AC.L2-3.1.19 · Level 2

Encrypt CUI on mobile devices and mobile computing platforms.

NIST SP 800-171 Rev 2 · §3.1.19

Assessment objectives

From NIST SP 800-171A · 2 objectives must be met to satisfy this control

3.1.19[a] mobile devices and mobile computing platforms that process, store, or transmit CUI are identified.

Examine

[SELECT FROM: Access control policy; procedures addressing access control for mobile devices; system design documentation; system configuration settings and associated documentation; encryption mechanisms and associated configuration documentation; security plan; system audit logs and records; other relevant documents or records].

Interview

[SELECT FROM: Personnel with access control responsibilities for mobile devices; system or network administrators; personnel with information security responsibilities].

Test

[SELECT FROM: Encryption mechanisms protecting confidentiality of information on mobile devices].

3.1.19[b] encryption is employed to protect CUI on identified mobile devices and mobile computing platforms.

What we look for in practice

The following are placeholder notes that should be refined based on practice experience.

What assessors look for in practice. Documented evidence that this control is implemented across all CUI-handling systems within scope. Specific artifacts vary, but expect requests for written procedures, system configurations, and operational records demonstrating the control is active.

Common failure patterns. Typical issues include incomplete documentation, inconsistent implementation across systems, and missing periodic review records. Refine this section as your practice accumulates direct assessment experience.

Strong evidence looks like. Formal policy referencing this control, technical configurations demonstrating enforcement, periodic review logs with sign-off, and procedures for handling exceptions.

Scoring and POA&M context. 3-point control under the DoD Assessment Methodology. Meaningful but more contained scoring impact. Not POA&M-eligible — must be implemented at assessment time.