A blockchain is a digital public ledger of transactions that is stored across multiple computers or nodes. It records information related to assets such as money, property, and contracts in a shared database that is not managed by any single entity. It is essentially a distributed database that can securely and verifiably store data, allowing users to transfer and validate information without relying on a third party. The data is securely stored, encrypted, and linked together through the use of cryptography, making it virtually tamper-proof. By using a distributed network, blockchains are highly resilient to cyberattacks and other forms of tampering.