and the data will not be tampered with.
This is a distributed data storage based on blockchain. Because there is no centralized management center, even if a node is attacked or tampered with in the blockchain system, it will not affect the health of the entire network. operation.
Because the rights and obligations of all nodes are equal, and activities will be supervised by the entire network. At the same time, each of these nodes has the ability to vote using computing power, which ensures that the recognized result is the result recognized by more than half of the nodes.

6. A brief analysis of the application of blockchain technology

Today we will talk about the application analysis of blockchain technology in the field of public resource transactions
Public resource transactions, both It includes the purchase of public resources by the public sector, such as government procurement, construction project bidding, etc.; it also includes the sale of public resources by the public sector, such as the bidding, auction and listing of state-owned land, the transfer of mining rights, the sale of state-owned forest rights, and state-owned financial assets. Disposal and other public resource sales involving public interests and public safety. Public resource transactions are related to the national economy and people's livelihood, and involve the fundamental interests of the people. Therefore, public resource transaction management has always been an important management function of my country's government affairs management.
In recent years, the National Information Center has continued to promote the construction of a public resource trading service platform, giving full play to the role of a public entrance to trading services, a public channel for data sharing, and comprehensive technical support for cross-regional transactions. The integration of public resource trading platforms based on digital technology has achieved remarkable results. Among them, blockchain technology has the characteristics of consistent data storage, difficulty in tampering, and traceability. It provides new ideas and solutions to solve the problem of trust in public resource trading data. path.

Information data management issues in the field of public resource transactions

Objectively speaking, various credit deficiencies have long existed in the field of public resource transactions in my country, which not only disrupts the normal market transaction order, but also It affects the fairness and justice of market competition, and also poses serious risks and threats to the quality of project construction and construction safety production. The reason is that the root cause of credit risk lies in the information asymmetry between entities in the public resource trading market, and in the limitations and defects of traditional public resource trading management on information data security and information data use.

Data security management issues

Various transaction information and credit information in the field of public resource transactions contain huge value. Under the increasingly electronic development trend of domestic public resource transaction management and services, including electronic bidding user identity information, potential bidder information, bid evaluation committee composition information, bid document information, judges' bid evaluation information, and bid evaluation result information Various types of information security risks have increasingly become important issues affecting the efficiency, quality, and fairness of public resource transactions.
Traditional data security technology is difficult to effectively avoid security management problems such as leakage, tampering, and loss of various information data, especially under some technical means, related data operationsIt is difficult to trace traces of operations, causing great trouble for data security management.
Data sharing application issues
The main reason for the long-standing problems of various credit deficiencies and untrustworthy behaviors in the public resource trading market is that there are limitations in the sharing and application of relevant credit information of market entities.
On the one hand, a large amount of credit information of market entities has been deposited in various departments for a long time and has not been fully exploited;
On the other hand, the credit information of public resource trading market entities involves banks, public security, courts, housing Among many management departments such as construction, human resources and social security, and taxation, the long-standing phenomenon of “data islands” and “data fog islands” among different management departments hinders the efficient sharing and application of credit information in the public resource trading market.
Blockchain and public resource transaction information data management
According to the "China Blockchain Technology and Application Development White Paper 2016" issued under the guidance of the Ministry of Industry and Information Technology, in a broad sense, blockchain technology is the use of blocks Chained data structures are used to verify and store data, distributed node consensus algorithms are used to generate and update data, cryptography is used to ensure the security of data transmission and access, and smart contracts composed of automated script codes are used to program and operate data. A new distributed infrastructure and computing paradigm.
Essentially, blockchain technology is a technical solution that collectively maintains a reliable database in a decentralized, high-trust manner. In layman's terms, blockchain technology can be seen as an accounting method that supports the participation of all people.
Traditional data accounting involves multiple accounting entities and generates multiple data ledgers. Under this accounting method, due to the risks of lack of supervision, technical security risks, and physical security risks, the account data may be tampered with or lost, and it is difficult to trace relevant operational behaviors. Therefore, the objectivity, fairness, and security of the account data must be It’s hard to guarantee.
Blockchain technology provides a technical solution that supports multiple accounting entities to participate in accounting. When any accounting subject modifies the ledger, its modification behavior will form indelible traces (timestamps) in the ledger records, and the modification results will be synchronized to the ledgers of all accounting subjects, which prevents the account from being The risk of data tampering and loss can be traced back to relevant accounting behaviors to promote supervision.

In response to the information data management and credit issues raised above in the field of public resource transactions, blockchain technology can use its own "decentralization", "distributed data storage" and "traceability" ”, “anti-tampering characteristics”, “openness and transparency” and other advantageous features to effectively respond and solve.
Public resource transaction data is tamper-proof
The public resource transaction platform stores a large amount of public resource transaction data. With traditional centralized data storage management, once the data and backup are damaged or lost, it is difficult to recover, and due to There are loopholes in the supervision mechanism and the risk of data tampering.
Blockchain technology adopts "decentralization" and "distribution""Data storage", data damage or loss in one or more data storage nodes will not affect the data security of other data storage nodes. At the same time, the updates of the data ledger records are synchronously shared and made public, and operation traces are supported. Unless all nodes All are destroyed, otherwise the blockchain data will not be tampered with or damaged.
Establish a trustworthy public resource transaction data environment
Asymmetric information in the public resource transaction market leads to adverse selection and moral hazard among market entities , affecting the efficiency and quality of public resource transactions, and affecting the orderly operation and development of the public resource transaction market.
Blockchain technology solves the issues of authenticity, security and openness of public resource transaction data, and promotes the credibility of the public resource transaction market The efficient sharing and application of information promotes the establishment of a trustworthy data environment for public resource transactions, prevents and avoids various credit risks, and provides trustworthy data decision-making support for market transaction entities and regulatory entities

7. Blockchain How is the security and what are the risks of blockchain?

The hottest topic at the beginning of the new year is blockchain, but there are still many people who have doubts about its security and risks. Attitude, how about the security of blockchain? What are the risks of blockchain? Below we will answer them one by one for everyone. I hope it will be helpful to you after reading it.
Security of Blockchain Anyuan How about it?
First of all, blockchain is a distributed database technology. Distributed technology mainly refers to storage architecture. The distributed architecture adopted by blockchain not only stores ledger data on each node, but also Fiber and each node must contain the data of the entire ledger. This completely distributed architecture brings extremely high security, and no one can destroy all nodes at the same time.
Secondly, blockchain technology Tamper resistance can be achieved through "blocks" and "chains". The unit for storing data in a blockchain is a block. When each block is generated, it must contain the unique "characteristic value" of the previous block (which can be viewed as Block ID card), each block is lined up strictly in the order of generation time, forming a "chain".
Security is a major feature of blockchain technology. But from the perspective of privacy protection, blocks The Crack Fake Blockchain emphasizes openness and transparency, and any node has the right to operate according to the consensus algorithm, so it is not suitable for scenarios where data privacy needs to be protected.
What are the risks of blockchain?
1. Technical risk: For example, the launch of Ethereum was once popular, but because it is a digital currency with smart contracts, it brings the risk of hacker attacks due to possible loopholes in smart contracts. The largest crowdfunding project of Ethereum, THEDAO, was hacked and lost money. More than 60 million US dollars.
2. Legal risks: legality issues of digital currency issuance, notarization and confirmation of rights, and legality issues of evidence, including legality issues of smart contracts, digital bills, accounting and liquidation, and equity crowdfunding , currently it is still blank in law in our country and other countries around the world.
3. Criminal risk: using digital currency to issue money and then absconding with the money, using digital currency to launder money and violate laws.Legal gambling, using its designed smart contracts and digital bills to defraud profits, using blockchain technology to commit anonymous crimes, etc. Due to the current regulatory gap, there may be huge criminal risks.
The above is what the editor brings to you. How about the security of blockchain? What are the risks of blockchain? of the entire content.

8. What convenience can the blockchain service platform launched by JD.com bring to the operation of enterprises?

The concept of blockchain has become very popular in recent years, but in addition to digital currency ( Except for use in the field of virtual currency), there have not been many implementation projects in other fields. JD.com’s recently released “Zhi Zhen Chain” can be said to be an important attempt to implement blockchain in business scenarios. After all, JD.com itself is already very large and has established a relatively complete ecosystem. If “Zhi Zhen Chain” If it can gradually be implemented and play a role within the JD system, it will have a lot of reference value for blockchain applications in the commercial field.

The blockchain itself has the characteristics of tamper-proof, traceability, full process, decentralization, etc., and these characteristics are more consistent with the e-commerce field where market operation is relatively clear. In my opinion, the blockchain platform created by JD.com can bring the following benefits:

First, products can be traced. Product anti-counterfeiting has always been a headache for e-commerce platforms, and it also accounts for a large part of the e-commerce platform's expenses. After using blockchain technology, product tracking can be completed to ensure product traceability. Product authenticity will no longer be a problem that troubles merchants.

Second, the service is traceable. Not only products can be traced, but services can also be traced using blockchain technology. Services that follow products are often one of the core factors that affect user experience. Making services traceable can build a service system to facilitate smoother connection and cooperation between merchants and between merchants and users.

Third, standardize bill (contract) management. Invoice management has always been a troublesome matter in a business environment. After using blockchain, standardized management of invoices can be completed. Blockchain notes have natural characteristics such as being unforgeable, tamperable, traceable, and verifiable, and these characteristics can avoid a large number of transaction risks.

Fourth, the process is intelligent and standardized. By using the "Smart Chain", many companies participating in the JD platform can effectively use the "Smart Chain" to complete various business operations (to be developed and improved), which greatly lowers the entry threshold for participating companies.

I believe that the "Smart Chain" will be further developed and improved in the future, and will also bring more convenience and benefits to service merchants.

My research direction is big data and artificial intelligence. I am currently leading graduate students in related fields. I will continue to write some popular science articles on big data on Toutiao. Friends who are interested can check it out. If you pay attention to me, I believe you will gain something from the demolition tribe.

If you have any questions about big data, you can also consult me.

Thank you!

9. Using blockchain technology can avoid tampering with clinical trial data

Blockchain technology can ensure the integrity of clinical trial data through immutable trial recording protocols.

??

Bitcoin was created to free people from centralized money systems and flawed policies set by central governments and central banks Saved. When Satoshi Nakamoto published his white paper on Bitcoin, no one could have imagined that it would indeed save people down the long road.

As developers continue to mine new applications for the blockchain technology underlying Bitcoin, one of the major breakthroughs is in the area of ​​drug development and testing processes. Drug development is an expensive and time-consuming process. Even though the drug modeling process greatly reduces the time to develop a new drug, it still takes years, even decades, to launch a new drug into the market. In order for the drug to be released, it must first pass rigorous trials in lab mice and humans. Only if it passes safety review by relevant regulatory agencies, such as the U.S. Food and Drug Administration, can it be marketed.

Even if a drug is very effective in treating a certain disease, it may still have serious side effects that may even be fatal. Monitoring a clinical trial involves not only checking its effectiveness but also verifying its side effects and weighing the pros and cons of both.

However, pharmaceutical companies and scientists may selectively share only the positive effects of a drug and ignore the negative effects. Take the antidepressant drug paroxetine, which reported that Effective for depressed patients. However, later studies proved that the drug was not as effective as they claimed. On the contrary, it caused suicidal side effects in patients.

Recording clinical trial protocols on the blockchain

To prevent pharmaceutical companies and researchers from tampering with data, Greg Irving, a PhD and researcher at the University of Cambridge, created a blockchain system to Records and individually verifies specified clinical trial protocols. The immutability of the Bitcoin blockchain was used by Greg Irving, and his research has been published in F1000 Research (which can be regarded as an academic journal).

The purpose of this project created by Greg Irving is to ensure that pharmaceutical companies and researchers do not modify the actual trial protocols to match the results. As part of the proof of concept, Greg Irving used a research protocol from the ClinicalTrials.gov website. He creates a plain text folder containing the specified endpoints and planned analysis. The data in the plain text folder is then converted into data calculated by a SHA-256 hash calculator. The resulting SHA-256 hash value will serve as a private key for the Strongcoin Bitcoin wallet, and the public key generated from the private key will ensure the transaction. Transactions will be recorded on the blockchainpublic key, making it easily verifiable on the blockchain.

Now, any plain text containing a clinical trial protocol can follow the same steps to generate a public key. This initially generated and verified public key will be able to conduct any transaction on the blockchain. . If the public keys in both cases match, then it not only proves the existence of the timestamped document, but also verifies that the document has not been altered in any way. If any changes are made, the SHA-256 hash created will be different from the original, resulting in a different public key.

Greg Irving described the entire process as being cost-effective because Bitcoin can retrieve the existence of confirmation files from the wallet while maintaining the integrity of the clinical trial protocol. Greg Irving took a manual approach to creating this proof of concept, but the same thing could be done automatically and made public. Any changes will cause the protocol to be recorded as a separate entry, and the corresponding public and private keys can be verified.

The work of Greg Irving and John Holden is to be consistent with Helsinki's declaration, which requires that all clinical trials be recorded and published in a public database to prevent arbitrary tampering with data and undermine published research. of integrity.

10. How micro-copyright webpage evidence collection and blockchain encrypted storage can help make the judiciary more credible

As of December 2022, "online infringement" cases will be searchable on China's Judgment Documents Online The number has reached 13,644. With the increasing number of online infringement cases, compliant and effective online evidence collection methods have become an urgent need. Among network forensic methods, web page forensics has always been the focus. The use of web page evidence has surged since 2012 and is becoming more and more widely used.
Enter the web forensics page from the micro copyright official website to create a new forensic. Just enter the URL address, and the system will automatically crawl the web forensics, and at the same time obtain information such as the IP registration of the infringing website, realizing the preservation of the entire evidence chain and preventing repudiation. The system also supports batch evidence collection and can capture multiple infringing web page information at one time, saving time, effort and links.
Microcopyright uses blockchain technology through the open platform of the preservation chain to encrypt and store forensic evidence on the blockchain and simultaneously store the evidence in notary offices, judicial appraisal centers, copyright protection centers, Internet courts and other nodes. Timely solidify infringing content to effectively prevent tampering.
After the webpage evidence is stored, it can be stored in the notary office, arbitration committee, Yibaoquan Electronic Data Preservation Center and other nodes on the preservation chain platform through the registration number query in the blockchain verification of the micro-copyright webpage evidence collection page. Untampered forensic evidence. When necessary, an electronic data evidence collection certificate can be issued in court. By scanning the QR code on the certificate, the entire infringement process can be reproduced to the judge and evidence can be given in court to safeguard rights!