What is the blockchain _ simple and easy to understand introduction
Blockchain is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. The so-called consensus mechanism is a mathematical algorithm for realizing trust and acquiring rights between different nodes in the blockchain system.
Blockchain is an important concept of Bitcoin. The currency is linked to the Internet Finance Lab of Wudaokou Finance College of Tsinghua University and the “2014-2016 Global Bitcoin Development Research Report†released by Sina Technology. The blockchain is bitcoin. The underlying technology and infrastructure. Essentially a decentralized database, as the underlying technology for Bitcoin. A blockchain is a string of data blocks generated using cryptographic methods. Each block contains information about a bitcoin network transaction for verifying the validity of its information (anti-counterfeiting) and generating the next block.
In a narrow sense, a blockchain is a chained data structure in which data blocks are sequentially connected in a chronological order, and cryptographically guaranteed non-tamperable and unforgeable distributed ledgers.
Broadly speaking, blockchain technology uses blockchain data structures to validate and store data, use distributed node consensus algorithms to generate and update data, and use cryptography to ensure data transmission and access security, using automated scripts. The code consists of a smart contract to program and manipulate data in a completely new distributed infrastructure and computing paradigm.
The blockchain is the underlying technology of Bitcoin. Before it was crazy, what happened to the story, and promoted it to be known? At the blockchain technology forum sponsored by Luyun District Chain, Ding Hao, CEO of Luyun District, introduced the past and present of the blockchain. Ding Hao graduated from Sichuan University and Huazhong University of Science and Technology and worked on Huawei's core network for user data management solutions.
2008 is precisely the time when the global economic and financial crisis is at its worst. The financial crisis has reached a climax in the United States and spread to the world.
At the end of 2008, Nakamoto published a nine-page white paper on his research on the electronic cash system. In early 2009, Nakamoto seized the first block of Bitcoin, the Genesis Block, on a small server in Helsinki, Finland, and published a news report on the rescue bank on the front of the Times. The title is written in the Genesis block, which also means that Bitcoin was born.
Bitcoin application blockchain 1.0
In January 2009, Nakamoto introduced an untested revolutionary new concept to the world: decentralized peer-to-peer online currencies that maintain value without any asset guarantees, intrinsic value or central issuers.
Think of the blockchain as a public book of bitcoin, this book:1. Stored on each bitcoin node of the Internet, each node has a complete backup.
2. It records all bitcoin transfer transactions since the birth of Bitcoin.
3. The ledger is stored in a partition block, and each block contains a part of the transaction record. Each block records the identity of the previous block, forming a chain structure, hence the name blockchain.
4. When you want to initiate a bitcoin transaction, you only need to broadcast the transaction information to the network. The miner (image) records your transaction information into a new block and links it to the blockchain. finished.
Clarification of three key issues
1. If you only have ten coins, and you actually initiated a transaction for 20 coins, what should I do?
Because all bitcoin transaction records are recorded on the blockchain, you only need to go back to all the historical transactions associated with your account to know how much balance you have on this account. The balance will not refuse to record your trade.
2. How to ensure that your account is not replaced by impersonation?
Digital signature technology. Each Bitcoin account has a public and private key. When you initiate a transaction, you use the private key to sign the transaction information. After the miner receives the information, check the signature with the public key.
3. So many miners, how do you decide which miner will generate the next block?
Nakamoto has designed a mathematical problem that will take a lot of computer CPU time to get the answer, and each time the answer will be used as the initial condition for the next calculation. The miners all over the world come together to calculate the problem. Whoever answers first, he can use this answer to generate a new block and broadcast it to the network.
Thinking carefully about this system will reveal that it is almost invulnerable. Users can't make Bitcoin out of thin air, they can only mine and get it; secondly, they can't falsify transactions, and they can't control accounts that don't belong to you. Once the transaction is confirmed, it can hardly be cancelled.
It is said that "almost" is because there is a "51% attack". The 51% attack conditions are very demanding and will not expand here.
The introduction of smart contracts adds autonomous functionality to blockchain technology
In 2010, when Bitcoin's built-in scripting system was discovered, someone posted on bitcointalk expressed surprise and puzzled: "The bitcoin script makes me a little nervous, which is too complicated, and complexity is a natural enemy of security." This is not someone else, it is Gavin Andresen who later became the successor of Nakamoto.
Nakamoto is so responsive to him:I hope that Bitcoin will have a stable architecture in version 0.1, and there is no need to make the underlying changes in the future. In the process of designing Bitcoin in the past few years, I found that only the use of a scripting system can complete the various types of complex transactions I wish to support - secured transactions, joint contracts, third-party arbitration, multi-party signatures, and so on.
Today, perhaps Nakamoto will say directly: "Bitcoin needs scripts, and with scripts, there is a smart contract."
This post is only a short nine, but it can be called an important dialogue in the history of blockchain technology development.
On the 8th floor, someone asked "Does the bitcoin scripting system mean that users can issue custom assets?". This person ID is bytemaster, and later it created a bit stock that can issue user-defined assets.
The birth of Blockchain 2.0: Smart Contracts and Ethereum
Blockchain 1.0 supports the smart contract script system is not perfect, which makes its application in the non-financial field very difficult - mathematical computing has swallowed up 80% of the entire network computing power, each block is only 1M in size, can record information Very limited. As a result, Ethereum has made significant improvements on the Bitcoin blockchain:
1. Improve the scripting system so that smart contracts can be applied in various non-financial fields;
2. Balance accounts to achieve more detailed account control;
3. The underlying protocol remains simple.
In essence, the Bitcoin network is actually a distributed database, and Ethereum goes a step further and can be seen as a distributed computer. Blockchain can be thought of as computer memory, smart contracts are programs, and Ethereum miners are responsible for computing and serving as CPUs. People must pay for the use of this distributed computer.
Smart contracts are essentially "contracts" + "courts"
The traditional paper contract only stipulates the content of the contract. The enforcement of the contract depends on the judicial system. The "smart contract + blockchain" makes the contract content and money appear in the form of computer code, so the enforcement is also written into the code. Without a third party.
Expansion of Blockchain: Trust in Value Internet
Nodes around the world work together on smart contract codes, and the underlying algorithm (PoW/PoS) that is agreed upon ensures the credibility of the results, so the blockchain is particularly suitable for the following scenarios:
• Exchange of value information
• Automated execution of contracts (autonomy)
Value Internet is different from information Internet in that it delivers valuable information, but the first thing that needs to be solved is trust.
The blockchain is born of bitcoin. The general public simply regards bitcoin as a currency, but fundamentally, the blockchain is a value transfer protocol. The blockchain is more similar to the Internet TCP/IP protocol than the digital currency in the usual sense. However, the TCP/IP protocol is designed for the information Internet, and the blockchain provides a theoretical basis for the value Internet.
It can be said that the problem of trust exists everywhere, and it can be solved by blockchain.
But in the value exchange on the Internet, there are three problems to be solved: one is to ensure the uniqueness of value exchange; the second is how to establish the trust relationship between the two sides of value exchange? The third is how to ensure that the commitments of both parties can be automatically implemented by relying on the network's autonomous mechanism (smart contract) without the involvement of trusted third parties.
Simple and easy to understand introduction blockchain
The blockchain was born from Nakamoto's bitcoin. It is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc. It is essentially a decentralized distributed ledger database. For the sake of understanding, let's take a look at the centralized centralized trading model, as shown below.
In this process, although you are dealing with the seller, the deal involves third parties other than you and the seller, Alipay, and the transactions between you and the seller are all around Alipay. Therefore, if the Alipay system has a problem, it will cause the transaction to fail. The decentralized approach is much simpler. You only need to exchange money and mobile phones with the seller, and then you are OK. It can be seen that decentralization is more convenient and there is no need to worry about leaking your information. If there are tens of thousands of transactions in progress, decentralized processing will save a lot of resources. Decentralization is the subversive feature of blockchain technology. It does not require a centralization agent, and realizes a point-to-point direct interaction, making the information interaction mode of high-efficiency, large-scale and non-centralized agents a reality. Blockchain technology is moving from "niche players" to "popular lover": the recent domestic Internet companies' actions on the blockchain are frequent: Thunder's "chain", stormy "BFC" points, Renren Recently released "RRCoin", 360 announced the launch of the world's first blockchain-based secure shared cloud platform and so on. Let it gradually move to the application level.
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