The technology that powers digital currencies like Bitcoin is blockchain. Blockchain is a decentralized and distributed ledger technology that records transactions across many computers, ensuring transparency and security. Each transaction is grouped into a block and, once validated, added to a chain of existing blocks, forming an immutable record. This design enhances security against fraud and hacking, as altering any information would require consensus across the network. Blockchain technology not only supports cryptocurrencies but also has potential applications in various sectors, including supply chain management and healthcare.