IEC 62443-3-3 Foundational Requirements | Automation Engineering Body of Knowledge

ISA/IEC 62443-3-3 organises control-system security requirements under seven Foundational Requirements (FRs). Each FR is a security objective — and a home for a set of system requirements (SRs) and requirement enhancements (REs) used when claiming Security Level capability for that objective.

This page is the overview (same pattern as the Security Program → SPE pages). Detailed SR summaries live on dedicated FR pages; the packing list that maps SRs/REs to SL 1–4 is Annex B; vector notation and the worked radar example are on the FR / SL Vector page.

Teaching note: Content paraphrases Part 3-3 for learning. Always refer to the published standard for normative SR/RE wording.

The seven Foundational Requirements

FR	Name	Detail
FR 1	Identification and Authentication Control (IAC)	FR 1 page
FR 2	Use Control (UC)	FR 2 page
FR 3	System Integrity (SI)	FR 3 page
FR 4	Data Confidentiality (DC)	FR 4 page
FR 5	Restricted Data Flow (RDF)	FR 5 page
FR 6	Timely Response to Events (TRE)	FR 6 page
FR 7	Resource Availability (RA)	FR 7 page

FR pages: FR 1 | FR 2 | FR 3 | FR 4 | FR 5 | FR 6 | FR 7

What each FR is for

FR 1 IAC — Identify and authenticate users (humans, processes, devices) before access.
FR 2 UC — Enforce what authenticated users may do (authorisation / least privilege).
FR 3 SI — Protect integrity of system data, software and communications.
FR 4 DC — Protect confidentiality / resist eavesdropping on selected channels.
FR 5 RDF — Segment and restrict where information may flow.
FR 6 TRE — Detect, notify, preserve evidence and respond in time.
FR 7 RA — Keep essential resources available under stress / DoS conditions.

Related Part 3-3 teaching pages

FR / SL Vector — seven-element notation, SL-T/C/A comparison, BPCS radar example.
Annex B – SR/RE mapping to SL 1–4 — which requirements pack each SL-C claim.
Security Levels (Annex A.3.2) — SL types and 0–4 scale (not duplicated on FR pages).

Key takeaways

Seven FRs structure Part 3-3 system requirements.
Each FR has its own SR set; REs raise capability for higher SLs.
Zone posture is usually a vector across FRs — not one blanket number.
Annex B is the SL packing list; Security Levels pages explain what the numbers mean.

IEC 62443-3-3 Foundational Requirements (FR1–FR7)

The seven Foundational Requirements

What each FR is for

Related Part 3-3 teaching pages

Key takeaways