A cryptocurrency is a digital currency that uses a blockchain and relies on cryptography for security.
The nature of the blockchain means that individuals can transact directly with each other, even if they don’t trust each other. Cryptocurrencies don’t need a centralized party like a bank to carry out transactions between individuals.
Cryptography is used to keep transactions secure and to control the creation of additional units of a currency.
Bitcoin is considered the first cryptocurrency and is currently, the largest and most famous, out of the more than 1,300 cryptocurrencies now available on the interwebz.