Reduced Complexity
LOW MODERATE HIGHRequirements NIST SOURCE
Implement the security design principle of reduced complexity in [systems or system components].
Discussion (NIST Supplemental Guidance)
The principle of reduced complexity states that the system design is as simple and small as possible. A small and simple design is more understandable, more analyzable, and less prone to error. The reduced complexity principle applies to any aspect of a system, but it has particular importance for security due to the various analyses performed to obtain evidence about the emergent security property of the system. For such analyses to be successful, a small and simple design is essential. Application of the principle of reduced complexity contributes to the ability of system developers to understand the correctness and completeness of system security functions. It also facilitates the identification of potential vulnerabilities. The corollary of reduced complexity states that the simplicity of the system is directly related to the number of vulnerabilities it will contain; that is, simpler systems contain fewer vulnerabilities. An benefit of reduced complexity is that it is easier to understand whether the intended security policy has been captured in the system design and that fewer vulnerabilities are likely to be introduced during engineering development. An additional benefit is that any such conclusion about correctness, completeness, and the existence of vulnerabilities can be reached with a higher degree of assurance in contrast to conclusions reached in situations where the system design is inherently more complex. Transitioning from older technologies to newer technologies (e.g., transitioning from IPv4 to IPv6) may require implementing the older and newer technologies simultaneously during the transition period. This may result in a temporary increase in system complexity during the transition.
Implementation Guidance
Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.
No engineering interpretation has been authored for SA-8(7) 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
- systems or system components that implement the security design principle of reduced complexity are defined;
- <SA-08(07)_ODP systems or system components> implement the security design principle of reduced complexity.
Examine
[SELECT FROM: System and services acquisition policy; procedures addressing the security design principle of reduced complexity used in the specification, design, development, implementation, and modification of the system; system design documentation; security and privacy requirements and specifications for the system; system security and privacy architecture; system security plan; other relevant documents or records].
Interview
[SELECT FROM: Organizational personnel with the responsibility for determining system security and privacy requirements; organizational personnel with system specification, design, development, implementation, and modification responsibilities; system developers; organizational personnel with information security responsibilities].
Test
[SELECT FROM: Organizational processes for applying the security design principle of reduced complexity in system specification, design, development, implementation, and modification; mechanisms supporting the application of the security design principle of reduced complexity in system specification, design, development, implementation, and modification].
Overlays
STIGs & CCIs
No STIG checks or CCI mappings are currently loaded for SA-8(7). 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 services acquisition policy
- system security plan
Configuration
- system design documentation
- system security and privacy architecture
Testing
- Organizational processes for applying the security design principle of reduced complexity in system specification, design, development, implementation, and modification
- mechanisms supporting the application of the security design principle of reduced complexity in system specification, design, development, implementation, and modification
Other Records
- procedures addressing the security design principle of reduced complexity used in the specification, design, development, implementation, and modification of the system
- security and privacy requirements and specifications for the system
- other relevant documents or records