A cryptocurrency or cyber currency is a medium of exchange, usually decentralized, that uses blockchain technology and cryptography to ensure the validity of transactions and the creation of new units of the currency. The Bitcoin, the first decentralized cryptocurrency, was created in 2009 by a user who used the pseudonym Satoshi Nakamoto. Since then, many other cryptocurrencies have been created. More recently, there has been a phenomenon of an explosion of numerous tokens that have been created based on the Ethereum protocol, especially after the massive wave of Initial Coin Offerings (commonly referred to as ICO) that occurred in 2017.

Logos of various cryptocurrencies

Unlike centralized banking systems, a large part of cryptocurrencies use a decentralized control system based on blockchain technology, which is a type of distributed ledger operated on a peer-to-peer network of thousands of computers, where all have an equal copy of the entire transaction history, preventing a central entity from making changes to the record or the software unilaterally without being excluded from the network.