NIST SP 800-53 Rev. 5 SC-28(1) — Cryptographic Protection

What this control requires

Implement cryptographic mechanisms to prevent unauthorized disclosure and modification of information at rest on defined system components or media. The selected cryptographic methods should protect the confidentiality and integrity of organizational information, with strength corresponding to the data's security category or classification. This control supports the Cryptographic Protection Mechanism capability within the System and Communications Protection family.

In plain English

Implement cryptographic mechanisms to prevent unauthorized disclosure and modification of information at rest on defined system components or media. In practice, this means you can prove you policy 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-28(1)) and look for objective evidence on the latest two assessment cycles.

How to implement

Policy Management

Docs. Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA.

Operational checklist

• Policy. Document the trigger, the owner and the cadence.
• 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.
• Protection. Document the trigger, the owner and the cadence.
• Scope: management, information, system, protection, components, capability, media, system components.

Evidence to collect

• Policy Document. A signed and version-controlled policy / standard / procedure document.

Signed policy or standard documents the safeguard. Focus: Cryptographic Protection.

Common pitfalls

• Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced.

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 3.4.11 — Information Location
• HIPAA (45 CFR Part 164) 164.312(e)(2)(i) — Transmission Security - Integrity Controls

Related controls in NIST SP 800-53 Rev. 5

• Control MP-8 — Media Downgrading
• Control CP-9(8) — Cryptographic Protection
• Control SC-8(2) — Pre- And Post-Transmission Handling
• Control SC-34(2) — Integrity Protection And Read-Only Media
• Control SC-16(3) — Cryptographic Binding
• Control SC-16(1) — Integrity Verification

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control SC-28(1)

Topics: data protectionapi securitypolicy management