Reverse engineering is the process of studying a device, program, or firmware to understand how it works when the original design documents are missing or incomplete. Analysts inspect hardware behavior, code, file formats, and interfaces to reconstruct structure and function. In legacy embedded devices, this can reveal how inputs are mapped, how cartridges or modules are checked, and how different model variants are separated.
In cyber security, reverse engineering is a core defensive skill. It helps researchers analyze malware, confirm what a binary does, recover undocumented protocols, and find flaws before attackers do. It is also useful for preservation and emulation, where old software must be made to run without the original platform. Because the process exposes hidden assumptions and implementation details, it can support patching, compatibility work, and security review of products that are no longer fully documented.