What is a blockchain?
A blockchain is a type of database where data is stored in linked blocks. Each block contains a batch of transactions and a cryptographic reference to the previous block. This chain structure makes it computationally infeasible to alter historical records without redoing all subsequent blocks.
Key properties
- Decentralised — thousands of nodes hold copies of the same data
- Transparent — all transactions are publicly visible
- Immutable — confirmed transactions cannot be reversed
- Permissionless — anyone with a wallet can participate
Public vs private blockchains
Public blockchains like Ethereum and BNB Smart Chain are open to anyone. Private blockchains are controlled by a single organisation and offer fewer trust guarantees.
Why blockchains enable DeFi
Because blockchains are trustless — you don't need to trust a company, you trust the math — they're the perfect foundation for financial protocols. Smart contracts on blockchains execute automatically, hold funds securely, and settle transactions in seconds.