The core technology of blockchain was proposed as early as 1991. At that time, it was only used to mark electronic documents and record every change to judge whether the documents had been tampered with. Until 2009, a Japanese-American named Satoshi Nakamoto ( In an article about the conception of virtual currency (whose true identity is doubtful), the application of the blockchain was first proposed (creating Bitcoin), and the blockchain began to receive widespread attention. RS232/RS485 serial port communication What is blockchain?Blockchain is a new type of data storage structure with the characteristics of decentralization, non-tampering, traceability, traceability, collective maintenance, and openness and transparency. Blockchain involves knowledge in many fields such as mathematics, encryption algorithms, cryptography, the Internet, and computer programming.Features of blockchainDecentralization: The most important feature of the blockchain is decentralization. What is centralization? That is, around a fixed center.Take transfer as an example, then there is a ledger to store the information of all people. If A transfers 100 yuan to B, then A’s deposit data on the ledger will be -100, and B’s data will be +100. This is centralization, and all transactions around this ledger. If one day a malicious bank employee tampers with the ledger data, it will cause serious consequences at this time, so there is a huge risk of centralization. In order to prevent data from being easily tampered with, we need more ledgers to store transaction information at the same time, so that only more than half of the bills can be modified at the same time to complete the modification goal, which greatly increases the difficulty of data tampering, which is also called distribution. style bill.Asymmetric information encryption: The blockchain adopts the encryption method of the hash algorithm. Whether it is a sentence, a book, or larger data, the hash algorithm can convert it into a 256-bit binary string, and the difficulty is reversed. It is extremely large, and can only rely on the continuous use of different information for comparison. Taking a computer that can perform 10,000 comparisons per second as an example, it takes years to crack.The blockchain can be understood as composed of blocks and chains, and the blockchain is composed of countless blocks and chains. A block can be understood as SPI communication protocol a bill for each record transaction, so how to connect them?Each block stores the encrypted information of the previous block, and also stores the data and encrypted information of this time, so that all blocks are linked.