1. blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies
blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
extended data
according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:
1. The blockchain with the whole network open and without user authorization mechanism is called public chain
2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain
3. All the nodes in the network are in the hands of one organization, which is called private chain
alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain
blockchain features
1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes
5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously
2. I was in Suning on January 15 to see a mobile phone. I was originally planning to buy a Samsung. The assistant introced the brand of Xianfeng. My friend who went with me said that Xianfeng was a Japanese brand, and it was OK to make audio procts before. After a look, I found that the appearance and configuration were good, but I was not sure about the new brand. The assistant of Suning promised me that if there was a problem in 30 days, it would be replaced and returned in 7 days, He also said that it was the group purchase price on the same day, so he was excited. He thought that it would be guaranteed if the mobile phone was replaced in 30 days. However, the flash screen appeared on the 15th day when the mobile phone was just bought back. So he called to inquire. The 400 phone said that the mobile phone was e on the 29th, and could not be replaced, but could only be repaired. Later, he made several calls, and a customer service said that today was the last day, and it could be replaced when the reaction was good, But I had to take it tomorrow. At first, I said that I would go to work tomorrow. I would see if it was OK to take it on February 3. I said no, it must be tomorrow. So when I called on the 31st and said that I would take my mobile phone for inspection, they made an excuse to say that it could not be changed. I said that yesterday, I said that the reaction on the 15th day could also be changed. At that time, I promised to change it for a month. Then I said for a long time and asked me, So in the end, let me take it first. I repeatedly explained that I would go after work, and don't say you're off work at that time, so the customer service said no, I've already received it according to the schele. Sure enough, when I took my mobile phone to Shenzhen Huaqiangbei Qunxing Plaza store to find the relevant personnel after work, they gave me the reply that it's all off work, bring it tomorrow, I'm really out of breath. When people in Suning saw that I was a little difficult to bully, they said to help me find out. I said I wanted to see the store manager. After a while, a man came to the store manager. It was said that he was the store manager. I said that I would play the recording to you first. I didn't want to say any more, because I promised to change it for a month and said that I had no evidence, so I made preparations in advance and recorded all the calls. I played a recording. Later, the store manager called and said that if there was a problem, he would change it for me. At that time, the service center received my mobile phone. This time, they said something again. Today (February 1), when I called to ask why, a woman answered the phone and said that she was the front desk. After asking about the situation, I said that she was sent for inspection and replacement, The woman said that I think your mobile phone is for repair, not for inspection. I said I want to know why. He said I'm not a master. I don't know. I asked the bad woman for a master's phone. The bad woman said, why should I give you the master's phone? What qualifications do you have? I'm so angry. I said you don't know if I can ask Shifu? And he said, do you have a cornet? I didn't want to argue with him, so I asked her job number, so he said that you are not qualified to know my job number. Why should I tell you. I didn't want to get angry with this bad girl, so I had to hang up. After a few minutes, the master called me and said that my mobile phone had not been checked. He only helped me upgrade the software, but also didn't dismantle it. So I asked, didn't I send it for inspection? The flash screen of mobile phone is serious. Why not check it? He changed his statement again. It's no problem. You don't need to repair it. Now you come here to have a look. It's no problem at all. I said that if it's not checked, how can you know if there's a problem? If it's no problem, I won't send it to check. After a moment, the master said that it's OK to wait for the next inspection. I said that I sent it for inspection. Why did I issue a repair order last night. He said it was the same. Then a few minutes later, I called 400 again. The customer service said that the inspection order and the repair order were different. The repair order was just broken and needed to be repaired. I said that it was not clear that it made me delay the time? The customer service said that it would not be changed for 15 days. Ah, Suning, a big swindler, is just trying to trick people, cheat consumers on their money and time, and play tricks. In the future, Suning won't charge for things,
