The inverse-square law is a physical rule saying that the strength of a field or signal falls in proportion to the square of the distance from its source. In practice, doubling the distance can reduce received power to about one quarter, although walls, reflections, antenna patterns, and other losses often change the exact result.
In cyber security, this matters wherever information travels through air or space: Wi-Fi, Bluetooth, radio monitoring, and electromagnetic leakage from devices. Attackers may use distance-based signal loss to estimate how close a target is, place intercept equipment, or judge whether a wireless exploit is feasible from outside a building. Defenders use the same physics when designing secure wireless coverage, setting transmit power, and reducing spillover that could help eavesdroppers. The key lesson is that range is not just a convenience issue; it directly affects exposure, detection, and the practical reach of many attacks.