---
title: "NIST 800-171 3.1.19 (AC.L2-3.1.19): Encrypt CUI on Mobile"
description: "NIST SP 800-171 3.1.19 Encrypt CUI on Mobile: 3 SPRS points, not allowed on a CMMC POA&M. The text, what assessors check and the evidence."
url: https://policycortex.com/nist-800-171/access-control/3.1.19
sealed: 2026-11-11
amended: 2026-11-11
register: nist-800-171/access-control/3.1.19
records: 7
digest: sha3:8118af4934d03181ab34f2a19903582828a031de6a1d3c54abca6999f04550a6
---

# NIST 800-171 3.1.19 (AC.L2-3.1.19): Encrypt CUI on Mobile

NIST 800-171 / Access Control / 3.1.19

"Encrypt CUI on mobile devices and mobile computing platforms." ([NIST SP 800-171 Rev. 2, requirement 3.1.19](https://doi.org/10.6028/NIST.SP.800-171r2))

CMMC Level 2 practice AC.L2-3.1.19.

## What 3.1.19 means in practice

Any phone, tablet or laptop that carries CUI encrypts it, either the whole device or a managed container that holds the CUI. Device management requires the encryption and reports any device that lacks it.

## SPRS points and the CMMC POA&M

- **CMMC Level 2 practice**: AC.L2-3.1.19
- **SPRS points**: 3 points. When it is not met, the DoD Assessment Methodology subtracts 3 from the score of 110.
- **CMMC POA&M**: Not allowed. It is worth 3 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.

Sources: [NIST SP 800-171 DoD Assessment Methodology, version 1.2.1 (June 24, 2020), Annex A](https://www.acq.osd.mil/asda/dpc/cp/cyber/docs/safeguarding/NIST-SP-800-171-Assessment-Methodology-Version-1.2.1-6.24.2020.pdf); [32 CFR 170.21, Plan of Action and Milestones requirements](https://www.ecfr.gov/current/title-32/section-170.21).

## What an assessor checks for 3.1.19

NIST SP 800-171A gives 2 determination statements for 3.1.19, each found satisfied or other than satisfied. Determine if:

- 3.1.19[a] mobile devices and mobile computing platforms that process, store, or transmit CUI are identified.
- 3.1.19[b] encryption is employed to protect CUI on identified mobile devices and mobile computing platforms.

[NIST SP 800-171A (June 2018), assessment objectives for 3.1.19](https://doi.org/10.6028/NIST.SP.800-171A)

## Evidence that shows 3.1.19 is met

- Device management compliance rules that require storage encryption.
- An encryption status report for the mobile devices and laptops that hold CUI.
- Container or app protection settings, where container encryption is used instead.

## How PolicyCortex gathers the evidence

PolicyCortex reads this evidence with the collectors below, read only, and grades 3.1.19 from it. Each line says what the product checks.

- **Microsoft Intune: Compliance policies · Device configurations.** Checks that every mobile device and laptop Intune manages is required to encrypt its storage.

## Related pages

- **Calculator**: [SPRS score calculator: mark 3.1.19 and the other 109 requirements and see the score.](https://policycortex.com/sprs-score-calculator#family-AC)
- **Sample package**: [Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.](https://policycortex.com/sample-package)
- **Family**: [All 22 Access Control requirements (3.1).](https://policycortex.com/nist-800-171/access-control)
- **Previous**: [3.1.18: Mobile Device Connection](https://policycortex.com/nist-800-171/access-control/3.1.18)
- **Next**: [3.1.20: External Connections](https://policycortex.com/nist-800-171/access-control/3.1.20)
- **All requirements**: [All 110 NIST SP 800-171 requirements, by family.](https://policycortex.com/nist-800-171)

Meet the requirement once. Keep the evidence current. [Request Access](https://app.policycortex.com/auth?mode=request-access) · [Book a call](https://policycortex.com/book)

## Register colophon

| Seq | Label | SHA3-256 | Prev |
|---|---|---|---|
| REC 0000 | REQUIREMENT | db1888137419 | a7bfff9d4a38 |
| REC 0001 | MEANING | 0c0d777f381b | db1888137419 |
| REC 0002 | POINTS AND POA&M | ca0592d90598 | 0c0d777f381b |
| REC 0003 | ASSESSMENT OBJECTIVES | b839277f59f7 | ca0592d90598 |
| REC 0004 | EVIDENCE | 4cccc2ae4360 | b839277f59f7 |
| REC 0005 | COLLECTORS | 3eebb6042c76 | 4cccc2ae4360 |
| REC 0006 | RELATED | 8118af4934d0 | 3eebb6042c76 |

Head sha3:8118af4934d03181ab34f2a19903582828a031de6a1d3c54abca6999f04550a6. Each digest is SHA3-256 over the previous digest, the register key, the record label, and the record copy; a second party can recompute it from this document.