Trinity Term 2026 Strachey Lecture with Professor Srđan Čapkun, Hardening Digital Infrastructure: Resilient Positioning and Sovereign Smartphone Architectures. Recent global events have underscored how failures in isolation, redundancy, and control can jeopardiseessential digital functions. A critical challenge remains: how do we harden systems for higher resiliency, personal and societal control while maintaining compatibility with existing ecosystems? In this talk, I explore this in two example settings.

First, I address the systemic vulnerabilities of current satellite positioning systems. By integrating novel protocols hardened at the physical layer, I demonstrate a path toward a robust, feature-rich, wide-area positioning infrastructure.

Second, I introduce a novel security architecture that brings true digital sovereignty to the modern smartphone. This deployable design allows users to run 'several phones in one' (e.g. isolating private and business environments), ensuring that sensitive applications and critical I/O remain protected even if the underlying OS is compromised. Ultimately, these designs return control to users and organisations, fostering a more resilient and free environment for digital innovation.