Formal verification is a method of proving, with mathematics, that a system or result satisfies precise rules or properties. Instead of testing a few examples, engineers define what must always be true and use logical proofs or automated checkers to confirm it. This can cover code, hardware, protocols, or even AI-assisted reasoning steps.
It matters in cyber security because many failures are not obvious in normal testing. Formal verification can help prove the absence of certain memory bugs, race conditions, privilege-escalation paths, or protocol flaws before deployment. It is especially valuable for kernels, cryptographic implementations, sandboxing layers, and high-trust systems where a single mistake can become an exploit. In defense, it strengthens assurance; in offense, attackers often target the parts of a system that were not formally checked or where assumptions were incomplete.