Senior Cryptography Engineer

As a Staff Cryptography Engineer at IonQ (ID Quantique), you will implement the software side of modern post-quantum cryptography algorithms and build hardware acceleration for HSM and network-appliance products. You'll join a team of experienced cryptographic engineers working on applied cryptography at the core of quantum-safe communications, protecting governments, telecommunications infrastructure, and financial institutions from the "harvest-now, decrypt-later" threat.

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) used for verification and CAVP certification
• Contribute to the decomposition of 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
• First exposure to post-quantum schemes (lattice-based or hash-based) and their underlying mathematics
• The ability to write well-tested, readable code with attention to correctness
• An understanding 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
• 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 to balance life, family, and career
• Ongoing training and development
• A career development plan within the IonQ group
• Comprehensive medical, dental, and vision plans
• 401(k) matching, unlimited PTO, and paid holidays
• Parental and adoption leave
• Legal insurance and home technology stipend

About IonQ

IonQ, Inc. (NYSE: IONQ) is the world's leading quantum platform and merchant supplier, delivering integrated quantum solutions across computing, networking, sensing, and security. ID Quantique, part of IonQ, is a global leader in quantum-safe communications, providing solutions to protect governments, telecommunications infrastructure, and financial institutions. The company is headquartered in College Park, Maryland, with operations across North America, Europe, and Asia-Pacific.