Cryptocurrency is a digital or virtual form of currency that uses cryptography for security. It operates on a technology called blockchain, which is a decentralized and distributed ledger. Bitcoin was the first cryptocurrency, created in 2009, and since then, thousands of other cryptocurrencies have emerged, including Ethereum, Ripple, and Litecoin. People use cryptocurrencies for various purposes, including as a store of value, a means of exchange, and for investment. However, they are also known for their volatility and regulatory challenges.