Cryptocurrency is a digital form of currency.
Cryptocurrencies work using a technology called Blockchain, that stores the currency ledger on a decentralised network of computers. The network records the transactions and the value of the currency. This network can not be corrupted, as it is stored on every node of the blockchain that is being used.
As at the end of February, 2018, there were 1527 cryptocurrencies being traded, with a combined market cap of $441 Billion dollars.
Cryptocurrencies are growing in popularity every day, especially amongst millennials.