The use of physical measures (such as locks and tamper-proofing) or policies (such as Clean Desk) in order to protect sensitive information from unauthorized access.
In concept, Physical Security covers everything from paper shredders to bullet-proof glass. Since this site is focused on information security, we are mostly interested in physical means of protecting sensitive information.
On-topic questions include the technology or policies around:
- Safe disposal of documents and devices.
- Physical access to secure areas, including locks, fingerprint / iris scans, key-cards, etc.
- Secure cabinets for sensitive or critical servers.
- Tamper-proof or tamper-evident device casings.
- Physical means to prevent side-channel attacks on computer hardware; cold boots, power analysis, access to diagnostic ports, etc.
- Policies for incident response.
- and more.
Things that are sometimes on-topic, depending on the focus of the question, include:
- Closed-circuit camera systems.
- Alarm systems.