Conceal or Randomize Communications
LOW MODERATE HIGHRequirements NIST SOURCE
Implement cryptographic mechanisms to conceal or randomize communication patterns unless otherwise protected by [alternative physical controls].
Discussion (NIST Supplemental Guidance)
Concealing or randomizing communication patterns addresses protection from unauthorized disclosure of information. Communication patterns include frequency, periods, predictability, and amount. Changes to communications patterns can reveal information with intelligence value, especially when combined with other available information related to the mission and business functions of the organization. Concealing or randomizing communications prevents the derivation of intelligence based on communications patterns and applies to both internal and external networks or links that may be visible to individuals who are not authorized users. Encrypting the links and transmitting in continuous, fixed, or random patterns prevents the derivation of intelligence from the system communications patterns. Alternative physical controls include protected distribution systems.
Implementation Guidance
Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.
No engineering interpretation has been authored for SC-8(4) yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.
Assessment
Assessment Objectives
- alternative physical controls to protect against unauthorized disclosure of communication patterns are defined;
- cryptographic mechanisms are implemented to conceal or randomize communication patterns unless otherwise protected by <SC-08(04)_ODP alternative physical controls>.
Examine
[SELECT FROM: System and communications protection policy; procedures addressing transmission confidentiality and integrity; system design documentation; system configuration settings and associated documentation; system audit records; system security plan; other relevant documents or records].
Interview
[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities; system developer].
Test
[SELECT FROM: Cryptographic mechanisms supporting and/or implementing concealment or randomization of communication patterns; mechanisms supporting and/or implementing alternative physical safeguards; organizational processes for defining and implementing alternative physical safeguards].
Overlays
STIGs & CCIs
No STIG checks or CCI mappings are currently loaded for SC-8(4). This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.
Learn more about STIG/CCI integration →Evidence
Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.
Policy
- System and communications protection policy
- system security plan
Configuration
- system design documentation
- system configuration settings and associated documentation
Testing
- Cryptographic mechanisms supporting and/or implementing concealment or randomization of communication patterns
- mechanisms supporting and/or implementing alternative physical safeguards
- organizational processes for defining and implementing alternative physical safeguards
Other Records
- procedures addressing transmission confidentiality and integrity
- system audit records
- other relevant documents or records