Blockchain technology is a digital ledger system that records transactions in a secure, transparent, and decentralized way. Each transaction is grouped into a “block” and linked to previous blocks, forming a chain that cannot be easily altered. In cryptocurrency, blockchain ensures that all transactions are verified, permanent, and transparent without the need for banks or central authorities. It prevents fraud, double-spending, and manipulation, while allowing users to transfer value directly. Blockchain also enables smart contracts and decentralized applications, making it the backbone of cryptocurrencies and their secure operation worldwide.