NIST SP 800-53 Rev. 5 SC-12(6) — Physical Control Of Keys

What this control requires

Maintain physical control of cryptographic keys when stored information is encrypted by external service providers. This ensures that data stored by external providers, such as cloud services or data centers, remains protected from unauthorized disclosure or modification. This control supports the Cryptographic Key Storage and Management System capability within the System and Communications Protection family.

In plain English

Maintain physical control of cryptographic keys when stored information is encrypted by external service providers. In practice, this means you can prove you information management-level controls on a defined cadence.

Why it matters

SP 800-53 is the catalogue every U.S. federal authorisation (FedRAMP, FISMA, CMMC) and most regulated industries point at. A missing control surfaces as a Plan of Action & Milestones (POA&M) item that an Authorizing Official must approve before the Authority To Operate is granted or renewed.

This control is rated critical in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping.

What an auditor looks for

A 3PAO (FedRAMP) or Independent Assessor (NIST RMF) tests against NIST SP 800-53A assessment procedures. For each control they expect a documented implementation that addresses every assessment objective (Examine, Interview, Test) and an implementation summary in the System Security Plan.

Within System and Communications Protection, the assessor will trace your implementation back to the catalogue reference (Control SC-12(6)) and look for objective evidence on the latest two assessment cycles.

How to implement

Cloud Posture

CSPM. Run Wiz / Prisma / Defender for Cloud / Security Command Center over every account; auto-ticket findings above your accepted-risk threshold.

Physical Security

Inheritance. For cloud-only operations, inherit physical controls from the provider's SOC 2 / ISO 27001 report and document the inheritance in the SoA.

Operational checklist

• Information. Document the trigger, the owner and the cadence.
• Security. Document the trigger, the owner and the cadence.
• Data. Document the trigger, the owner and the cadence.
• Physical. Document the trigger, the owner and the cadence.
• Protection. Document the trigger, the owner and the cadence.
• Scope: management, information, cryptographic keys, system, service, protection, external service providers, services.

Evidence to collect

• Vendor Risk Management. vendor_risk_management evidence
• Infra Scan. Continuous infrastructure-posture telemetry — AWS Config, Azure Policy compliance, GCP Organisation Policy, Wiz / Prisma findings.

Third-party risk management evidence (assessments, contracts, due diligence) shows supplier oversight. Focus: Physical Control Of Keys.

Common pitfalls

• Treating CSPM findings as a backlog instead of a hot queue: findings older than the policy SLA accumulate until the auditor asks why.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• NIST SP 800-171 Rev. 3 3.16.3 — External System Services
• BSI C5:2020 SSO-03 — Directory of service providers and suppliers

Related controls in NIST SP 800-53 Rev. 5

• Control SC-7(19) — Block Communication From Non-Organizationally Configured Hosts
• Control SA-5(2) — Security-Relevant External System Interfaces
• Control SA-9(2) — Identification Of Functions, Ports, Protocols, And Services
• Control SA-9 — External System Services
• Control SA-9(3) — Establish And Maintain Trust Relationship With Providers
• Control SA-9(4) — Consistent Interests Of Consumers And Providers

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control SC-12(6)

Topics: data protectionvendor riskvendor managementsupply chain securitycloud posturephysical security