A cryptocurrency (or “crypto”) is a digital asset that can circulate without the need for a central monetary authority such as a government or bank. Instead, cryptocurrencies are created using cryptographic techniques that enable people to buy, sell or trade them securely.
Bitcoin and most other cryptocurrencies are supported by a technology known as blockchain, which maintains a tamper-resistant record of transactions and keeps track of who owns what. The creation of blockchains addressed a problem faced by previous efforts to create purely digital currencies: preventing people from making copies of their holdings and attempting to spend them twice.