About Vinci Every physical thing you touch exists because somebody successfully navigated the laws of physics: the chips in your phone, the vehicles on the road, the data centers powering AI. Physics determines what can be built, how well it performs, and where it breaks. Yet the tools engineers use to understand physical behavior are too slow and too specialized to use continuously while designing, so critical decisions get made with only a partial view of how a system will behave. Vinci is building a Foundation Model for Physics. Our mission is to make physical reasoning as accessible to engineers as language became through modern AI. This is not an attempt to build slightly better engineering software. It is an attempt to change how physical products are designed. Our technology is used today by many of the world's most advanced semiconductor and electronics organizations, including nearly half of the twenty largest companies in the industry. We are backed by Khosla Ventures and Eclipse Ventures. The role Simulating complex physical systems increasingly means coordinating computation across multiple systems. We are hiring the engineer who will design and own the protocol that makes that coordination possible: the wire format, the identity model, and the trust model. This is a broad challenge that touches everything from how our solutions work to how to maintain security compliance. Coordinating computation across systems that by design may not fully trust each other is not access control with extra steps. The protocol has to be something a security audit can evaluate and approve, which means the guarantees have to be real and they have to be explainable. You will work on this alongside the physicists and numerical engineers who built our solvers, and the full stack engineers who build the applications.. What you'll do • Design the protocol for cross-system communication: schema, versioning, and negotiation, built so future capabilities extend it rather than break it • Own the secure transport and service identity layer, including certificate, key, and credential design • Define the trust model: what each participant discloses, what it can infer, and how that is documented for a customer's security review • Threat-model the protocol itself, not only its transport, including replay, resource exhaustion, and inference across repeated interactions • Partner with our solver, orchestration, and product engineers so that security constraints shape architecture early rather than arriving as review comments • Represent our security posture to customers and manage external penetration testing What we're looking for • Experience designing and shipping network protocols or service-to-service APIs that outlived their first version, with concrete opinions on schema evolution and backward compatibility • Depth in applied transport and authentication security: TLS and mTLS in practice, certificate and key handling, service identity, credential design • Experience with authorization models that had to evolve as requirements grew • Comfort reasoning about what a system reveals, not only what it permits • Clear written communication: much of this role's output is documentation that other engineers and customers rely on Nice to have • gRPC and Protocol Buffers at scale • Multi-tenant or cross-organizational systems where the tenants do not trust each other • Privacy engineering, secure multiparty computation, or confidential computing • Simulation, CAD, EDA, robotics, or another domain with large geometric or numerical payloads Is this you? This is a back end engineering role with security at its center, not an infrastructure or compliance security role. If your career has mostly been securing and auditing systems other people designed, this is probably not the right fit. If you have designed services that had to be secure by design, it likely is.