In the world of medical devices, cybersecurity isn’t just about protecting information—it’s about protecting patients. One concept that plays a vital role in ensuring both safety and trust is nonrepudiation.
What is Nonrepudiation?
Nonrepudiation ensures that the origin and integrity of data or actions cannot be denied. In healthcare, this means being able to prove:
- A diagnostic device generated specific results.
- A clinician received and acted upon those results.
- Firmware updates or commands came from an authorized source.
This assurance is critical in medical environments where disputes, errors, or malicious activity could directly impact patient outcomes.
Why Nonrepudiation Matters for Medical Devices
Unlike many industries, healthcare cybersecurity extends beyond financial or reputational damage. A compromised device could lead to:
- Misdiagnosis if test results are altered.
- Delayed treatment if records can’t be trusted.
- Direct harm if infusion pumps, pacemakers, or surgical robots receive spoofed commands.
By guaranteeing that device actions and data cannot be denied or manipulated, nonrepudiation helps prevent these risks. It also ensures accountability across the healthcare ecosystem—from device manufacturers to clinicians to IT staff maintaining hospital networks.
Real-World Lessons
We’ve already seen how cybersecurity failures in healthcare can cascade into patient harm. The WannaCry ransomware attack in 2017 shut down hospital systems across the globe, delaying care and forcing patient diversions. More recently, vulnerabilities in connected insulin pumps and pacemakers have shown that attackers could potentially alter treatment delivery. In each case, clear evidence of data origin, logs, and digital signatures could have helped maintain trust and safety.
Nonrepudiation mechanisms don’t just prevent attacks—they provide investigators, regulators, and clinicians with assurance when things go wrong.
How Nonrepudiation is Implemented
Medical device manufacturers can embed nonrepudiation through:
- Digital signatures to authenticate software updates, device logs, and diagnostic outputs.
- Timestamping to provide auditable proof of when actions occurred—critical for both patient care and regulatory compliance.
- Secure audit trails that record user actions and system events, ensuring accountability across the total product lifecycle (TPLC).
- Public Key Infrastructure (PKI) to bind digital certificates to device identities and user accounts.
In more advanced systems, hardware security modules (HSMs) or blockchain-based logs are being explored to strengthen trust and immutability.
Challenges for Medical Device Manufacturers
Implementing nonrepudiation in medical devices is not without hurdles:
- Resource constraints in embedded systems may make cryptographic operations challenging.
- Legacy devices often lack secure logging or update mechanisms.
- Balancing usability and workflow efficiency with strong authentication requirements can be difficult in fast-paced clinical environments.
Despite these challenges, FDA guidance makes it clear: cybersecurity is inseparable from device safety.
The Regulatory Connection
The FDA’s latest cybersecurity guidance emphasizes that cybersecurity is part of device safety. Mechanisms like nonrepudiation directly support this by ensuring that only validated, authenticated actions affect device performance. They also provide evidentiary support during investigations, litigation, or recalls.
The Secure Product Development Framework (SPDF) is one way to structure these protections throughout the product lifecycle. By integrating nonrepudiation into design controls, manufacturers demonstrate not only regulatory compliance but also a commitment to patient safety.
Nonrepudiation also aligns with broader frameworks like the NIST Cybersecurity Framework, IEC 81001-5-1, and IMDRF’s cybersecurity principles, ensuring that devices meet both U.S. and international expectations.
Nonrepudiation Across the Total Product Lifecycle
Nonrepudiation plays a role at every stage of the TPLC:
- Premarket: Validating that software, updates, and logs are authentic as part of FDA submissions.
- Deployment: Ensuring hospitals and clinicians can trust that device data and actions originate from authorized sources.
- Postmarket: Providing secure logs and evidence trails for monitoring, patching, and incident investigations.
- End-of-life: Guaranteeing that decommissioned devices cannot be reintroduced with falsified credentials or altered histories.
Practical Steps for Manufacturers
Medical device manufacturers preparing for FDA submissions should:
- Incorporate nonrepudiation mechanisms into design and validation processes.
- Document digital signature, logging, and timestamping methods in cybersecurity files.
- Ensure SBOM (Software Bill of Materials) integrity checks align with nonrepudiation principles.
- Provide clear labeling and instructions so healthcare facilities can configure devices securely.
These steps not only support regulatory approval but also strengthen trust with healthcare providers and patients.
Bottom Line
For medical device cybersecurity, nonrepudiation isn’t optional—it’s a patient safety requirement. It builds the trust necessary for clinicians, patients, and regulators to rely on device data and functionality. It provides the evidentiary backbone needed for compliance, investigations, and patient care.
At Blue Goat Cyber, we help manufacturers implement robust measures like nonrepudiation as part of a Secure Product Development Framework (SPDF), ensuring devices are secure by design, compliant, and most importantly—safe for patients.