Cryptocurrency is a digital form of currency. Unlike traditional currencies issued by governments (fiat currencies), cryptocurrencies are decentralized and typically based on blockchain technology. A blockchain is a distributed ledger enforced by a network of computers (nodes), which ensures transparency and security. 

The first and most well-known cryptocurrency, Bitcoin, was introduced in 2009 by an anonymous person or group of people using the pseudonym Satoshi Nakamoto. Since then, thousands of alternative cryptocurrencies, often referred to as altcoins, have been created, including Ethereum, Ripple, and Litecoin. 

With 24/7 markets that operate across the globe, traders can capitalize on the price fluctuations of cryptocurrencies at any time. The introduction of cryptocurrency CFDs (Contracts for Difference) has further expanded access, allowing traders to speculate on the price movements of digital currencies without owning the underlying asset.