IEC 81001-5-1 §5.3.3

IEC 81001-5-1: §5.3.3 SECURITY architectural design review

Architectural security decisions — the choice of trust boundaries, the design of authentication flows, the selection of encryption mechanisms, the partitioning of privilege levels — are difficult and expensive to reverse after implementation begins. A security architectural design review is the gate at which security expertise is applied to these decisions before they become embedded in code. Organizations that rely on penetration testing to identify architectural security weaknesses systematically incur two costs: the cost of implementing the wrong architecture in the first place, and the cost of redesigning or mitigating architectural problems discovered late. IEC 81001-5-1:2021 clause 5.3.3 requires a formal review of the security architectural design by personnel with appropriate security expertise, positioned before detailed design and implementation begin. The review must evaluate whether the architecture implements the defense-in-depth and secure design principles required by clauses 5.3.1 and 5.3.2, and whether it adequately addresses the threats identified in the threat model. The independence of the reviewer from the design team — or at minimum the requirement for demonstrated security expertise — prevents the review from being a formality performed by the designers on their own work.

IEC 81001-5-1:2021 is the first standalone cybersecurity standard purpose-built for health software and medical device software. Published in December 2021, it was adapted from IEC 62443-4-1 (industrial control systems security) to address the unique safety and regulatory context of medical devices — adding health-specific requirements that account for patient safety, clinical workflows, and the manufacturer-HDO relationship.

The standard mirrors IEC 62304's lifecycle structure but adds security-specific activities at every phase — planning, development, testing, release, and maintenance. It requires security risk management to be integrated with ISO 14971 safety risk management, not treated as a separate IT concern. FDA formally recognized it as Consensus Standard 13-122 on December 19, 2022 and references it as providing one acceptable framework for satisfying the cybersecurity requirements of Section 524B(b)(2), which requires manufacturers to design, develop, and maintain processes and procedures to provide a reasonable assurance that cyber devices and related systems are cybersecure.

EU MDR harmonization was originally targeted for May 2024 but postponed to May 2028. Despite this delay, Notified Bodies and Competent Authorities universally recognize it as "state of the art" for health software cybersecurity under MDR GSPR Annex I, Section 17.2. Missing or inadequate cybersecurity documentation is already a top cause of Notified Body major non-conformities for SaMD. A December 2025 Interpretation Sheet (ISH1:2025) clarified software item classification into maintained, supported, and required software categories, affecting risk transfer and post-market obligations.