Senior Cryptography & Mobile Security Engineer

Company Description Hexon is focused on building secure, resilient systems that underpin modern conflict and defense operations in an increasingly digital world. The company develops advanced technologies that enable secure communication, data protection, and operational integrity in high-risk, high-stakes environments. Team members work on mission-driven products where security, reliability, and performance are critical. Hexon values technical excellence, thoughtful engineering, and the ability to innovate under real-world constraints, offering experienced professionals the opportunity to shape the future of defense technology.

Role Description The Senior Cryptography & Mobile Security Engineer is a full-time remote role responsible for designing, implementing, and reviewing cryptographic protocols and mobile security architectures for Hexon’s core systems. Day-to-day work includes developing secure mobile applications and SDKs, performing threat modeling and security assessments, and ensuring robust end-to-end encryption and key management. The role involves collaborating with product and infrastructure teams to integrate security best practices, conducting code reviews focused on cryptographic and security logic, and responding to emerging vulnerabilities with timely mitigation strategies. The engineer will also contribute to security standards, documentation, and internal guidelines to improve the security posture across the organization.

Qualifications

• Strong expertise in applied cryptography, including encryption schemes, key exchange protocols, digital signatures, and secure key management.
• Proficiency in mobile security engineering for iOS and/or Android, including secure app architecture, secure storage, and protection against reverse engineering and tampering.
• Hands-on experience with secure coding practices in languages commonly used for mobile and systems development (such as Swift, Kotlin, C/C++, Rust, or Go).
• Demonstrated ability in threat modeling, vulnerability analysis, and security review of mobile applications, APIs, and backend services.
• Knowledge of modern security standards and frameworks (e.g., TLS, OAuth2/OpenID Connect, end-to-end encryption protocols, hardware-backed security modules).
• Experience working with security tooling and processes, including static and dynamic analysis tools, penetration testing methodologies, and secure CI/CD practices.
• Excellent analytical, problem-solving, and communication skills, with the ability to explain complex security concepts to technical and non-technical stakeholders.
• Ability to work independently in a remote environment, collaborate effectively across distributed teams, and take ownership of critical security components.
• Bachelor’s or advanced degree in Computer Science, Computer Engineering, Mathematics, or a related technical field, or equivalent practical experience.
• Prior experience in security-critical domains such as defense, secure communications, or high-assurance systems is highly beneficial.