LONDON, Oct. 20, 2026 (GLOBE NEWSWIRE) -- 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, General Manager 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."

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

Media relations enquiries:
Arqit: Arqit@brands2life.com

Investor relations enquiries:
Arqit: investorrelations@arqit.uk

Caution About Forward-Looking Statements
This communication includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, may be forward-looking statements. These forward-looking statements are based on Arqit’s expectations and beliefs concerning future events and involve risks and uncertainties that may cause actual results to differ materially from current expectations. These factors are difficult to predict accurately and may be beyond Arqit’s control. Forward-looking statements in this communication or elsewhere speak only as of the date made. New uncertainties and risks arise from time to time, and it is impossible for Arqit to predict these events or how they may affect it. Except as required by law, Arqit does not have any duty to, and does not intend to, update or revise the forward-looking statements in this communication or elsewhere after the date this communication is issued. In light of these risks and uncertainties, investors should keep in mind that results, events or developments discussed in any forward-looking statement made in this communication may not occur. Uncertainties and risk factors that could affect Arqit’s future performance and cause results to differ from the forward-looking statements in this release include, but are not limited to: (i) the outcome of any legal proceedings that may be instituted against Arqit, (ii) the ability to maintain the listing of Arqit’s securities on a national securities exchange, (iii) changes in the competitive and regulated industries in which Arqit operates, variations in operating performance across competitors and changes in laws and regulations affecting Arqit’s business, (iv) the ability to implement business plans, forecasts, and other expectations, and identify and realise additional opportunities, (v) the potential inability of Arqit to successfully deliver its operational technology, (vi) the risk of interruption or failure of Arqit’s information technology and communications system, (vii) the enforceability of Arqit’s intellectual property, (viii) market and other conditions, and (ix) other risks and uncertainties set forth in the sections entitled “Risk Factors” and “Cautionary Note Regarding Forward-Looking Statements” in Arqit’s annual report on Form 20-F (the “Form 20-F”), filed with the U.S. Securities and Exchange Commission (the “SEC”) on 9 December 2025 and in subsequent filings with the SEC. While the list of factors discussed above and in the Form 20-F and other SEC filings are considered representative, no such list should be considered to be a complete statement of all potential risks and uncertainties. Unlisted factors may present significant additional obstacles to the realisation of forward-looking statements.