Deep, expert-level PKI knowledge with hands-on experience designing and operating PKI for embedded and resource-constrained systems -certificate-based device authentication, firmware signing certificate chains, secure boot PKI hierarchies, certificate provisioning and rotation for constrained devices (where rotation isn't trivial, e.g., spacecraft in orbit), secure key storage, and HSM integration. Demonstrated principal-level impact: setting security strategy and technical direction across an organization, independently identifying and prioritizing the risks that matter most, driving hardening initiatives end to end, raising the security bar and mentoring other engineers, thriving on ambiguous and novel problems, and influencing and aligning teams without direct authority.