Sthenos

Quantum Cryptography Engineer

Sthenos AI is the AI developer of EFA Group, building intelligent, mission-ready solutions for defense and aerospace. With deep expertise in Command-and-Control (C2), cyber defense, computer vision, and autonomous systems, we design and deploy secure, field-proven AI that enhances operational efficiency and situational awareness. As part of a leading European defense ecosystem, we bring scalable innovation where it matters most — in the theater of operations.

As a Quantum Cryptography Engineer you lead the implementation, integration and continuous improvement of cryptographic capabilities at Sthenos AI for defense and dual-use applications. You support secure software delivery, FIPS-oriented validation work and collaboration with internal teams, external partners and quantum technology specialists

Your Tasks 

• You lead the secure implementation and review of cryptographic modules for defense and dual-use software systems. 
• You implement cryptographic primitives and security-critical components/ 
• You support the implementation of FIPS-approved algorithms and protocols, including validation and certification activities. 
• You drive iterative hardening, optimization, refactoring and long-term maintenance of cryptographic components. 
• You contribute to the integration of PRNGs, TRNGs, PQC algorithms and QKD-related protocols into our security stack. 
• You collaborate with software, systems and security teams to translate operational requirements into robust implementations. 
• You perform cryptographic code reviews and security assessments and propose practical improvements. 
• You contribute to technical documentation covering architecture, testing, validation evidence and operational use. 
• You participate in EDF calls, proposal-related activities and technical meetings. 
• You work closely with a Quantum Technologies Specialist and other domain experts on quantum-related security objectives. 
• You stay current with applied cryptography, implementation techniques, attack models and evolving standards. 

Your Skills

• MSc or equivalent advanced degree in Cryptography, Computer Science, Mathematics, Electrical Engineering, Cybersecurity or a related field. 
• Significant professional experience in applied cryptography, with strong focus on secure implementation and engineering review. 
• Deep knowledge of modern cryptographic primitives, including encryption, hashing, signatures, key exchange, KDFs and randomness generation. 
• Strong hands-on experience developing security-sensitive software. 
• Experience implementing FIPS-approved algorithms and protocols. 
• Experience supporting validation and certification oriented development. 
• Familiarity with PRNGs and TRNGs in security-critical systems. 
• Good practical understanding of PQC-related algorithms and implementation considerations. 
• Awareness of QKD-related protocols and their operational integration challenges. 
• Familiarity with MBSE and secure SDLC practices is highly advantageous. 
• Eligibility to acquire EU and/or NATO security clearances is mandatory. 

Your Competencies 

• Implementation-driven mindset, able to translate advanced cryptographic theory into robust software. 
• Strong ownership and leadership skills; you can guide complex technical workstreams across teams. 
• High rigor and attention to detail when working on security-critical code and certification-oriented deliverables. 
• Excellent communicator, with the ability to explain effectively the tradeoffs of different cryptographic solutions to a variety of technical and non-technical audiences. 
• Collaborative approach to working with software engineers, systems engineers, security specialists and quantum technology experts. 
• Ability to operate effectively in high-assurance, defense-related environments with evolving requirements. 
• Curious and adaptable, with the drive to continuously improve cryptographic components over time. 

We Offer

• Competitive remuneration package 
• Private medical insurance package
• Continuous learning & development opportunities
• Participation in cultural and team-building activities
• Exposure to a growing environment with cutting-edge technologies
• Corporate wellness initiatives