Blockchain technology is a decentralized digital ledger that securely records transactions across a network of computers. Each transaction is grouped into a block, cryptographically linked to the previous one, forming a tamper-resistant chain. This ensures transparency, security, and immutability, as altering any data would require changing all subsequent blocks. Blockchain eliminates the need for intermediaries, enabling peer-to-peer transactions in applications like cryptocurrencies (e.g., Bitcoin, Ethereum), smart contracts, and supply chain tracking. Its distributed nature prevents single points of failure, reducing fraud risks. Businesses leverage blockchain for secure data sharing, digital identity verification, and asset tokenization. Despite challenges like scalability and energy consumption, its potential to revolutionize finance, healthcare, and governance makes blockchain a transformative innovation in the digital era.