What is Blockchain?

Blockchain is a distributed ledger consisting of a chain of financial transactions in which each subsequent unit is connected with previous ones via cryptography methods.

Essentialy, blockchain is a database (log) of all transactions and a constantly growing list of log records called blocks that are linked together and protected by cryptography. Each block usually contains a hash pointer, as a link to the previous block, a timestamp, and transaction data. This makes blockchains protected from any data alterations. In order to be used as a distributed register, blockchain is usually managed by a p2p network that collectively stick to validation protocols.