Persistent identity is a stable digital reference that keeps pointing to the same object, user, device, or record over time, even as its attributes change. In cyber security, it is used to track assets across systems, sessions, and lifecycle stages without confusing one thing for another. Examples include device IDs, asset records, product passports, and long-lived account identifiers.
It matters because security controls depend on knowing what is being authenticated, authorized, logged, and audited. If identity is unstable or duplicated, attackers can exploit the confusion by spoofing records, hijacking updates, or creating inconsistent copies of the same asset. Defenders use persistent identity to support traceability, integrity checks, revocation, and forensic correlation, but they must protect it with strong authentication, validation rules, and careful change control.