Lessons Learned from Deploying LMS at Scale

Stateful hash-based signatures such as LMS are standardised and well understood, but translating them into deployable products involves challenges that are often absent from standards and academic literature.

This talk discusses the practical realities of deploying a stateful hash-based scheme in long-lived hardware-rooted systems. Drawing on experience securing firmware update mechanisms in commercial PCs and printers, it explores how standards guidance, hardware lifecycles, resilience requirements, certification considerations and business constraints influenced key design decisions.

It covers lessons from adopting the LMS standard into security features deployed at scale, including the challenges of balancing security, resilience, certification and operational requirements, and reflects on how later developments in standards, certification programmes and industry guidance reinforced, challenged or reshaped those decisions, and what this means for future quantum-resistant migrations.