Lead Rust Developer

Office : Toulouse or Paris (remote work possible) ⏳Length : Full time contract Start date : ASAP Who are we ? We are CYSEC, a fast-growing European information security company based in Luxembourg, Switzerland, and France. We bring security solutions to protect sensitive information and datalinks, on Earth and in Space. We develop and offer three different innovative products securing: ARCA SATLINK - The space data link between the Ground Station and the Satellite ARCA SATCOM - The satcom link providing internet connectivity to end users through satellites ARCA Trusted OS - IT execution environments on untrusted or third party infrastructures We’re a team of engineers and software security experts, combining deep technical expertise with hands-on industry experience. Our mission is to deliver agile, cutting-edge security solutions tailored for even the most exotic infrastructures and we're always ready to tackle the toughest challenges. As a proud multinational and multilingual team, we believe that true innovation and excellence are driven by diversity and inclusion. Join us in shaping the future of cybersecurity. Find out more at: Your Mission As a Senior Rust Developer, you will design and build high-performance software for our satellite VPN platform, from low-level protocol architecture to production deployment. You will play a key role in optimizing network performance over real satellite links, ensuring robustness, efficiency, and security across all layers of the system. Working closely with security experts, product teams, and pre-sales, you will contribute to continuously improving ARCA SATCOM and supporting next-generation satellite communication systems. Key Responsibilities Design and develop high-performance systems in Rust (protocol design to production) Optimize network performance (throughput, stability, resilience) over satellite links Collaborate with cybersecurity experts to ensure strong cryptographic and security standards Drive architectural improvements and contribute to product evolution Work closely with product and pre-sales teams to align technical capabilities with user needs Support integration and deployment of satellite communication systems What We’re Looking For: To strengthen the engineering and innovation teams and to support the growth of the company, we are looking for a Senior Satcom/Network Developer to contribute to CYSEC’s effort in driving cybersecurity innovation for satellite communication Education: Degree in Computer Science, Electrical Engineering, or equivalent hands-on experience Core profile: Expert-level Rust (systems programming, async with Tokio, software architecture) Strong Linux knowledge (kernel, networking stack, TCP/IP, UDP, Netfilter) Advanced networking expertise (congestion control, QoS, routing, VPN, QUIC, bufferbloat) Fluent French and professional English Nice to have: Experience with satellite communications (link budgets, modulation) Knowledge of cryptography and secure protocols (TLS, IPSec) Contributions to open-source Rust projects DevOps experience (Ansible, Terraform, GitLab CI/CD) Mindset Proactive and ownership-driven Strong critical thinking and problem-solving skills Collaborative and team-oriented Why This Role Matters ARCA SATCOM is CYSEC’s flagship satellite communication product, combining end-to-end TLS 1.3 encryption with Split-TCP optimization to boost throughput by up to 250% over LEO and GEO satellite links. Already deployed across Europe, the Middle East, and Africa, it supports critical communications for defense, government, and commercial networks. In this context, your role is key to ensuring the performance, reliability, and security of these deployments. You will directly contribute to solving real-world challenges in satellite connectivity, improving how secure communications operate in constrained and high-latency environments, and enabling CYSEC’s technology to scale across global infrastructures