A radio clock synchronizes its time from an external broadcast signal rather than relying only on an internal oscillator. It listens for a time reference such as a long-wave or short-wave transmission and uses that signal to correct drift. This makes it useful in embedded devices, appliances, and any system that needs accurate time with low power and minimal local hardware.
In cybersecurity, time is a security dependency. Logs, certificates, access tokens, scheduled jobs, and replay protections all rely on correct timestamps. If a radio clock receives weak, jammed, or false time data, a device may quietly drift or accept the wrong time, which can break audits or weaken controls. Defenders reduce this risk by validating time against multiple sources, watching for sudden jumps, and treating external time as input that can be lost, delayed, or manipulated.