Staff Cryptography Engineer

IonQ, a publicly traded leader in quantum technologies, builds integrated solutions for computing, networking, sensing and security. Its latest hardware, the IonQ Tempo, powers breakthroughs for partners such as Amazon Web Services and AstraZeneca. The company operates worldwide, with its headquarters in College Park, Maryland, and a presence across Europe and Asia. This opening is for a Staff Cryptography Engineer who will work on‑site in Geneva, Switzerland, contributing to the company's post‑quantum cryptography (PQC) acceleration efforts for hardware security modules and network appliances. The day‑to‑day work revolves around creating and maintaining both reference and bit‑accurate implementations of algorithms such as ML‑KEM, ML‑DSA and SLH‑DSA/LMS. Development will be carried out in C, C++ or Rust, with occasional Python for testing. The engineer will produce constant‑time code, construct known‑answer‑test suites and generate test vectors that satisfy NIST ACVP requirements, and assist hardware and firmware teams by breaking algorithms into hardware‑friendly components like Keccak, NTT and polynomial arithmetic. Collaboration with senior cryptographers and support for RTL engineers are also key parts of the role. Candidates must hold a master's degree in cryptography, mathematics, computer science or a closely related discipline, with a doctorate viewed as a plus. At least five years of hands‑on experience writing cryptographic or security‑critical software in C, C++ or Rust is required, together with a solid understanding of modern cryptographic primitives. Fluency in English is mandatory, and the ability to produce well‑tested, readable, constant‑time code is expected. The position also calls for strong problem‑solving skills and the capacity to support certification‑oriented development. The role offers the chance to deepen expertise in post‑quantum schemes while working alongside world‑class cryptographers in a fast‑growing quantum company. Geneva provides a central European location with easy access to a global team. IonQ supplies a competitive salary, equity, comprehensive health benefits, unlimited vacation, parental leave and a technology stipend, alongside flexible work arrangements and a clear career‑development pathway. What the role asks for: - Master's degree in cryptography, mathematics, computer science or related (PhD preferred) - Minimum five years developing cryptographic or security‑critical software - Proficient in C, C++ and/or Rust programming - Strong grasp of modern cryptographic primitives - Fluent in English - Experience with lattice‑based or hash‑based post‑quantum algorithms (nice‑to‑have) - Familiarity with NIST test‑vector formats and CAVP/ACVP processes (nice‑to‑have) - Ability to communicate in French or German (advantage)