Consensus on blockchain interconnection

1. 1. What is the technology of blockchain?

2. Introction to seven core technologies of blockchain operation on January 15, 2018
1. Blockchain links
as the name suggests, blockchain is a chain composed of blocks. Each block is divided into block head and block body (including transaction data). The block head includes the prevhash value (also known as hash value) of the previous block used to realize the block link and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the head of the previous block, and the random number calculation rule determines which miner can obtain the right to record the block
2. Consensus mechanism
blockchain is accompanied by the birth of bitcoin, which is the basic technology architecture of bitcoin. Blockchain can be understood as an Internet-based decentralized accounting system. A decentralized digital currency system like bitcoin requires the consistency of accounting of honest nodes without a central node, which needs blockchain to complete. Therefore, the core of blockchain technology is a consensus mechanism to reach a consensus on the legitimacy of transactions between indivials without mutual trust without central control
there are four main types of consensus mechanisms in blockchain: pow, POS, dpos and distributed consistency algorithm
3. Unlocking script
script is an important technology to realize automatic verification and contract execution on blockchain. Every output of every transaction does not point to an address in the strict sense, but to a script. A script is like a set of rules that constrain how the receiver can spend the asset locked on the output
the validation of transactions also depends on scripts. At present, it depends on two kinds of scripts: Lock script and unlock script. Locking script is a condition added to the output transaction, which is realized by a script language and located in the output of the transaction. The unlocking script corresponds to the locking script. Only when the conditions required by the locking script are met can the assets corresponding to the script be spent, which is located in the input of the transaction. Many flexible conditions can be expressed by script language. Interpretation script is similar to the "virtual machine" in our programming field, which runs in every node of the blockchain network in a distributed way
4. Transaction rules
blockchain transaction is not only the basic unit of a block, but also the actual effective content recorded by the blockchain. A blockchain transaction can be a transfer, or the deployment of smart contracts and other transactions
as far as bitcoin is concerned, a transaction refers to a single payment transfer. The transaction rules are as follows:
1) the input and output of the transaction cannot be empty
2) for each input of a transaction, if its corresponding utxo output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is the transaction not recorded in the blockchain, and each input of the transaction should come from the confirmed utxo. If it is found in the current trading pool, it is Shuanghua trading
3) for each input in a transaction, the corresponding output must be utxo
4) each input unlocking script must verify the compliance of the transaction together with the corresponding output locking script
5. Transaction priority
the priority of blockchain transaction is determined by the blockchain protocol rules. For bitcoin, the priority of a transaction to be included in a block is determined by the time when the transaction is broadcast to the network and the amount of the transaction. With the increase of transaction broadcast time on the network and the increase of transaction chain age, the priority of transaction will be improved and eventually be included by the block. For Ethereum, the priority of the transaction is also related to the transaction fee that the publisher is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority that the transaction is included in the block
6. Merkle proof
the original application of Merkle proof is bitcoin, which was described and created by Satoshi Nakamoto in 2009. Bitcoin blockchain uses Merkle proof to store transactions in each block. So that the transaction can not be tampered with, but also easy to verify whether the transaction is included in a specific block
7. RLP
RLP (recursive length prefix) is one of the main encoding methods of object serialization in Ethereum. Its purpose is to encode the sequence of arbitrary nested binary data.

3.

If bitcoin represents blockchain version 1.0, it proves to the world that digital currency can be realized. Then Ethereum represents blockchain version 2.0, which lets you know more about the play of blockchain, decentralized applications and smart contracts. In 2018, blockchain will enter the stage of 3.0, application and scenario landing will be the core of blockchain, and blockchain based applications in various instries will spring up, which will be the early dividend period of the last stage of blockchain development. The demand for talents driven by the application of blockchain technology has become increasingly large. Blockchain technical talents have become the new professional talents, which are highly competitive, and also have enviable high salaries

whether to form a meaningful large-scale consensus: one of the outstanding advantages of blockchain is that it can effectively form a large-scale consensus by opening account books and notifying the whole network. At present, there is no need to form a network wide consensus for many projects. Some projects are just for crowdfunding and token issuance. The blockchain consensus of projects is meaningless. Does this model have network effect: network effect means that a project will become more and more valuable with more and more users of the project, because the value of the project is not in the users themselves, but in the connection network between users. Bitcoin is a typical example. The more user nodes there are, the more links between nodes will grow exponentially, and the whole ecosystem of bitcoin will be more valuable

of course, in addition to these points, there are many basic principles to judge the project, such as effective incentive mechanism, strong team, project solving pain points, and so on

4. In essence, blockchain is a decentralized ledger system, which has the characteristics of decentralization, openness, non tampering information and programmability. It can be used as the underlying storage and transmission protocol of value Internet. Blockchain is expected to lead us from personal trust and institutional trust to the era of machine trust. Consensus mechanism is the core of regional chain construction. Digital currency is just the beginning. Blockchain can change more, reshape the world's trust system, and solve many problems of high trust cost in the past
there is a core difference between blockchain and Internet: the value of underlying protocols and upper applications of blockchain and Internet are completely reversed. It mainly comes from the two core features of blockchain:

the first feature is that zero knowledge proof changes the ownership of data. In other words, the user's personal data on the blockchain belongs to the user and does not need to be provided to the application and stored on the central server. Then the core support "data" behind the market value of Internet application layer services, such as bat, will lose its original value in the field of blockchain
another feature is the economic incentive model brought by token, which gives high value to the underlying protocol. In the Internet era, no one pays for HTTP protocol, no one pays for sending and receiving email, and no one pays for Google's search service.

5. The reasons are as follows: 1. The United States does not allow the suspect to be punished personally, that is to say, if the person does not speak, there is no way! American suspects have the right to silence. Therefore, no one can help him if he doesn't speak. 2. In the United States, there is always a law of egg pain, which can be used to account for the whereabouts of the victims and demand a light sentence! That's why the suspect didn't speak. I didn't hurt anyone, no body! So this can be a lighter sentence. 3. What's more painful is that there is no death penalty in the state where Zhang Yingying went. The reason why the case is not closed is that there are no bodies! According to the law of the United States, it may be the one who got off the bus half way and lost himself!! Because there's no body! Therefore, only Chinese law is just!

6. TCP (transmission control protocol) and UDP (User Datagram Protocol) belong to transport layer protocol. TCP provides reliable data transmission in IP environment, including data stream transmission, reliability, effective flow control, full plex operation and multiplexing. Through connection oriented, end-to-end and reliable packet delivery. Generally speaking, it is to open up a well connected channel for the data to be sent in advance, and then send the data; UDP does not provide reliability, flow control or error recovery for IP
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies. The so-called consensus mechanism is a mathematical algorithm to establish trust and obtain interests between different nodes in the blockchain system. Blockchain is equivalent to the Internet in the 1990s. Bitcoin, Puyin and other digital currencies are applications of blockchain.

7. Brief introction: Beijing Internet consensus information technology Co., Ltd. is founded by core members of domestic famous security teams, such as network security, 360 enterprise security, and Jianxue Research Institute. Used to export security capabilities for Internet Unicorn companies such as Microsoft, Google, 360, Tencent, Facebook, etc. We set up the John wick lab to build the most comprehensive and in-depth service solution for the blockchain and protect the ecological security of the blockchain. Adhering to the core concept of "know how to attack and be good at defense", the company provides deep penetration testing, intelligent contract audit, overall security solutions, third-party monitoring and early warning, and other services around the blockchain ecological environment Threat Intelligence output and other services
legal representative: Fu Dongliang
time of establishment: June 26, 2018
registered capital: RMB 11111110000
enterprise type: limited liability company (invested or controlled by natural person)
Company Address: 0256, floor 4, building a, building 24, yard 68, Beiqing Road, Haidian District, Beijing