Blockchain (a "chain of blocks") is a decentralized database whose copies are distributed across many computers in a network. Information in a blockchain is grouped into blocks, and each new block contains a cryptographic hash of the previous one. As a result, the blocks become rigidly linked to one another: changing the data in one of them without disrupting the entire subsequent chain is practically impossible.
It is precisely this structure that provides the technology's key properties — transparency, security and resistance to tampering. Since there is no single central server and copies of the ledger are stored by many participants, it is extremely difficult to bring the system down or covertly alter records. Confirmation of new blocks is carried out by network participants according to predefined rules — the consensus algorithm.
Where blockchain is used
The technology initially became known as the foundation for cryptocurrencies, but the scope of its application is much broader. Blockchain is used for smart contracts, accounting and data storage systems, digital documents, logistics and many other tasks where the reliability of records and the absence of a single point of trust are important. This makes blockchain one of the fundamental technologies of the digital economy.
