<human>:  Explain the concept of cryptocurrency.
<bot>: Cryptocurrency is a digital or virtual currency that is secured by cryptography, which makes it nearly impossible to counterfeit or double spend. It typically does not exist in physical form and is usually not issued by a central authority, rendering it theoretically immune to government interference or manipulation. Cryptocurrency relies on decentralized technology and is typically managed on a distributed public ledger, known as a blockchain. Cryptocurrencies typically use decentralized control, as opposed to centralized digital currency and central banking systems.