Investment builds on successful joint deployments to accelerate product development and expand into new defence markets
London, U.K. – 20 October 2026 – Arqit Quantum Inc. (NASDAQ: ARQQ), a global leader in quantum-safe encryption helping safeguard sensitive information from current and future cyber threats, today announced a strategic investment in Sirius Computer, Inc., a technology provider of secure computing and networking solutions for defence, intelligence and critical national infrastructure. This will accelerate the development and delivery of quantum-safe communications for defence, government and national security users.
The investment builds on an existing partnership that combines Sirius’s secure networking technology with Arqit’s Sovereign Key Platform (SKP) and NetworkSecure adaptors to deliver Crux, a software-based connectivity platform. The companies’ joint offering protects sensitive communications across devices and networks, helping defence users share information securely in deployed environments, and when operating alongside allied forces.
The software-based offering is designed to run on commercial devices and work alongside existing infrastructure, enabling users to extend secure communications without replacing their underlying networks. Applications include mobile devices, cloud and network systems, autonomous platforms such as Uncrewed Autonomous Vehicles (UAVs) and their associated control systems.
The strategic investment will support the continued development of Crux and Sirius’s broader software and hardware technologies, deeper integration with Arqit's encryption solutions, and the creation of new joint products and services. The companies have been selected as part of a winning bidding consortium to provide secure networking services to NATO. The companies will also expand their joint go-to-market activities, pursuing opportunities across NATO member countries and other allied nations, including the UK Ministry of Defence and US Department of Defense.
Paul Feenan, GM for Defence & Government at Arqit, said: “Defence organisations face a difficult balance between getting critical information to the people and platforms that need it, while keeping it out of adversaries’ hands. When forces operate alongside allies, that challenge extends across national boundaries and different technologies. Security needs to support that cooperation without adding complexity for personnel on the ground. It also needs to protect information whose sensitivity will outlast the operation itself. Investing in Sirius will help us build on our existing partnership to make quantum-safe communications easier to deploy and extend to more defence users.”
Jason Van der Schyff, Co-Founder and Chief Executive Officer of Sirius, said: "We've built Sirius around the belief that secure communications shouldn't depend on complex, expensive infrastructure that is difficult to deploy and maintain. Our partnership with Arqit has already demonstrated what's possible when advanced encryption enhances lightweight, adaptable networking technology. This investment is a significant vote of confidence in our team and our technology, and gives us the resources to accelerate development, expand our capabilities and bring these solutions to more defence and government customers around the world."
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About Arqit
Arqit Quantum Inc. (Nasdaq: ARQQ) secures the world’s most critical data with quantum-safe encryption software. Simple, scalable, and compliant, its products integrate with existing infrastructure, and require no rip and replace of hardware.
Arqit provides a complete “Detect, Protect, Comply” solution for governments and enterprises that detects and inventories cryptographic assets, protects data, ensures compliance, and safeguards transition to the post-quantum era.
Arqit’s primary product offerings are Encryption Intelligence and NetworkSecure™. Encryption Intelligence detects cryptographic exposure, identifies vulnerabilities, and maps dependencies. NetworkSecure™ protects data in transit with provably secure post-quantum cryptography and contributes to establishment of confidential compute environments for complete data sovereignty.
Arqit is an IDC Innovator for Post-Quantum Cryptography (2024) and a multi-award-winner in quantum-safe security.
For more information, visit www.arqitgroup.com.
About Sirius
Sirius Computer, Inc., develops secure computing and networking solutions for defence, intelligence and critical national infrastructure. Its flagship product, Crux, delivers lightweight, quantum-safe secure communications across mobile devices, computers and embedded systems, enabling organisations to protect sensitive information without replacing existing network infrastructure.
Designed for demanding operational environments, Sirius technologies support secure connectivity across distributed teams, autonomous platforms and deployed networks. Sirius has undertaken UK Government-supported research and development through HMGCC's Co-Creation programme and was named a finalist in the Startup in Cyber category at the 2026 National Cyber Awards.
Sirius operates across the United States, United Kingdom and Germany.
For more information, visit www.sirius.computer