Medical devices | Modelled case study
Qualify post-quantum signing for medical-device secure boot
Can the boot chain verify a new signature scheme within memory, timing, safety, and update constraints?
The modelled organisation
A recognisable problem reaches the operating agenda
This composite scenario follows the Device Security Architect · Firmware Lead · Quality functions. It is grounded in the cited problem context but does not identify a real customer.
Operating environment
A medical-device manufacturer supports embedded products across development, regulatory submission, manufacturing, hospital deployment, servicing, and field update lifecycles.
What is at stake
Trust changes must preserve safe boot and update behavior on constrained devices while maintaining traceability from released software to regulatory evidence.
Situation
A standards-compliant signature implementation does not prove that a constrained device, boot ROM, recovery image, and manufacturing process form a safe deployable trust chain.
Event that forces action
A new device platform, secure-boot redesign, or threat model extending beyond the product's service life.
Concrete system boundary
Systems this case study puts in scope
The model is specific about the operational surfaces that must be discovered, changed, or independently checked.
boot ROM and bootloader
firmware signing service
manufacturing provisioning
field verification and recovery
Modelled case study walkthrough
How this organisation would use QNSI
The walkthrough connects the real-world problem to a bounded QNSI contribution and an independently reviewable result.
Recognise the operating condition
A standards-compliant signature implementation does not prove that a constrained device, boot ROM, recovery image, and manufacturing process form a safe deployable trust chain.
Frame the decision the owners must make
Can the boot chain verify a new signature scheme within memory, timing, safety, and update constraints?
Apply QNSI to the controlled boundary
Use QNSI algorithm and conformance evidence to select candidate signatures and record test results without claiming hardware execution.
Leave the team with a concrete result
A secure-boot qualification dossier covering signer custody, image format, verification timing, rollback, and failure behavior.
Prove the result in the organisation's environment
The manufacturer performs safety analysis, hardware tests, regulatory review, and production-key ceremony validation.
What useful success looks like
A decision artifact plus proof from the real environment
The model stops at a target result. It becomes an actual case study only when a customer produces and independently validates this evidence in production.
Decision artifact
A secure-boot qualification dossier covering signer custody, image format, verification timing, rollback, and failure behavior.
Independent validation boundary
The manufacturer performs safety analysis, hardware tests, regulatory review, and production-key ceremony validation.
Real-world problem grounding
Primary sources behind the model
These sources establish the external requirement, failure mode, or risk context used to model this case. They do not endorse HEOSSI or prove that QNSI completed the scenario.
Customer evidence status
This is modelled, not a customer claim
The organisation is a composite and the result is a target state. This page does not prove a deployment, customer outcome, certification, legal conclusion, regulator endorsement, or completed control.