Smart Contract Security and Auditing Cheat Sheet

Smart contract security is the discipline of finding and closing the gap between what a contract's code actually does and what its authors believe it does, since deployed Solidity code is public, immutable, and directly controls real money with no customer-support line to call after a mistake. It matters because a single missed check can drain a protocol in one transaction, and OWASP's own incident data shows losses concentrated in a handful of recurring patterns rather than exotic one-off bugs. The mental model worth keeping throughout: most catastrophic exploits are not clever cryptographic breaks but ordinary logic errors amplified by composability and atomicity — a flash loan, a reentrant call, or a manipulated price feed simply lets an attacker execute that ordinary mistake at unlimited scale inside a single block, so auditing is as much about tracing money and control flow across a whole system as it is about spotting individual unsafe lines.