Smart contracts are self-executing programs stored on a blockchain. They enforce predefined rules, move assets, and update state automatically when conditions are met. Because the code runs on a distributed ledger, its behavior is transparent and hard to alter, which makes it useful for governance, payments, voting, and machine-to-machine coordination.
In cyber security, smart contracts matter because they turn policy into executable control. That can strengthen defenses by enforcing access control, treasury limits, or workflow approvals without relying on a single administrator. But it also creates risk: bugs in the contract, bad oracle inputs, weak permissions, or unsafe upgrade paths can be exploited, and the contract will often execute exactly as written. Common protections include code audits, formal verification, least-privilege design, multisignature controls, and careful handling of external data.