Cryptocurrency is a digital or virtual form of currency that uses cryptography for security. Unlike traditional currencies issued by governments (such as the US dollar or euro), cryptocurrencies operate on decentralized technology called blockchain. Bitcoin was the first cryptocurrency, created in 2009, and since then, thousands of other cryptocurrencies have been developed, including Ethereum, Ripple, and Litecoin.

People can buy, sell, and trade cryptocurrencies on various online platforms called cryptocurrency exchanges. Cryptocurrencies have gained popularity as speculative investments and as a means of transferring value across borders quickly and with lower fees compared to traditional financial systems. However, it's essential to be aware of the high volatility and risks associated with cryptocurrencies and to understand the technology and market dynamics before investing.