Cryptocurrencies are digital or virtual currencies that use cryptography for security. They are decentralized, meaning they operate independently of a central bank or government authority. Cryptocurrencies can be used to purchase goods and services online, and can also be exchanged for other forms of currency. As an investment asset, cryptocurrencies have become increasingly popular due to their potential for high returns on investment. Investors should understand the risks associated with investing in cryptocurrencies before making any decisions.