Cryptocurrency is a digital or virtual currency that uses cryptography for security. It is not regulated by any central bank or government and operates independently of a centralized system. Fiat currency, on the other hand, is a nationally recognized currency that is issued and regulated by a government or central bank. Fiat currency is backed by physical assets, whereas cryptocurrency is not. Additionally, cryptocurrency is decentralized, meaning that it is not controlled by any one entity, while fiat currency is controlled by governments and/or banks. Furthermore, cryptocurrency transactions are anonymous and secure, while fiat currencies are more vulnerable to counterfeiting due to the lack of cryptographic security. Finally, cryptocurrency transactions are almost instantaneous and completely global, while fiat currency transactions may be limited by location and speed.