Blockchain is a distributed database technology, which is a continuous chain of blocks containing both its own information and a link to the previous block of the chain. At the same time, the chain does not have a single server, the entire blockchain is stored on the computers of blockchain users and is completely duplicated. Each user sees the entire blockchain as a whole.
Blockchain is based on asymmetric encryption: the addresses of the blockchain users are public keys and their derivatives. Transactions between blockchain addresses are signed with private keys. Blockchain blocks are collections of user transaction records and other additional information. Various technologies are used to form new blocks.