---
title: "NIST 800-171 3.8.6 (MP.L2-3.8.6): Encrypt Media in Transit"
description: "NIST SP 800-171 3.8.6 Encrypt Media in Transit: 1 SPRS point, allowed on a CMMC POA&M. The text, what assessors check and the evidence."
url: https://policycortex.com/nist-800-171/media-protection/3.8.6
sealed: 2026-11-11
amended: 2026-11-11
register: nist-800-171/media-protection/3.8.6
records: 7
digest: sha3:6cb99893be115322f70587bcd35ee2f71c32c4fa618afa5febf1df04de458209
---

# NIST 800-171 3.8.6 (MP.L2-3.8.6): Encrypt Media in Transit

NIST 800-171 / Media Protection / 3.8.6

"Implement cryptographic mechanisms to protect the confidentiality of CUI stored on digital media during transport unless otherwise protected by alternative physical safeguards." ([NIST SP 800-171 Rev. 2, requirement 3.8.6](https://doi.org/10.6028/NIST.SP.800-171r2))

CMMC Level 2 practice MP.L2-3.8.6.

## What 3.8.6 means in practice

CUI on portable digital media, such as a USB drive or external disk carried between sites, is encrypted unless a physical safeguard, like a locked container under escort, protects it instead. Because the encryption protects CUI, it should be FIPS validated.

## SPRS points and the CMMC POA&M

- **CMMC Level 2 practice**: MP.L2-3.8.6
- **SPRS points**: 1 point. When it is not met, the DoD Assessment Methodology subtracts 1 from the score of 110.
- **CMMC POA&M**: Allowed. It is worth 1 point, and 32 CFR 170.21(a)(2)(ii) admits requirements worth 1 point. Conditional status also needs a score of at least 88, and the item must be closed within 180 days.

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 3.8.6

NIST SP 800-171A gives one determination statement for 3.8.6.

- Determine if the confidentiality of CUI stored on digital media is protected during transport using cryptographic mechanisms or alternative physical safeguards.

[NIST SP 800-171A (June 2018), assessment objectives for 3.8.6](https://doi.org/10.6028/NIST.SP.800-171A)

## Evidence that shows 3.8.6 is met

- Encryption settings for removable media, such as BitLocker To Go or hardware-encrypted drives.
- The list of approved encrypted devices.
- The documented physical safeguards, where encryption is not used.

## How PolicyCortex gathers the evidence

No PolicyCortex collector reads the evidence for 3.8.6. Your team provides the evidence listed above.

## Related pages

- **Calculator**: [SPRS score calculator: mark 3.8.6 and the other 109 requirements and see the score.](https://policycortex.com/sprs-score-calculator#family-MP)
- **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 9 Media Protection requirements (3.8).](https://policycortex.com/nist-800-171/media-protection)
- **Previous**: [3.8.5: Media Transport](https://policycortex.com/nist-800-171/media-protection/3.8.5)
- **Next**: [3.8.7: Removable Media](https://policycortex.com/nist-800-171/media-protection/3.8.7)
- **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 | 507d3a12301a | 82d17f507ff2 |
| REC 0001 | MEANING | cec6bd247b74 | 507d3a12301a |
| REC 0002 | POINTS AND POA&M | 23031df72c73 | cec6bd247b74 |
| REC 0003 | ASSESSMENT OBJECTIVES | 407bb98f347f | 23031df72c73 |
| REC 0004 | EVIDENCE | 5c7917887696 | 407bb98f347f |
| REC 0005 | COLLECTORS | c8565b4ccdba | 5c7917887696 |
| REC 0006 | RELATED | 6cb99893be11 | c8565b4ccdba |

Head sha3:6cb99893be115322f70587bcd35ee2f71c32c4fa618afa5febf1df04de458209. 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.