Ionizing radiation is energy, such as X-rays, gamma rays, or particle radiation, that is strong enough to knock electrons out of atoms. That process can damage living tissue, but it can also disturb electronic components by creating charge inside semiconductors and memory cells.
In cyber security, this matters anywhere hardware must stay reliable under hostile or unusual conditions: medical devices, industrial controllers, satellites, and secure labs. Attackers and researchers can use ionizing radiation as a fault-injection method to trigger bit flips, crashes, or authentication errors in chips. Defenses include shielding, access control around radiation sources, error-correcting code, watchdogs, and redundant checks so a single radiation event does not turn into a security failure.