13 Jul 2026CMMC Phase II suspended: no C3PAO assessments can be designated. DFARS 7012 and Rev 2 still apply.What changed, and what did not

NIST SP 800-171 Rev 2 · 3.13 System & Communications Protection

3.13.16 Encrypt CUI at rest

Protect the confidentiality of CUI at rest.
SPRS weight
1
1 point deducted from 110 when not implemented.
CMMC level
L2
Level 2 only; not among the 17 Level 1 practices.
Assessment objectives
1
From NIST SP 800-171A, each one a “determine if” an assessor answers.

What an assessor checks

NIST SP 800-171A breaks 3.13.16 into 1 objectives. Every one has to be met for the requirement to be met; a partial answer scores as not implemented.

  1. Determine if the confidentiality of CUI at rest is protected.
Examine
[SELECT FROM: System and communications protection policy; procedures addressing protection of information at rest; security plan; system design documentation; list of information at rest requiring confidentiality protections; system configuration settings and associated documentation; cryptographic mechanisms and associated configuration documentation; other relevant documents or records].
Interview
[SELECT FROM: System or network administrators; personnel with information security responsibilities; system developer].
Test
[SELECT FROM: Mechanisms supporting or implementing confidentiality protections for information at rest].

If it is open: POA&M eligibility

May be carried on a Level 2 POA&M · 1 point deducted

A 1-point requirement outside the six named exclusions - eligible to carry, and NOT MET until a closeout assessment confirms it.

A POA&M is only permitted at a score of 88 or above, and closes in one 180-day window. Check a full gap list or compute your score.

Where 3.13.16 maps

NIST SP 800-53 Rev 5

  • SC-13 Cryptographic Protection
  • SC-28 Protection of Information at Rest

NIST CSF 2.0

  • Data-at-rest is protected Data Security

SOC 2

No direct mapping.

Query it from your own tools

This page and the MacTech CMMC MCP server render the same dataset. Ask your assistant and it will answer from the methodology, not from memory.

lookup_control 3.13.16
get_assessment_objectives 3.13.16
generate_poam_entries ["3.13.16"]

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Working notes on System & Communications Protection

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