Staff Cryptography Engineer

Location: This role is based onsite in Geneva, Switzerland.
Travel:
Job ID: 1919

The Role:

We are looking for a Staff Cryptography Engineer to join our team building post-quantum cryptography (PQC) hardware acceleration for HSM and network-appliance products. You will implement the software side of modern post-quantum algorithms: reference models, optimised implementations, and the test infrastructure that proves they are correct. This is a hands-on development role at the heart of applied cryptography, working with some of the most experienced cryptographic engineers in the field.

Responsibilities:

You will implement and maintain reference and bit-accurate models of ML-KEM, ML-DSA and SLH-DSA/LMS in C/C++/Rust and Python, develop constant-time software implementations of cryptographic functions, and build out the known-answer-test and test-vector tooling (NIST ACVP) used for verification and CAVP certification. You will contribute to the decomposition of algorithms into hardware-friendly building blocks (Keccak, NTT and polynomial arithmetic, samplers, encode/decode), support RTL and firmware engineers with algorithm questions and debugging, and help evaluate third-party cryptographic libraries, working under the guidance of our senior cryptography engineers.

• Implement reference models, optimised software and test-vector infrastructure for ML-KEM, ML-DSA and SLH-DSA/LMS
• Support hardware and firmware teams with algorithm expertise, debugging and certification-oriented tooling

Requirements:

We are looking for a candidate with a Master’s degree (PhD a plus) in Cryptography, Mathematics, Computer Science or a related field and at least five years of experience implementing cryptographic algorithms or security-critical software in C/C++ or Rust. You have solid understanding of modern cryptographic primitives and ideally first exposure to post-quantum schemes (lattice-based or hash-based) and their underlying mathematics.

You care about correctness and write well-tested, readable code; you understand what constant-time implementation means and why it matters. Familiarity with NIST test-vector formats, CAVP/ACVP or certification-oriented development is a plus. Fluency in English is required; French or German is an advantage.

• Hands-on developer of cryptographic or security-critical software with strong C/C++/Rust skills
• Solid cryptographic foundations with the ambition to build deep post-quantum expertise

Preferred Qualifications:

You want to grow into a world-class applied cryptographer by working on real products with demanding correctness and security requirements, and you enjoy the discipline of code that must be provably right.

What We Offer:

• A role at one of the fastest growing and most exciting quantum companies in the world
• A competitive compensation scheme, benefits package, and equity plan designed to reward excellence
• Flexible work models that let you balance your life, your family, and your career
• Ongoing training and development to keep your skills sharp and your growth on track
• A career development plan within the IonQ group’s companies
• A dynamic, close-knit environment where you collaborate with a global team of experts
• A performance-driven culture built on trust, teamwork, and shared ambition