User: Can you explain to me what a cryptocurrency is?
Assistant: A cryptocurrency is a digital or virtual currency that is secured by cryptography, which makes it nearly impossible to counterfeit or double-spend. Cryptocurrencies use decentralized control as opposed to centralized digital currency and central banking systems. The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain, that serves as a public financial transaction database. Bitcoin was the first widely used cryptocurrency, shortly afterwards followed by Ethereum. Many other cryptocurrencies have since been created and there are now thousands of different digital tokens.