CESNET and Ribbon Achieve Successful Proof of Concept in Quantum-Secured Optical Networking

Demonstrates real-world viability of quantum encryption without performance tradeoffs

PLANO, Texas, April 13, 2026 /PRNewswire/ -- Ribbon Communications Inc. (Nasdaq: RBBN), a global leader in real-time communications technology and IP optical networking solutions, today announced the successful completion of a Quantum Key Distribution (QKD) proof of concept with CESNET, operator of the Czech Republic's national academic computer network. Ribbon is committed to helping service providers, enterprises and critical infrastructure operators worldwide modernize and secure their networks and services.

"Our mission is to ensure the highest level of security for academic and research communications," said Václav Novák, Head of the Network Infrastructure Department, CESNET. "This successful test builds on our long-term partnership with Ribbon and demonstrates that quantum encryption can be deployed in real-world optical networks without compromising performance."

Ribbon's Apollo optical networking system adds Layer 1 optical encryption with virtually zero latency and no overhead, blocking all payload and addressing information. This configuration ensures encrypted DWDM/OTN networks can carry any client service without interoperability issues. Optical encryption is a powerful tool in the fight against unwanted intrusion, and Apollo enables operators to use it internally or offer it as a value-added service to customers.

"QKD represents the future of secure networking," said Christian Erbe, Ribbon's Head of EMEA Sales. "We're proud to support CESNET and deliver a security solution that is virtually impenetrable and ready for the next generation of network threats."

About Ribbon
Ribbon Communications (Nasdaq: RBBN) delivers secure cloud communications and IP and optical networking solutions to service providers, enterprises and critical infrastructure sectors globally. We engage deeply with our customers, helping them modernize their networks for improved competitive positioning and business outcomes in today's smart, always-on and data-hungry world. Our end-to-end portfolio of communications software and IP Optical networking solutions delivers superior value and innovation by leveraging cloud-native architectures, automation and analytics tools, and leading-edge security. We maintain a keen focus on our commitments to Environmental, Social, and Governance (ESG) matters, offering an annual Sustainability Report to our stakeholders. To learn more about Ribbon, please visit rbbn.com

Important Information Regarding Forward-Looking Statements
The information in this release contains forward-looking statements regarding future events that involve risks and uncertainties. All statements other than statements of historical facts contained in this release, including those regarding the expected benefits from use of Ribbon Communication's products, are forward-looking statements. The actual results of Ribbon Communications may differ materially from those contemplated by the forward-looking statements. For further information regarding risks and uncertainties associated with Ribbon Communications' business, please refer to the "Risk Factors" section of Ribbon Communications' most recent annual or quarterly report filed with the SEC. Any forward-looking statements represent Ribbon Communications' views only as of the date on which such statement is made and should not be relied upon as representing Ribbon Communications' views as of any subsequent date. While Ribbon Communications may elect to update forward-looking statements at some point, Ribbon Communications specifically disclaims any obligation to do so.

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