NIST 800-171 3.1.13 (AC.L2-3.1.13): Remote Access Encryption

Employ cryptographic mechanisms to protect the confidentiality of remote access sessions.

NIST SP 800-171 Rev. 2, requirement 3.1.13

CMMC Level 2 practice AC.L2-3.1.13Published 2026-11-11

What 3.1.13 means in practice

Remote sessions are encrypted so CUI cannot be read on its way across the internet. That covers VPNs, remote desktop gateways and management connections, and because the encryption protects CUI it should come from FIPS-validated cryptographic modules, as 3.13.11 requires.

SPRS points and the CMMC POA&M

CMMC Level 2 practice: AC.L2-3.1.13
SPRS points: 5 points. When it is not met, the DoD Assessment Methodology subtracts 5 from the score of 110.
CMMC POA&M: Not allowed. It is worth 5 points, and 32 CFR 170.21(a)(2)(ii) admits only requirements worth 1 point, with one exception: 3.13.11 when encryption is used but not FIPS validated.
Scoring note: If the system permits no remote access, mark Met: Annex A subtracts nothing.

Sources: NIST SP 800-171 DoD Assessment Methodology, version 1.2.1 (June 24, 2020), Annex A; 32 CFR 170.21, Plan of Action and Milestones requirements.

What an assessor checks for 3.1.13

NIST SP 800-171A gives 2 determination statements for 3.1.13, each found satisfied or other than satisfied. Determine if:

3.1.13[a] cryptographic mechanisms to protect the confidentiality of remote access sessions are identified.
3.1.13[b] cryptographic mechanisms to protect the confidentiality of remote access sessions are implemented.

NIST SP 800-171A (June 2018), assessment objectives for 3.1.13

Evidence that shows 3.1.13 is met

VPN and remote gateway configuration showing the protocols and ciphers in use.
FIPS 140 validation certificates for the cryptographic modules that protect remote sessions.
A list of every remote access path with the encryption each one uses.

How PolicyCortex gathers the evidence

PolicyCortex reads this evidence with the collectors below, read only, and grades 3.1.13 from it. Each line says what the product checks.

Azure: VPN gateways. Reads each Azure VPN gateway's IPsec policies and checks that remote access connections use FIPS-validated cryptographic mechanisms.

Related pages

Calculator: SPRS score calculator: mark 3.1.13 and the other 109 requirements and see the score.
Sample package: Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.
Family: All 22 Access Control requirements (3.1).
Previous: 3.1.12: Remote Access Control
Next: 3.1.14: Remote Access Routing
All requirements: All 110 NIST SP 800-171 requirements, by family.

Related records

Guides and articles describe the work. The evidence that work produces is described in three proof pages, the architecture page, and the two pages on authorization.

proof.state: Proof of State. What the environment was, as of a date someone else picks: point-in-time records, content hashed and chained.
proof.change: Proof of Change. Who or what altered the environment, under what authority, with before and after state hashes.
proof.agency: Proof of Agency. What a machine was permitted to do before it acted, what it did, and what would have stopped it.
architecture: Architecture. How the chain is built and where the evidence is stored in each delivery mode.
authorization: Continuous ATO. How an authorizing official's decision is recorded with its package, and how the authorized system is checked against it every hour.
baseline: NIST SP 800-53. The Low, Moderate and High baselines as evidence, with the SSP, SAR and POA&M generated from one record.