[PaperNote] Web3 Direction

Web 3 The direction of the paper reading notes .
Bitcoin、BlockStack、Ethereum White Paper All three articles can be read from Mit 6.824 Find .

Bitcoin: A Peer-to-Peer Electronic Cash System

Put forward

Digital signature can satisfy “ Online direct transactions between the two parties without going through third-party economic institutions ” The requirements of , But it can't prevent double-spending The problem of . meanwhile , Intermediary digital currencies cannot be irreversibly traded , At the same time, it needs to pay intermediate fees .
double-spending It refers to the risk that cryptocurrency may be used twice or more . If certain conditions are met , The transaction information in the blockchain can be changed .
To solve these problems , A point-to-point scheme is proposed , Hash through network timestamp , Form a record that cannot be changed without proof . The longest chain is not just proof of the deal , And from the biggest CPU Calculation pool .

transaction

In addition to the trading system shown in the figure below , Need a consensus system , Let most nodes agree that each transaction is the first node to arrive .

Timestamp server

The initial idea was to use a timestamp hash with a large number of items , And publish it .

Setting up a distributed timestamp server requires something like Hashcash Proof of work system , Prove that the system passes cpu Calculate some hash values of previous transactions .

The transaction process is as follows ：
1） Broadcast new transactions to all nodes .
2） Each node collects new transactions into blocks .
3） Each node finds proof of work for this block .
4） When the node finds the proof of work , It broadcasts blocks to all nodes
5） Nodes only accept blocks if they are valid in all transactions and are not spent
6） The node expresses its acceptance of the block by using the hash of the accepted block as the previous hash to create the next block in the chain

Incentives

The first transaction in the block is a special transaction , This transaction initiated a new coin owned by the founder of the block . This increases the power of nodes to support the network , It also provides a method of allocating coins to the issue , Because there is no central authority to publish them . A steady increase in the number of new coins is similar to a gold miner spending resources to increase circulating gold . under these circumstances , The time and power spent is the cost .

Space recycling

Blockchain uses Merkle Tree Store transactions , So you can discard past transactions to save space .

Privacy level

Anonymous by public key , It can interrupt the information flow of the blockchain , Privacy protection .