SA-17(05) Conceptually Simple Design

Control

Require the developer of the system, system component, or system service to:

Design and structure the security-relevant hardware, software, and firmware to use a complete, conceptually simple protection mechanism with precisely defined semantics; and
Internally structure the security-relevant hardware, software, and firmware with specific regard for this mechanism.

Discussion

The principle of reduced complexity states that the system design is as simple and small as possible (see [SA-8(7)](#sa-8.7) ). A small and simple design is easier to understand and analyze and is also less prone to error (see [AC-25](#ac-25), [SA-8(13)](#sa-8.13) ). The principle of reduced complexity 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 and 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 important benefit of reduced complexity is that it is easier to understand whether the 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 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.

Assessment Objective

the developer of the system, system component, or system service is required to design and structure the security-relevant hardware, software, and firmware to use a complete, conceptually simple protection mechanism with precisely defined semantics;
the developer of the system, system component, or system service is required to internally structure the security-relevant hardware, software, and firmware with specific regard for this mechanism.

Assessment Method

Examine

System and services acquisition policy enterprise architecture policy procedures addressing developer security architecture and design specifications for the system solicitation documentation acquisition documentation service level agreements acquisition contracts for the system, system component, or system service system design documentation system security architecture documentation system configuration settings and associated documentation developer documentation describing the design and structure of security-relevant hardware, software, and firmware components system security plan other relevant documents or records

Interview

Organizational personnel with system and service acquisition responsibilities organizational personnel with information security responsibilities system developer organizational personnel with information security architecture and design responsibilities

1. Prezentare generală

Titlu	Standard

1.1 Referințe

1.2 Cerințe identificate

1.3 Reglementări asociate

2. Cerințe identificate

Cerințe
Sursă	Cerință

3. Reglementări asociate

Reglementări
Sursă	Reglementare

Tichete legate

Legături
Tip de legătură	Tichet
is blocked by	SA-17(05) Conceptually Simple Design – Assessment Procedure

NIST -
EN: Publications of the National Institute of Standards and Technology (NIST), U.S. Department of Commerce, https://www.nist.gov/, from their electronic versions (OSCAL; SP 800-63-4 from its HTML version, https://pages.nist.gov/800-63-4/). Works of NIST employees are not subject to copyright protection in the United States (17 U.S.C. § 105); the OSCAL content is dedicated to the public domain worldwide (CC0 1.0); outside the United States NIST grants the right to reprint its technical series publications in all formats (NIST copyright statement). Republished courtesy of the National Institute of Standards and Technology; each document names its citation. Divided into sections and converted into the GRCA format, the wording unchanged. Only the versions published by NIST are authoritative.

DE: Veröffentlichungen des National Institute of Standards and Technology (NIST), U.S. Department of Commerce, https://www.nist.gov/, aus ihren elektronischen Fassungen (OSCAL; SP 800-63-4 aus ihrer HTML-Fassung, https://pages.nist.gov/800-63-4/). Werke von NIST-Beschäftigten sind in den USA urheberrechtlich nicht geschützt (17 U.S.C. § 105); die OSCAL-Inhalte sind weltweit gemeinfrei gestellt (CC0 1.0); außerhalb der USA räumt das NIST das Recht ein, seine Technical-Series-Publikationen in allen Formaten neu zu veröffentlichen (Copyright-Hinweis des NIST). „Republished courtesy of the National Institute of Standards and Technology“; jedes Dokument nennt seine Zitierangabe. In Abschnitte aufgeteilt und in das GRCA-Format umgewandelt, der Wortlaut unverändert. Maßgeblich sind allein die vom NIST veröffentlichten Fassungen.