A human-computer interface is the point where a person interacts with a digital system through screens, buttons, voice, touch, gestures, or wearable controls. It is not just the visible front end: it includes the prompts, feedback, and actions that let users operate software and hardware.
In cyber security, the interface is a major attack surface because people are often the weakest link. Phishing pages, fake login screens, misleading permission dialogs, and malicious app prompts all abuse the interface to trick users into revealing credentials or approving unsafe actions. Defenders reduce that risk by designing clear warnings, strong authentication flows, least-privilege approval steps, and interfaces that make suspicious behavior easy to spot. In wearable tech, the interface matters even more because small displays and limited input options can make trust and usability harder to balance.