The Secure Development Lifecycle

The secure development lifecycle builds security into every phase of software development, from requirements through release, instead of treating it as a final checkpoint. For medical devices, FDA expects this to take the form of a Secure Product Development Framework, and your existing design controls under 21 CFR 820.30 are the natural home for it.

4.2.1 What Makes Development "Secure"?

According to the FDA's 2023 premarket cybersecurity guidance, secure development means following a Secure Product Development Framework (SPDF). The guidance defines this as "a set of processes that reduce the number and severity of vulnerabilities in products."

This isn't about adding security checkpoints to your existing process. It's about weaving security into every development activity:

• Requirements: Include security requirements alongside functional ones
• Design: Consider security in architecture decisions
• Implementation: Follow secure coding practices
• Testing: Verify security controls work
• Release: Ensure secure deployment

4.2.2 Key Principles of Secure Development

The Joint Security Plan (JSP) outlines several core principles:

Security by Design

• Build security in, don't bolt it on
• Consider security in every decision
• Design for the full lifecycle

Defense in Depth

• Multiple layers of protection
• No single point of failure
• Overlapping controls

Least Privilege

• Minimal necessary permissions
• Restricted access by default
• Privilege separation

Fail Secure

• Safe behavior during errors
• Secure defaults
• Graceful degradation

4.2.3 Integrating with Your QMS

Secure development doesn't replace your Quality Management System (QMS) - it enhances it. Under 21 CFR 820.30 (Design Controls), security becomes part of:

• Design Input: Security requirements
• Design Output: Security specifications
• Design Review: Security assessments
• Design Verification: Security testing
• Design Validation: Security effectiveness
• Design Changes: Security impact analysis

For a stage-by-stage mapping of security activities to the FDA artifacts they produce, see How to implement a secure software development lifecycle for medical devices. For how SPDF coexists with IEC 62304, see SPDF vs IEC 62304.