Getting Started with Blockchain

What is blockchain?

Literally: the blockchain is a chain composed of small blocks that record various information, similar to when we stack bricks, and they cannot be removed after stacking. There are also various information written on the brick, including: who stacked it, when it was stacked, what material the brick is made of, etc. You can't modify this information.

From the computer point of view: Blockchain is a special kind of distributed database. A distributed database is to put data information on each computer separately, and the stored information is consistent. If one or two computers are broken, the information will not be lost, and you can also view it on other computers.

The blockchain is distributed, so it has no central point. Information is stored in all nodes that join the blockchain network, and the data of the nodes is synchronized. A node can be a server, laptop, mobile phone, etc.

What you need to know is that the data stored in these nodes is exactly the same.

Blockchain Features

Decentralization : Because it is distributed storage, there is no central point. It can also be said that each node is a central point, and applications in life do not require third-party systems (banks, Alipay, real estate agencies, etc. belong to third parties) ).

Openness: The system data of the blockchain is open and transparent, and everyone can participate. For example, when renting a house, you can know the previous rental information of the house and whether there have been any problems. Of course, some personal private information here is Encrypted.

Autonomy: The blockchain adopts consensus-based specifications and protocols (such as a set of open and transparent algorithms), and then each node operates according to this specification, so that everything is done by machines, and there is no human element. The trust in "people" is changed to trust in machines, and any human intervention will not work.

Information cannot be tampered with: if the information is stored in the blockchain, it will be permanently stored, and there is no way to change it. As for the 51% attack, it is basically impossible to achieve.

Anonymity: There is no personal information on the blockchain, because these are encrypted and are a string of numbers and letters, so that your various ID information and phone numbers will not be resold.

block structure

A block contains two parts:

1. Block header (Head): record the meta information of the current block

2. Body: actual data

Contains data as shown below:

How Blockchain Works

Let's take a transfer as an example:

At present, our transfers are centralized, and the bank is a centralized ledger. For example, account A has 400 yuan, and account B has 100 yuan.

When A wants to transfer 100 yuan to B, A needs to submit a transfer application through the bank. After the bank's verification is passed, 100 yuan will be deducted from A's account, and 100 yuan will be added to B's account.

After calculation, after deducting 100 from account A, the balance is 300 yuan, and after adding 100 to account B, the balance is 200 yuan.

The steps of transfer on the blockchain are: A wants to transfer 100 yuan to B, A will tell everyone the information to be transferred on the Internet, and everyone will check whether there is enough money in A's account to complete this. Transfer, if the verification is passed, everyone will record this information in the blockchain on their computer, and the information recorded by everyone is synchronized and consistent, so that A can successfully transfer 100 yuan to B's account. superior. It can be seen that there is no bank in the middle.