What is a blockchain

A blockchain allows two parties to transact with each other without an intermediary.

Usually, transactions are handled by a trusted third party, like a bank.

Now, imagine a network that allows peer-to-peer transactions which involves only two parties: the sender and the receiver.

That's what a blockchain does. It is a decentralized, distributed and transparent digital ledger which records transactions.

It's a database containing the history of all exchanges realized between users since its creation.

It stores encrypted blocks of data, then chains them together chronologically.

Validators (~servers) keep their own copy of the ledger and make sure they always agree with the content of the ledger.