Nicolas Harnois developed a security-focused feature for the canonical/snapd repository, enhancing the image-building workflow by tightening the handling of system-user extra assertions. He implemented logic in Go to restrict authentication to public-key methods and applied these controls exclusively to 'dangerous' model grades, reducing the attack surface during image creation. By updating the seed writer, Nicolas ensured system-user assertions are separated and placed in auto-import.assert for first boot import, improving both reliability and traceability at boot time. His work demonstrated depth in assertion handling, system programming, and testing, delivering measurable improvements in secure-by-default image builds and maintainability.