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⑴ What technology development is needed for blockchain

What technology development is needed for blockchain:
1. Blockchain theory: Blockchain developers need to Being familiar with the theoretical knowledge of blockchain is the most basic requirement for a blockchain developer. The content includes blockchain network architecture, decentralization and other related application technologies. Expanding technical theory is mastery of Ethereum development.
2. Smart contract: Smart contract is a string of codes that blockchain developers need to write in blockchain programming language. It is a trust mechanism developed after imagining logic according to different scenarios, aiming to eliminate the intervention of third parties. Create an efficient and high-trust blockchain network. Blockchain developers need to realize automatic execution of this string of code, and the operation effect is irreversible.
3. Cryptography: Many blockchain application scenarios have high encryption, and point-to-point encryption mode is a characteristic of cryptography. By studying cryptography, blockchain developers understand encryption concepts such as wallets, keys, and a wide range of encryption and decryption technologies
4. Distributed architecture: Blockchain developers must understand the functions of distributed architecture and networks . Decentralized network is the foundation of the blockchain architecture. The transmission of information in the blockchain network must follow a decentralized approach so that everyone can enjoy the same network rights.

⑵ What are the core blockchain technologies of blockchain technology?

What is the hottest Internet topic at the moment? You don’t need to explain it to the editor to know that it is the blockchain. Blockchain technology, but 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 , because it 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 function is easy to verify, but it is Very 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 an asymmetric encryption algorithm, while symmetric encryption uses the same key in the encryption and decryption processes.
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 computing.Law.
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 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 use in public chains. If you build a private chain, since there is no trust issue with verification nodes, you can useIt is more appropriate to use POS; and due to the existence of untrustworthy local nodes in the alliance chain, it is more appropriate 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 the contract by checking external data sources and confirming that specific trigger conditions are met.
The above is what blockchain technologies the editor has brought to you? All content of the introduction to the core technology of blockchain.

⑶ What are the blockchain technologies?

The concept of blockchain can be said to be very popular. At the Internet Finance Summit, no one said that blockchain technology is out. What is chain technology?

Blockchain technology can be either a public classification (anyone can see it) or a permissioned network (only permissioned people can see it), solving supply chain challenges. Because it is An immutable record, so it is shared among network participants and updated in real time.

Blockchain technology - data layer: Designing the data structure of the account book

Core technology 1. Block_ _;Chain:

Technically, a block is a data structure that records transactions, reflecting the capital flow of the transaction. The transaction blocks that have been reached in the system are connected to form the main chain, and all nodes participating in the calculation are Records the main chain or part of the main chain.

Each block consists of blocksThe block header is composed of a 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 includes the current version number, the previous block address, and a timestamp (recording the time when the block was generated. Accurate to the second), random number (recording the answer value to the mathematical problem related to decrypting the block), the target hash value of the current block, the root value of the Merkle number source and other information. From a structural point of view, most of the functions of the blockchain are Implemented by block header.

Core technology 2. Hash function:

.

The hash function can convert data of any length from the Hash algorithm to a fixed length The principle of the code is a one-way hash function based on cryptography. This function is easy to verify, but difficult to interpret. The industry usually expresses it in the form of y=hash(x). This hash function implements the hash operation of x. Value y.

Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384, SHA-512, etc. Taking the SHA256 algorithm as an example, if you input any data into SHA256, you will get 256 Bit Hash value (hash value). Its characteristics: the same data input will get the same result. A slight change in the input data (for example, 1 becomes 0) will get a completely different result. The result is measured. Forward calculation (data calculation The corresponding Hash value) is very simple. Reverse calculation is extremely difficult and is considered impossible under current scientific and technological conditions.

Core technology 3. Merkle tree:

Merkle tree is A hash binary tree can quickly verify the integrity of large-scale data. In the blockchain network, Merkle V Dan Lu Xing Wei Wei Hui Zai Pan⒌ Mou Xi Ji Ceng Mou_erkle trees.

Core technology 4. Asymmetric encryption algorithm:

Asymmetric encryption algorithm is the secret of the key The method requires a key and a key. The public key and the private key are a pair. If you use the public key to encrypt data, you can only use the corresponding private key to decrypt it to obtain the corresponding data value. If you use the private key to sign the data, you can only use the corresponding The public key verifies the signature and verifies that the sender of the information is the owner of the private key.

Since encryption and decryption use two different keys, the algorithm is called an asymmetric encryption algorithm, while symmetric encryption is used in encryption The same key is used in the decryption process.

Blockchain mitigation technology - network layer: achieving centralization of charging nodes

Core technology 5, P2P network:

P2P network (peer-to-peer network), also known as peer-to-peer technology, is an Internet system without a central server and a user group exchanging information. Unlike a central network system with a central server, each client in the peer-to-peer network is a node , also has the function of a server. Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of centralization and strengthening.

Blockchain technology-consensus layer: allocate the task load of charging nodes

⑷ Application models of blockchain

I think blockchain applications can be divided into three models:

1) Build ecological business collaboration. Abbreviated as C, the focus is Collaboration. The key points are to distinguish the main roles in the ecology and design a role-based incentive mechanism. If the collaboration is done well, it will become a self-ecological organization DAO (de-centralized autonomoue organization). This is the most ideal scenario. Of course, in actual scenarios, complete decentralization is not very realistic. The blockchain ecology can have a center, and can even be based on mature commercial organizations. By building an ecosystem layer model, the enterprise can be transformed without changing the In the case of core product and service models, the boundaries of interests of the enterprise are downplayed and flexible collaboration is formed with external resources.

2) Establish cross-organizational data and process connectivity. D for short, data sharing is the core of this model. Based on digital sharing, process links are realized to achieve business automation or automated value iteration. This is what is commonly referred to as the combination of blockchain and AI. AI requires iterations of data and automation. Blockchain is the basis for data sharing.

3) Related to asset trading, referred to as T, through digital mapping, a new model of asset trading and management is realized, especially to improve transparency and transaction efficiency. The reduction in credit costs brought by the blockchain can reduce the granularity of transactions, bring better asset liquidity, and can also aggregate and utilize micro-values ​​that could not be cashed in before. The distributed transaction model of the blockchain allows end-to-end transactions to be independently designed and more flexible.

I personally think CDT is the main paradigm of blockchain applications.