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⑴ Characteristics of blockchain technology

The five basic characteristics of blockchain technology are as follows:
1. Characteristics of blockchain technology 1: distributed database< br>Every party on the blockchain has access to the entire database and its complete history. No single party controls the data or information. Each party can directly verify the records of its trading partners without the need for a middleman.
2. Blockchain technology feature 2: Peer-to-peer transmission
Communication occurs directly between peers, rather than through a central node. Each node stores and forwards information to all other nodes.
3. Blockchain technology feature three: Transparent anonymity
Any user with access to the system can see each transaction and its associated value. Each node or user on the blockchain has a unique address consisting of more than 30 letters and numbers, which is used to identify itself. Users can choose to remain anonymous or provide proof of their identity to others. The addition of the blockchain occurs at one of these addresses.
4. Blockchain technology feature four: Irreversibility of records
Once a transaction is entered in the database and an account is updated, the records cannot be changed because they are linked to every transaction record before them (hence the name "chain"). Various algorithms are employed to ensure that records in the database are permanent, chronologically ordered, and accessible to all other nodes on the network.
5. Features of Blockchain Technology Five: Computational Logic
The digital nature of the ledger means that blockchain transactions can be associated with computational logic and are essentially programmable. Therefore, users can set algorithms and rules that automatically trigger transactions between nodes.
Extended information:
Blockchain is a chain composed of blocks one after another. Each block stores a certain amount of information, and they are connected into a chain in the order in which they were generated. This chain is saved in all servers. As long as one server in the entire system can work, the entire blockchain is safe. These servers are called nodes in the blockchain system, and they provide storage space and computing power support for the entire blockchain system. If you want to modify the information in the blockchain, you must obtain the consent of more than half of the nodes and modify the information in all nodes. These nodes are usually in the hands of different subjects, so it is extremely difficult to tamper with the information in the blockchain. thing. Compared with traditional networks, blockchain has two core characteristics: data is difficult to tamper with and decentralized. Based on these two characteristics, the information recorded in the blockchain is more authentic and reliable, and can help solve the problem of people's mutual distrust.

⑵ What is blockchain technology? What exactly is blockchain? A chain data structure composed of sequential connections, and a cryptographically guaranteed distributed ledger that cannot be tampered with or forged.

Broadly speaking, blockchain technology uses block chain data structures to verify and storeData, a new distributed infrastructure that uses distributed node consensus algorithms to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses smart contracts composed of automated script codes to program and operate data. and calculation methods.

[Infrastructure]

Generally speaking, the blockchain system consists of data layer, network layer, consensus layer, incentive layer, contract layer and application layer composition. Among them, the data layer encapsulates the underlying data blocks and related basic data and basic algorithms such as data encryption and timestamps; the network layer includes distributed networking mechanisms, data dissemination mechanisms, and data verification mechanisms; the consensus layer mainly encapsulates network nodes Various consensus algorithms; the incentive layer integrates economic factors into the blockchain technology system, mainly including the issuance mechanism and distribution mechanism of economic incentives; the contract layer mainly encapsulates various scripts, algorithms and smart contracts, and is the core of the blockchain The basis of programmable features; the application layer encapsulates various application scenarios and cases of the blockchain. In this model, the chain block structure based on timestamps, the consensus mechanism of distributed nodes, economic incentives based on consensus computing power, and flexible programmable smart contracts are the most representative innovations of blockchain technology.

Extended information:

[Blockchain core technology]

Blockchain mainly solves the trust and security issues of transactions, so it addresses this issue Four technological innovations:

1. Distributed ledger means that transaction accounting is completed by multiple nodes distributed in different places, and each node records a complete account, so they all Can participate in supervising the legality of transactions and can also jointly testify for them.

The uniqueness of blockchain's distributed storage is mainly reflected in two aspects: First, each node of the blockchain stores complete data according to the block chain structure. Traditional distributed storage generally stores The data is divided into multiple parts for storage according to certain rules. Second, the storage of each node in the blockchain is independent and of equal status, relying on the consensus mechanism to ensure storage consistency, while traditional distributed storage generally synchronizes data to other backup nodes through the central node.

No node can record ledger data independently, thus avoiding the possibility of a single bookkeeper being controlled or bribed to record false accounts. Also because there are enough accounting nodes, theoretically speaking, the accounts will not be lost unless all nodes are destroyed, thereby ensuring the security of the accounting data.

2. Asymmetric encryption and authorization technology. Transaction information stored on the blockchain is public, but account identity information is highly encrypted and can only be accessed with authorization from the data owner. , thus ensuring data security and personal privacy.

3. The consensus mechanism is how all accounting nodes reach a consensus to determine the validity of a record. This is both a means of identification and a means of preventing tampering. Blockchain proposes four different consensus mechanisms, suitable for different application scenarios, in terms of efficiency and security.strike a balance between sex.

The consensus mechanism of the blockchain has the characteristics of "the minority obeys the majority" and "everyone is equal". "The minority obeys the majority" does not entirely refer to the number of nodes, but can also be the computing power and the number of shares. Or other characteristic quantities that the computer can compare. "Everyone is equal" means that when a node meets the conditions, all nodes have the right to give priority to the consensus result, which will be directly recognized by other nodes and may eventually become the final consensus result.

4. Smart contracts. Smart contracts are based on these trustworthy and non-tamperable data and can automatically execute some predefined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and trustworthy, it will be easy to automate claims settlement in some standardized insurance products.

In the daily business of insurance companies, although transactions are not as frequent as those in the banking and securities industries, the reliance on trusted data continues unabated. Therefore, the author believes that using blockchain technology from the perspective of data management can effectively help insurance companies improve their risk management capabilities. Specifically speaking, it is mainly divided into risk management of policyholders and risk supervision of insurance companies.

Blockchain-Network

⑶ How to verify the integrity of blockchain evidence data through micro-copyright

"About handling criminal cases" Article 5 of the Provisions on Case Collection, Extraction, Review and Judgment of Several Issues in Electronic Data stipulates that the integrity of electronic data can be protected by calculating electronic data integrity check values, etc.

To verify the integrity of electronic data, verification algorithms such as hash values ​​are generally used.

Microcopyright uses the SHA-512 hash algorithm, timestamp service, and PBFT consensus algorithm to encrypt the original data and generate the certificate subject, certificate time, certificate process, and content. The unique corresponding digital fingerprint is encrypted and stored on the blockchain, effectively ensuring the integrity of the certificate data.

Users enter the registration number of the certificate data and upload the original file through the "Verification Preservation" on the official website of Micro Copyright. The system automatically checks the hash value of the uploaded file and the hash value of the original certificate data. Comparing, if the stored certificate data and the uploaded file are complete and correct, the verification is passed, otherwise, the verification is not passed.

⑷ What are the core blockchain technologies of blockchain technology?

What is the hottest Internet topic at the moment? It doesn’t take the editor to tell you that it is blockchain technology. However, many friends have only heard of this technology and do not have much in-depth understanding of it. So what are the blockchain technologies? Below we will bring you an introduction to the core technology of blockchain for your reference.
What are the core elements of blockchain technology?
Blockchain technology can be a public ledger (visible by anyone) or a permissioned network (visible only by those authorized), which solves supply chain challenges ,becauseIt is an immutable record that is shared among network participants and updated in real time.
Blockchain technology----data layer: designing the data structure of the ledger
Core technology 1. Block + chain:
Technically speaking, block is a data structure that records transactions. Reflects the flow of funds for a transaction. The blocks of transactions that have been reached in the system are connected together to form a main chain, and all nodes participating in the calculation record the main chain or part of the main chain.
Each block consists of a block header and a block body. The block body is only responsible for recording all transaction information in the previous period, mainly including the number of transactions and transaction details; the block header encapsulates the current version number, previous A block address, timestamp (recording the time when the block was generated, accurate to seconds), random number (recording the value of decrypting the answer to the math question related to the block), target hash value of the current block, and Merkle number Root value and other information. From a structural point of view, most functions of the blockchain are implemented by the block header.
Core technology 2. Hash function:
The hash function can convert data of any length into a set of fixed-length codes through the Hash algorithm. The principle is based on a cryptographic one-way hash function. This kind of function is easy to verify, but difficult to crack. Usually, the industry uses y=hash(x) to represent it. This hash function implements operations on x to calculate a hash value y.
Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384 and SHA-512, etc. Taking the SHA256 algorithm as an example, inputting any string of data into SHA256 will result in a 256-bit Hash value (hash value). Its characteristics: the same data input will get the same result. As long as the input data changes slightly (for example, a 1 becomes a 0), a completely different result will be obtained, and the result cannot be predicted in advance. Forward calculation (calculating the corresponding Hash value from the data) is very easy. Reverse calculation (cracking) is extremely difficult and is considered impossible under current technological conditions.
Core technology 3. Merkle tree:
Merkle tree is a hash binary tree, which can be used to quickly verify the integrity of large-scale data. In the blockchain network, the Merkle tree is used to summarize all transaction information in a block, and ultimately generates a unified hash value of all transaction information in the block. Any change in transaction information in the block will cause Merkle tree changes.
Core technology 4. Asymmetric encryption algorithm:
Asymmetric encryption algorithm is a key secret method that requires two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt the data, only the corresponding private key can be used to decrypt it, thereby obtaining the corresponding data value; if the private key is used to sign the data, then only the corresponding public key can be used to sign the data. In order to verify the signature, the sender of the verification information is the holder of the private key.
Because encryption and decryption use two different keys, this algorithm is called non-Symmetric encryption algorithm, and symmetric encryption uses the same key in the encryption and decryption process.
Blockchain technology----network layer: realize the decentralization of accounting nodes
Core technology 5. P2P network:
P2P network (peer-to-peer network), also known as point-to-point technology, is no Central server, Internet system that relies on user groups to exchange information. Unlike a centralized network system with a central server, each client in a peer-to-peer network acts as both a node and a server. Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of decentralization and robustness.
Blockchain technology----Consensus layer: allocate the task load of accounting nodes
Core technology 6. Consensus mechanism:
Consensus mechanism is how to reach consensus among all accounting nodes to identify The validity of a record is both a means of identification and a means of preventing tampering. There are currently four main types of consensus mechanisms: PoW, PoS, DPoS and distributed consensus algorithms.
PoW (Proof of Work, proof of work): PoW mechanism, which is like Bitcoin’s mining mechanism, miners package existing transactions that have not been recorded by the network into a block, and then continue to traverse and try to find a random number , so that the hash value of the new block plus the random number meets certain difficulty conditions. Finding a random number that meets the conditions is equivalent to determining the latest block of the blockchain, and is also equivalent to obtaining the current round of accounting rights of the blockchain. Miners broadcast blocks that meet the mining difficulty conditions in the Yuanfu network. After verifying that the block meets the mining difficulty conditions and that the transaction data in the block meets the protocol specifications, other nodes in the entire network will each Blocks are linked to their own version of the blockchain, thereby forming a network-wide consensus on the current network state.
PoS (ProofofStake, Proof of Stake): PoS mechanism requires nodes to provide proof of a certain number of tokens to obtain a distributed consensus mechanism for competing for blockchain accounting rights. If you rely solely on the token balance to determine the bookkeeper, you will inevitably make the rich win, which will lead to the centralization of bookkeeping rights and reduce the fairness of the consensus. Therefore, different PoS mechanisms use different methods to increase the amount of money based on the proof of equity. The randomness of accounting rights avoids centralization. For example, in the PeerCoin PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is very easyIt is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, The block generation authority is given to the witness corresponding to the next time slice. Shareholders can replace these witnesses at any time by voting. This design of DPoS makes the generation of blocks faster and more energy-saving.
Distributed Consistency Algorithm: Distributed Consistency Algorithm is based on traditional distributed consistency technology. Among them are Byzantine fault-tolerant algorithms that solve the Byzantine Generals problem, such as PBFT (Byzantine fault-tolerant algorithm). In addition, distributed consensus algorithms (Pasox, Raft) that solve non-Byzantine problems are not explained in this article. This type of algorithm is currently a commonly used consensus mechanism in alliance chain and private chain scenarios.
Taken together, POW is suitable for public chains. If you build a private chain, it is more suitable to use POS because there is no trust problem in verification nodes; and because there are untrustworthy local nodes in the alliance chain, it is more suitable to use DPOS.
Blockchain technology----Incentive layer: Develop a "salary system" for accounting nodes
Core technology 7. Issuance mechanism and incentive mechanism:
Take Bitcoin as an example. Bitcoins are initially rewarded by the system to miners who create new blocks, and this reward is halved approximately every four years. At the beginning, miners were rewarded with 50 Bitcoins for each new block recorded, and this reward is halved approximately every four years. By analogy, by around AD 2140, newly created blocks will no longer receive rewards from the system. By then, the total number of Bitcoins will be approximately 21 million. This is the total number of Bitcoins, so it will not increase indefinitely.
Another source of incentives is transaction fees. When there are no system rewards for newly created blocks, the miners' income will change from system rewards to transaction fees. For example, when you transfer, you can specify 1% of it as a handling fee to be paid to the miner who records the block. If the output value of a transaction is less than the input value, the difference is the transaction fee, which will be added to the incentive for that block. As long as a given amount of electronic currency has entered circulation, the incentive mechanism can gradually be converted to rely entirely on transaction fees, so there is no need to issue new currency.
Blockchain technology----Contract layer: giving the ledger programmable features
Core technology 8. Smart contract:
Smart contract is a set of programmed rules and logic that respond to scenarios. Implemented by decentralized, trusted shared script code deployed on the blockchain. Normally, after the smart contract is signed by all parties, it is attached to the blockchain data in the form of program code, and is recorded in a specific block of the blockchain after being propagated through the P2P network and verified by nodes. Smart contracts encapsulate a number of predefined states and transition rules, scenarios that trigger contract execution, response actions under specific scenarios, etc. The blockchain can monitor the status of smart contracts in real time and activate and execute them by checking external data sources and confirming that specific trigger conditions are met.Execute the contract.
The above is what blockchain technologies the editor has brought to you? All content of the introduction to the core technology of blockchain.

⑸ How is the anti-counterfeiting traceability application of blockchain implemented?

The three major characteristics of blockchain are well-known, which are decentralization, openness and transparency, and non-tampering. The non-tamperable feature enables blockchain to be used in many places. Such as product traceability, anti-counterfeiting, privacy protection, etc.

Because the production process it traces is all uploaded manually, so even if the data cannot be tampered with, the authenticity of the data cannot be guaranteed, and it still cannot be Solve substantive issues.

In general, although blockchain has brought great benefits, it is not perfect after all. However, blockchain technology has advanced the development of the times, and I believe its future is worth looking forward to.

⑹ The digital currency community must use blockchain technology to self-supervise

The digital currency community must use blockchain technology to self-supervise
What happens on the blockchain Self-policing of illegal actions may soon become a necessity for the digital currency community.
Every day in the future, digital currency enthusiasts will likely have to spend time identifying illegal transactions to avoid these things from happening. The U.S. Treasury Department has made a decision that cannot be changed.
A few weeks ago, the U.S. Treasury Department quietly posted a supplement to its FAQs on the website of the Office of Foreign Assets Control (OFAC), the agency responsible for overseeing U.S. economic sanctions. Language in OFAC’s plan to include ‘digital currency’ addresses on its Specially Designated Nationals and Blocked Persons (SDN) list.
This is going to be a big deal.
Banks and businesses of all types should check the SDN list to ensure they are not providing financial services to individuals, organizations and organizations designated as 'blocked' by the United States for involvement in terrorism, nuclear proliferation, theft, human rights abuses and other crimes. government.
Banks can legally freeze property they hold that is on OFAC's list and stop their transactions. If this is not done, the financial penalties may be more severe. Although most daily digital currency investors only know a little bit about the world subject to legal restrictions, operators of any form of financial business know that if you do not obey legal management, you may lose your business and property in an instant .
Never before has a specific digital currency address or property been listed on OFAC's list, although legal experts have understood for years that sending Bitcoin or other digital currencies to anyone on any of the SDN lists It would be illegal for Americans.
However, there is a big difference between closed funds in the financial world and those that can exist in the digital currency field. Peer-to-peer digital currency transactions cannot be blocked and regulated by third parties.
So an OFAC-designated digital currency fund is more likelyWill bring its external address for review, not the designated funds themselves.
Some experts in the digital currency industry believe that there will be a new era in the designation of digital currency funds; depending on their association with SDN addresses, a token is classified as clean, tainted, or It is an unknown era.
This may cause different price levels of coins on the same blockchain, with clean tokens being more expensive than those that are tainted or of unknown origin, and end the existence of digital currencies. There is substitutability.
The first is that we can expect that blockchain forensic tools will become increasingly valuable and more widely implemented, because digital currency transactions are designed to reduce the risk of users' transactions contaminating currencies.
It’s up to you
However, the most important part of a new era is the review of digital currency transaction addresses by financial institutions, which will be something the digital currency community itself will have to do: routinely block blocks Illegal transactions on the chain.
This is something the digital currency community doesn’t want to hear.
Digital currency experts often point to 'censorship resistance' as the most valuable feature of the technology, which allows anyone to store and send funds without any restrictions on government rights. In theory, this is a very powerful boost for freedom and democracy.
In practice, this technical capability is not extensible under the laws of most financial crime-related jurisdictions. While evading the actions of a corrupt government is a worthy goal, the digital currency community should be aware that remaining passive is ethically unacceptable, yet there is growing evidence of criminals and terrorists taking advantage of community freedoms.
In recent years, anti-money laundering (AML) compliance experts have focused on the conduct of the blockchain industry, encouraging digital currency businesses to go beyond the 'know your customer' (KYC) due diligence required by traditional financial institutions, and through Altering data on the blockchain to perform Know Your Transaction (KYT) analysis.
There are a number of startups that specialize in this kind of blockchain forensic work, working with other law enforcement agencies and corporate clients of large banks to conduct digital currency transactions. The companies' analytics tools are effective in fighting crime, but many voices in the blockchain community have criticized the tools -- saying they anonymize financial transactions on the blockchain. --To destroy privacy. However, much of the information from blockchain forensics is not publicly available. Typically, a corporate or government client is required to access this data.
However, OFAC’s listing of digital currency addresses increases the risk of KYT analysis.
This will be important for everyone involved in digital currency transactions, allowing them to verify the ‘legitimacy’ of the addresses they touch.
While it is likely that the number of designated addresses will start at the smallest (OFAC does not designate addresses lightly), even a small chance of violating sanctions will bringTo comply with the risk reduction, affecting the token buyers of the common people group.
An inadvertent transaction with a banned address, or an address that has been banned by a banned address, will be visible on the public blockchain ledger and may also taint the person's digital currency funds.
The only way to help daily users of digital currencies get out of SDN-affected blockchain platforms is to have real-time AML/KYT to gain insight into the flow of funds from various fund addresses. Judging from the current situation, blockchain analysis is only in silos and is only provided to financial companies and legal departments, so this method is simply impossible to implement.
Centralized AML
We need an open source platform where illegal activity is flagged and defamatory information is censored. We call it centralized AML on the blockchain.
I understand the need. As a researcher at a nonprofit national security think tank, I investigate incidents of digital currencies and illicit financing, such as Bitcoin terrorist financing in the Middle East. Our team used the free and public Blockchain Discovery website to analyze donations from these campaigns.
These tools are not as powerful as mechanisms like governments and banks that can use expensive specialized machine learning and algorithmic tools. Even through rigorous manual tracking and analysis of blockchain activity, I saw addresses that flagged transactions with terrorist funds, and there was no effective way to share my findings on the platform with everyday cryptocurrency users. They can see my 'flags', assess their accuracy as much as possible and keep their addresses uncontaminated.
The industry can help solve the problem
Two years ago, I suggested that cryptocurrency experts should set up their own gatekeeper groups to look for malicious activity on the blockchain, akin to 'white hats' How hackers flag viruses is the same as other cyber threats. The Treasury Department’s plans make it the most important thing now for the digital currency community to establish advocacy for self-regulation.
In addition to aggregating OFAC’s blacklist, a public crowdsourced blockchain AML tool can address an illegal financial threat that directly affects digital currency users: digital currency heists. This would allow victims of extortion or exchange hacks to voluntarily list their extorted or stolen tokens.
While this will not transfer funds back to their legitimate owners, it will make it more difficult to move or steal coins and have long-term consequences for digital currency theft.
Of course, for an AML platform that can self-monitor, there must be a way to review the list, so that inaccurate and illegal information will not be sent out. Otherwise, such a tool could be misused to mistakenly tamper with addresses and then financially persecute innocent people. But implementing AML on a blockchain platform is a more technical way to solve the problem, rather than finding reasons to refuse to find a better way.Law.
The first blockchain protocol, Bitcoin's breakthrough, was designed to decentralize methods to incentivize strangers to complete and affirm the authenticity of global public financial records.
Certainly, with all the attention, time, and money invested in a new product and service, those developing the technology should be able to devise ways to encourage retention of blocks. The chain is clean and untarnished.

⑺ What are the applications of blockchain electronic evidence in the evidence process

Take micro-copyright as an example. The evidence of micro-copyright goes directly to the Internet Court. When the user files a case in the Guangzhou Internet Court, he can Directly extract the files stored in the micro-copyright based on the evidence number, and automatically perform hash verification to confirm that the file has not been tampered with, and use the micro-copyright evidence as credible evidence.

All data stored through micro-copyright can be issued with a relevant certificate. Users can easily view the relevant electronic evidence by opening WeChat and scanning the QR code on the certificate. Information, evidence can be given directly in court.