Cryptocurrency, often referred to as crypto, is a type of digital or virtual currency that uses cryptography for security. Unlike traditional currencies issued by governments (like the US dollar or the euro), cryptocurrencies are decentralized and typically operate on a technology called blockchain, which is a distributed ledger that records all transactions across a network of computers.

Some popular cryptocurrencies include Bitcoin (BTC), Ethereum (ETH), and Ripple (XRP). These digital currencies can be used for various purposes, including online purchases, investment, and as a store of value. Cryptocurrencies have gained significant attention and popularity due to their potential for financial innovation and the underlying technology's ability to provide secure, transparent, and decentralized systems. However, they are also subject to regulatory and market volatility.