An input device is hardware that sends commands or data to a system. Common examples include keyboards, mice, touchscreens, game controllers, and specialized sensors. The device translates a physical action into signals the operating system or application can interpret.
In cyber security, input devices matter because they sit on a trusted path into a computer or embedded system. Attackers can abuse that trust with malicious USB devices that masquerade as keyboards, inject commands, or trigger unwanted actions. Defenders protect against this by restricting device permissions, using port controls, monitoring new peripherals, and hardening firmware and driver handling. In everyday hardware mods, changing an input device may be harmless, but it can also add new interfaces that expand the attack surface.