Senior Cryptography Engineer

IonQ, Inc. is the world's leading quantum‑platform provider, delivering integrated solutions for computing, networking, sensing and security. Through its ID Quantique (IDQ) division, the company offers quantum‑safe communications that protect governments, telecom networks and financial institutions. This senior‑level position is based onsite in Geneva, Switzerland, and joins a team that builds post‑quantum cryptography (PQC) hardware acceleration for hardware security modules and network‑appliance products. On a daily basis the engineer will create and maintain reference and bit‑accurate models of the ML‑KEM, ML‑DSA and SLH‑DSA/LMS algorithms using C, C++, Rust and Python. The role also involves writing constant‑time software implementations of cryptographic primitives, constructing known‑answer‑test and test‑vector tooling that complies with NIST ACVP standards, and supporting verification and CAVP certification efforts. In addition, the engineer will help break down algorithms into hardware‑friendly components such as Keccak, NTT, polynomial arithmetic, samplers and encode/decode blocks, and will provide algorithmic expertise and debugging assistance to RTL and firmware teams while evaluating third‑party cryptographic libraries under the guidance of senior cryptographers. The position requires a Master's degree in Cryptography, Mathematics, Computer Science or a closely related discipline (a PhD is considered a plus) and a minimum of five years' experience developing cryptographic or security‑critical software in C, C++ or Rust. Candidates must possess a solid grounding in modern cryptographic primitives and demonstrate an understanding of constant‑time implementation practices. Fluency in English is mandatory; additional language skills in French or German are advantageous. A proven ability to produce well‑tested, readable code and a focus on correctness are essential. Preferred, but not mandatory, qualifications include familiarity with NIST test‑vector formats, CAVP/ACVP certification processes, and prior exposure to lattice‑based or hash‑based post‑quantum schemes. The role offers the chance to work alongside some of the most experienced cryptographic engineers in the field and to develop deep expertise in applied cryptography, positioning the successful candidate for growth into a world‑class applied cryptographer. What the role asks for: - Master's degree in Cryptography, Mathematics, Computer Science or related field - 5+ years experience implementing cryptographic or security‑critical software in C/C++/Rust - Strong foundation in modern cryptographic primitives and post‑quantum concepts - Fluency in English - Familiarity with NIST test‑vector formats and CAVP/ACVP (nice‑to‑have) - Fluency in French or German (nice‑to‑have) - Experience with lattice‑based or hash‑based PQ schemes (nice‑to‑have) - Desire to become a world‑class applied cryptographer (nice‑to‑have)