What is expansion of blockchain

1. In one sentence, it is decentralization
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
in a narrow sense, blockchain is a kind of chain data structure that combines data blocks in chronological order in a sequential way, and it can not be tampered with and forged by cryptography
broadly speaking, blockchain technology is a new distributed infrastructure and computing method, which uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automated script code to program and operate data< Advantages:
1) the algorithm is simple and easy to implement
2) there is no need to exchange additional information between nodes to reach a consensus
3) it takes a lot of cost to destroy the system< Disadvantages:
1) waste of energy
2) it is difficult to shorten the block confirmation time
3) the new blockchain must find a different hash algorithm, otherwise it will face bitcoin attack
4) it is easy to generate bifurcation and needs to wait for multiple confirmations
5) there is no finality, and checkpoint mechanism is needed to make up for it.

2. The increase of blockchain network information is bound to need expansion, but it is not limited to a BTC public chain. No matter which public chain develops to a certain stage, it needs expansion technical support network. Therefore, it can be said that expansion is a necessary link for the implementation of blockchain scheme
the expansion of blockchain is the general trend, but there are differences in the specific operation. According to the different levels of blockchain architecture, the instry has proposed a number of expansion solutions: first, optimize the data transmission protocol for the underlying data layer of blockchain, do not change the upper structure of blockchain, and improve the scalability, such as bloxroute, the 0-layer expansion scheme of blockchain; The second is to change the data structure and consensus algorithm to improve the scalability of the basic protocol of blockchain, such as DAG (directed acyclic graph), fragmentation, dpos algorithm, etc; Third, aiming at the application level, such as side chain, sub chain, state channel lightning network and so on, part of the on chain transactions are transferred to the off chain execution to rece the on chain processing pressure and improve the overall efficiency.

3. yes. In 2017, the size of the capacity hit this "invisible wall.". Soaring costs have made bitcoin unreliable. Some users can't confirm their transactions even after waiting for many days. Bitcoin stopped growing. Many users, businesses, enterprises and investors have abandoned bitcoin. Its market share in many virtual currencies also dropped rapidly from 95% to 40%.

4. The format of the transfer contract is: Party A: (signature, address, ID card, etc.) Party B: (signature, address, ID card, etc.) specific terms: name, existing form, existing location, value and other delivery methods of the goods Dispute resolution can be divided into virtual currency transfer agreement

5. Slicing technology is one of the common methods used by developers to improve transaction throughput
in short, slicing is a partition method to divide computing power and storage workload in a point-to-point network. After slicing, each node no longer needs to deal with the transaction load of the whole network, It only needs to process the transactions in the partition (or partition)
just like the current blockchain, the information contained in the partition is jointly maintained by multiple nodes, thus ensuring the decentralization and security of the ledger. After the partition is enabled, everyone can still see all the information in the ledger, but people no longer need to process and store all the information

6. Yes~~~~~~~~~~~~~~~

7. Capacity expansion is a means that when a container or load is not enough to support or carry the demand of existing things, we can expand the capacity of the container or load to meet the growing demand, so as to relieve the pressure on the current container or load
at the beginning of the birth of bitcoin, Ben Cong, the founder of bitcoin, did not deliberately limit the block size. The maximum block size was 32MB, and the average block size was 1-2kb at that time
at that time, there are few bitcoin users and the transaction volume is not so large, which will not cause block congestion. However, since 2013, with the price of bitcoin rising sharply, there are more and more users, resulting in network congestion of bitcoin and rising transaction costs of users
up to now, there is a backlog of hundreds of thousands of transactions on the bitcoin blockchain. The average transaction cost of bitcoin is 376 times higher than that in September 2010. The processing speed of seven transactions per second has obviously been unable to meet the needs of users. The bitcoin community has begun to explore how to "expand the capacity" of bitcoin
by modifying the underlying code of bitcoin, the transaction processing capacity can be improved
there are two development and design schemes for bitcoin expansion, namely, the first layer and the second layer expansion technology
· the first layer of capacity expansion technology is to improve the blockchain itself, to make the blockchain itself faster and larger. Generally speaking, it is to change the content of the consensus part of the blockchain
· the purpose of the second layer expansion technology is to move the computing to the lower chain, that is, to solve the problem through the side chain technology
expansion protocol and outcome
expansion protocol generally needs the support of miners, which can be roughly divided into modifying block size, soft fork, hard fork, isolation witness and so on
take bitcoin as an example:
bitcoin is now divided into big block bitcoin cash (BCH) and isolation witness. Isolated witness is now recognized as bitcoin in the market, while big block coin is named bitcash. It can be predicted that in the future, bitcoin will focus on off chain trading. Including lightning network and side chain. These two new things are not mature at present, but they are highly expected by many people
bitcoin will develop a large number of isolated witness transactions and make more derivative technologies on the basis of isolated witness. Most likely, bitcoin will be pushed forward by technology
bitcash will focus on the development of monetary function, rece transaction friction as the main way, and gain more extensive users on the chain as the main development direction
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8. Although we have put forward various plans for capacity expansion, they can be basically divided into two categories: long-term rule group and short-term shelving group. The long-term model is idealistic and regular. Once it is finalized, there will be no more twists and turns. If bip101 / 103, a typical representative, sets a growth rule, there will be no adjustment. The short-term faction thinks that the future is unpredictable, fixed rules are too simple, and violent solutions are needed. They hope to set up a short-term plan for several years, which will be avoided for the time being and shelved until the future solution. The representative is bip100. However, e to the complicated voting process, it is simplified to bip102 / 109, etc., while bip248 is postponed to 2020. In recent years, it has simply doubled its growth
since June 2015, after more than half a year of repeated discussion, the long-term rule school has basically failed. In December 2015, after Pieter wuille proposed segregated witness at the bitcoin Hong Kong expansion conference, the expansion problem has even been simplified to upgrade to 2MB, but it has fallen into the debate about the implementation time
a seemingly simple technical problem of capacity expansion has caused the bitcoin community to spend more than half a year holding several global technical conferences and fighting countless private spats, but there is still no clear conclusion. The deep reason behind this is that the increase of block limit value can not really solve the problem of bitcoin expansion
however, some projects do build their own blockchains, such as Ethereum and decent.