A friction layer is a deliberate design step that slows down a risky action so it is less likely to happen automatically. In security, it is used to interrupt habit-driven behavior and force a user to notice what they are about to do, such as opening an external file, approving a login, or scanning a code. The goal is not always to block the action, but to make it feel consequential enough that the user pauses and checks the risk.
Friction layers matter because many attacks depend on speed, trust, and routine. A phishing message that looks normal can succeed if the victim clicks before thinking. In collaboration tools, hiding or obscuring a QR code from external senders is a good example: the user must take an extra step before scanning, which can reduce casual exposure to a malicious destination. Friction helps defense by breaking autopilot, but it does not replace filtering, identity checks, or downstream protection after the interaction.