Interface discovery is the process of figuring out how two components communicate so they can work together correctly. That usually means identifying signal levels, message formats, timing, pin functions, command sets, or protocol rules when documentation is missing, incomplete, or untrusted.
In cyber security, interface discovery matters because opaque interfaces create risk. Defenders use it to safely integrate legacy devices, validate firmware behavior, and test whether a component really does what its vendor claims. Attackers use the same technique during reverse engineering to understand hidden protocols, locate debug ports, or build custom tools that interact with embedded systems. When a device depends on undocumented signaling, interface discovery is the step that turns an unknown part into something analyzable. It reduces guesswork, exposes assumptions, and helps separate normal engineering problems from security weaknesses such as weak authentication, unsafe control channels, or brittle trust boundaries.