Hi, friends, good morning, the official account has been temporarily updated for the past two weeks. Because of the sudden emergency in my hometown, I went back for a while, and after I came back, I rushed to release the release requirements, and finally released the release successfully yesterday. Today, I will share an additional article on blockchain technology from Mr. Feng Yuangui. If you invest in stocks or buy digital currency, you must have heard of blockchain, but aside from the investment perspective, from the perspective of learning technology, you are right How much do you know about blockchain? If you are interested in learning about blockchain technology, you may wish to read this article. If you feel unfulfilled, you can join the blockchain technology live exchange group at the end of the article and learn together. (You can also forward it to your classmates who need to learn)
I wrote an article " Technology Trend Forecast in 2018 " on December 26, 2017. I wrote this about blockchain:
Blockchain is an invention that can change the world. The blockchain originated from Bitcoin, but it is not limited to the currency circle. Blockchain technology is a practical solution to problems such as storage, verification and data protection. Blockchain can be thought of as a decentralized, extremely secure database. More professionally, blockchain is a distributed peer-to-peer cryptography-based shared ledger, which can be widely used in financial services, insurance, medical care, government and other fields. 2018 should be the year when blockchain technology takes off and matures.
Unexpectedly, at the beginning of 2018, blockchain technology is like the highest flame on the top of the flame on the road to the west. Many people will say that it is so popular, how come I don't know. In fact, Bitcoin is the most popular in 2017, and the upward curve of the blockchain really only happened in January. Just look at the WeChat index of the blockchain to know:
When a wave hits, the best way is to face it and find out what's going on, rather than ignore it, or simply pretend it didn't happen. I have read some relevant materials recently, and if I have a more specific understanding, I will write a vernacular article. Reading time is about nine minutes.
What exactly is blockchain? People who don't know the truth generally go to Wikipedia, which says this:
Blockchain (English: blockchain or block chain) is an intelligent peer-to-peer network that uses distributed databases to identify, disseminate and record information, also known as the Internet of Value. In 2008, Satoshi Nakamoto proposed the concept of "blockchain" in the "Bitcoin White Paper", and in 2009 he founded the Bitcoin social network and developed the first block, the "genesis block".
After reading it, did you find that it is all Chinese characters, why can't you understand what it means? So the concept of blockchain still needs to be explained. First of all, it needs to be clear that the blockchain is a set of protocols and specifications, which is a protocol in English, not a specific code or project. After understanding this protocol, you can implement it based on different languages and technologies, which is no different from defining a set of APIs and then implementing them based on different technologies.
But the blockchain may be different things in the eyes of people in different fields. Different angles lead to different conclusions. People in the financial field will think that the blockchain is a distributed ledger, a distributed and decentralized accounting system. People who do security and cryptography will say that blockchain is a peer-to-peer network built on cryptography. And our programmers understand the blockchain technology, and will think that this is not a distributed database that guarantees eventual consistency.
Accounting system
For ordinary people, the accounting system is the easiest to understand. Let's start with the ledger. For example, when we do business together, we always need to have an account book. Initially, this account book is managed by the accountant. But if one person manages, there will always be unbalanced reconciliation (such as misappropriation), so everyone starts to take turns. There is also a problem with this method. During the period of someone keeping the ledger and accounting, once the data is lost or the ledger is damaged, the real reason will not be clear. In the end, everyone decided to use a new accounting method. Everyone has their own account book. Anyone who changes his account book must tell everyone else, and others will also record a sum in their own account book. As long as someone finds that the new accounts are wrong, they can refuse to accept them. In the end, the accounts agreed by the majority shall prevail.
This is a distributed decentralized accounting system. However, there will be problems with this practice for a long time. Some people remember it every day, and some people are lazy and don’t remember it, which will cause unfairness. So everyone decided to roll the dice every morning, and based on the points to decide who would record the account for the day, others would check it and copy it if there was no problem. And, the bookkeeper of the day gets a little reward (this is mining).
Decentralized distributed database
The above accounting system is implemented with software technology, which is a decentralized distributed database.
什么是中心化，早期互联网大都采用 CS 架构，一个服务器 N 个客户端，Client 和 Server 之间进行通讯，系统可靠性严重依赖 Server，这叫中性化。
随着业务复杂度的增加，服务器端也开始分拆，横向和纵向扩展，读写分离等等，这就是我们常用的分布式架构系统，系统可靠性依赖分布式系统的热备份和容灾恢复能力。这时候服务器虽然分布了，但依然是中性化的。大部分商业公司都采用类似的架构和模式。
去中心化是怎么回事呢？就是数据库不属于任何机构和管理员。只要服务器端被某个机构或管理员控制，就存在宕机或数据篡改的风险。区块链和 P2P 的网络通信技术最终实现了去中心化。区块链的作用就是存储信息，可以认为是一个数据库，而任何人都可以通过 P2P 网络架设服务器，接入区块链网络，成为一个节点。这下人人平等了，大家都是 Server，也就没有了 Server，每个节点既是生产者也是消费者。
你可以向任何一个节点读写数据，一旦写入就是历史，最后所有的节点都会同步数据，保证「账本」的一致性。
区块链是没有管理员的，也不需要人工审核和干涉。那人人都能写数据，数据的可信度怎么保证呢？数据被篡改了咋办？别担心，P2P 网络只是进行信息通讯，保证数据安全的还有共识算法和加密算法。
共识算法
关于共识算法、拜占庭将军问题，大家可以参考这一篇文章，很长，但容易看懂。
分布式一致性与共识算法（https://draveness.me/consensus）
简单来说，共识算法就是保证少数服从多数，也就是我在记账系统中写过的「最后以大多数人一致的账目为准」。大多数人认可的事情，就是事实。这种规则听起来挺吓人的，比如我们常常在文学作品和历史经验中知道，真理往往掌握在少数人手里。但是在 P2P 的网络里，有无数的节点，要想大部分节点一起作恶，除非这些节点都被某个组织控制了。这种可能性虽然不是没有，但几率非常小。
总的来说，共识算法解决的是对某个提案（Proposal）达成一致意见的过程。提案的含义在分布式系统中十分宽泛，包括多个事件发生的顺序、某个键对应的值…等等，可以认为任何需要达成一致的信息都是一个提案。
有了共识算法和相关的加密算法，就可以保证数据的安全性和一致性。
为什么会挖矿？
谈到比特币，大家耳熟能详的就是挖矿和矿机这种事。那为什么会挖矿呢？挖矿其实是一种激励和竞争机制。
在区块链系统中，总有些节点被选中进行数据整理、验证、打包，并把相关的改动广播出去，这个工作还是挺耗资源的，所以会有奖励机制。负责打包的节点会获得系统的奖励，类似积分，对于比特币系统来说，就是奖励比特币。有了奖励，很多节点都希望获得这样的奖励，于是有些区块链系统，比如比特币就会设计出一种竞争机制，让各个节点凭借自己的算力和资源去抢，能抢到这个数据打包的机会，就会获得奖励，也就是比特币。这个竞争的过程就是挖矿。
什么是算力呢？就是计算机每秒产生 hash 碰撞的能力。也就是说，手里的矿机每秒能做多少次 hash 碰撞。算力越高，获得的奖励越多。
区块链的未来
很多人觉得区块链的唯一应用就是发行虚拟货币，最近国内外市场也是烽烟四起，比如超过百年历史的伊士曼柯达公司宣布推出基于区块链技术的「柯达币」（KodakCoin）和 KodakOne 平台，让全球的摄影师能够更好的控制图片的版权和交易。然后股价就飙升了……
了解了区块链的技术特点，我们就知道，区块链的能力远不止虚拟货币领域，未来的 金融服务、物流、保险、医疗、共享经济、智能合约领域，应该都会有区块链的身影。
繁华落尽，洗尽铅华，所有的技术都将经历时间的洗礼。历经爆发期、衰退期并进入成熟期的技术，才是真正能具备生命力的技术。
想详细了解区块链技术，一篇文章是远远不够的，推荐一节免费直播课给感兴趣的读者。
分享者是冯贵彬：
Technical Director of LinkJapan IoT New Business Research Office, Beijing Meteorological Bureau Radar Communication Research Office from 2006 to 2012, and Beijing Kangkang Shengshi Information Technology Co., Ltd. in charge of BLT communication development from 2012 to 2015. Currently working at LinkJapan Inc in Japan. Main research directions: IoT/big data, deeplearning, self-driving, etc.
Live class content:
1. What is blockchain?
Introduce the concept and basic technical characteristics of blockchain.
2. The development history of the
blockchain Introduce the problems solved by the blockchain and talk about the development history of the blockchain
3. The basics
of blockchain introduce the operation principle, public chain, private chain, alliance chain, commonly used encryption algorithms and other mechanisms, as well as the role of forks and miners in the chain
4. Disadvantages of blockchain
5. Typical application of blockchain - digital currency headed by Bitcoin
7. The future development of blockchain technology and application of
blockchain 1.0 era ,
blockchain 2.0 era,
blockchain 3.0 era
Live broadcast time : 20:30 on the evening of January 24, 2018
Registration method : long press to identify the QR code
Or add [Sky Blockchain Technology Sharing Group] group number: 695649062
Oh, by the way, I owe readers an article about Android push before, and I will add it this week. If you have any ideas about the blockchain and digital currency mentioned in this article, you are welcome to leave a message below. I have purchased a certain amount of digital currency myself, and currently have a certain entry-level understanding of blockchain. If I accumulate a similar amount later, I would like to write an article about blockchain.