How Smart Contracts Work — and Common Security Risks
Small programs that live on a blockchain and enforce rules automatically.
A smart contract is a program deployed to a blockchain. Once deployed, anyone can call its functions by sending a transaction. The contract's rules are enforced by the network — no operator can override them and no user can bypass them.
Because contracts hold funds and cannot easily be changed after deployment, bugs are expensive. Common issues include reentrancy, where a contract can be called back into before it finishes updating its state, and access-control mistakes, where a function meant to be restricted is left open.
Most established projects publish audits from independent security firms. An audit is not a guarantee — it is one professional review of a codebase at a point in time. Bug bounties, formal verification, and gradual roll-outs all add additional layers of assurance.
For users, the safest baseline is to treat every contract interaction as if it could fail. Review approvals, revoke ones you no longer need, and be skeptical of any interface that asks you to sign something you don't understand.