Staff Cryptography Engineer

As a Staff Cryptography Engineer at IonQ, you will implement the software side of modern post-quantum cryptography (PQC) algorithms for hardware acceleration in HSM and network-appliance products. You join a team of experienced cryptographic engineers, working on reference models, optimised implementations, and test infrastructure for cutting-edge post-quantum schemes.

What you'll do

• 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
• Build known-answer-test and test-vector tooling (NIST ACVP) for verification and CAVP certification
• Decompose algorithms into hardware-friendly building blocks such as Keccak, NTT and polynomial arithmetic, samplers, and encode/decode functions
• Support RTL and firmware engineers with algorithm expertise, debugging, and certification-oriented tooling
• Evaluate third-party cryptographic libraries under the guidance of senior cryptography engineers

What you bring

• A Master's degree in Cryptography, Mathematics, Computer Science or a related field
• At least five years of hands-on experience implementing cryptographic algorithms or security-critical software in C/C++ or Rust
• A solid understanding of modern cryptographic primitives
• Knowledge of constant-time implementation and why it matters
• Fluency in English

Nice to have

• A PhD in Cryptography, Mathematics, Computer Science or a related field
• First exposure to post-quantum schemes such as lattice-based or hash-based cryptography and their underlying mathematics
• Familiarity with NIST test-vector formats, CAVP/ACVP or certification-oriented development
• Fluency in French or German

What we offer

• Competitive compensation, benefits package, and equity plan
• Flexible work models
• Ongoing training and development
• A career development plan within the IonQ group
• Comprehensive medical, dental, and vision plans
• Matching 401(k), unlimited PTO and paid holidays, parental/adoption leave, legal insurance, and a home technology stipend

About IonQ

IonQ (NYSE: IONQ) is a leading quantum computing platform and merchant supplier delivering integrated quantum solutions across computing, networking, sensing, and security. The company operates globally with offices across North America and Europe, and its quantum computing services are available through all major cloud providers.