Take Bitcoin as an example, it has no physical form, but exists in a special account book. All bitcoin transactions are recorded in the ledger. Through the transaction records, we can calculate the number of bitcoins owned by each user. If a person owns bitcoin, it means that he can find the transaction records related to him in the ledger.
The ledger mentioned here is a software that we can download from Bitcoin official website. The underlying technology of this software is blockchain. In order to facilitate understanding, we usually say that blockchain is a general ledger.
The reason why the blockchain is used as the underlying technology of the ledger is to realize the decentralization of digital currency. It can be said that a series of problems encountered by digital currency and the solutions given all started from decentralization.
Second, the blockchain is a technology to ensure the safe use of digital currency. As we all know, blockchain technology has two characteristics: encryption and non-tampering, which can reduce the error probability of digital currency to zero. Because digital currency needs higher encryption, it must use blockchain technology to support it. At present, not only many industries in China are using blockchain technology, but also many foreign countries are actively using blockchain technology.
Blockchain is the underlying technology in digital currency, and Bitcoin is the first successful application of blockchain ... To understand this problem, we must first realize the fact that not all blockchains need to issue digital currency. At present, China strongly supports the "coin-free blockchain". Under normal circumstances, public blockchain needs to issue tokens as "rewards" to motivate users and maintain system operation, while ordinary blockchain, usually called alliance chain, can be issued or not.
1. public blockchain: a blockchain that anyone in the world can read and send transactions for validity confirmation, and anyone can participate in its * * * knowledge process. Bitcoin and Ethereum are typical applications of blockchain. The public blockchain is a fully distributed blockchain with open data, high user participation, easy network effect and easy application and promotion. This blockchain operation depends largely on the incentive mechanism, and tokens such as Bitcoin and Ethereum are used as incentive "rewards", so public chains need to issue tokens to maintain their own development and ecology.
2. Community blockchain: It means that the participating nodes are selected in advance in the blockchain. Nodes usually have good network connections and other cooperative relationships. The data on the blockchain can be open or internal. In a sense, partial distribution can be regarded as "partial decentralization". Each alliance in the chain has its own centralized management. For example, R3CEV of more than 40 banks is a typical alliance chain. This chain usually doesn't need much money.
3.privatechain: refers to the limited scope of node participation, such as strict authority management for users and data access and use of a specific organization ... The writing authority in a completely private chain is only in the hands of participants, and the reading authority can be open to the outside world or arbitrarily restricted. At present, it is mainly used for internal audit of companies. Therefore, the private chain does not need to issue currency, nor does it have the characteristics of decentralization. This is a centralized management mechanism.