New York-London trial demonstrates how ultra-high-speed data can remain protected from quantum threats across 6900km of digital infrastructure

Colt Technology Services (Colt), the global digital infrastructure company, and Ciena (NYSE:CIEN), the global leader in high-speed connectivity, have completed one of the fastest quantum-safe data transmissions ever demonstrated and the fastest across a transatlantic route. The landmark trial successfully protected live data running across 6900km of Colt's subsea and terrestrial network between New York and London with Ciena's WaveLogic 6 Extreme (WL6e) encryption solution¹. The trial proved that data can be securely transmitted at an 800Gb Ethernet (GbE) service rate - fast enough to move data-centre-scale volumes across the Atlantic in seconds - while remaining protected against growing quantum threats.

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Businesses are moving now to protect their data from "harvest now, decrypt later" attacks, in which bad actors intercept and store data in transit waiting for future quantum computing capabilities to break through traditional data encryption methods to access it. This could be possible as early as 2030. According to research, 69% of organisations believe quantum computing poses a real risk to current encryption and 46% believe large portions of their data could be compromised². The successful Colt and Ciena trial demonstrates that high-speed quantum-safe connectivity is ready to secure customer data reliably across continents, along one of the world's busiest data corridors.

The trial is the latest in a series of quantum-safe encryption trials led by Colt across transatlantic subsea networks and stands out due to its:

Speed: 800GbE is still at the very early adoption stage as most deployed long-haul and subsea systems today run at 100GbE or 400GbE. The trial successfully showcased an 800GbE encrypted service across the Atlantic on one of the most popular routes in the world
Security: Ciena's WL6e 1.6T quantum-safe encryption solution on the Waveserver platform offers PQC algorithms enabling high-capacity secure connectivity that can function at extreme bandwidths over any distance³.
Performance: the trial demonstrated outstanding optical performance, stability over subsea infrastructure and readiness to secure AI traffic demands

Buddy Bayer, chief operating officer, Colt Technology Services said, "Quantum computing is redefining the security challenge for global connectivity. This trial marks a significant step forward in protecting the world's data as it moves across continents. It proves that quantum-safe protection can be delivered at real-world scale. Colt's infrastructure combines global reach, sustained investment and robust security, giving businesses, hyperscalers and neoscalers the confidence to grow. At the same time, Ciena's quantum-safe solutions show how next-generation security can be embedded into high-speed networks, ensuring protection keeps pace with performance. Together, we're helping customers protect critical data today while preparing for the quantum era, building future-ready networks that simply work, and are secure, scalable and ready to power the AI economy."

Dino DiPerna, senior vice president, Global Research and Development, Ciena said, "As network demand surges, operators are raising the security bar to stay ahead of the threat posed by quantum computers. This Colt-Ciena trial shows how post-quantum cryptography and proven high-performance optical encryption can play an important role in protecting high-speed services over real-world long-haul and submarine networks, helping secure critical in-flight data across any distance."

Following this and other successful optical network trials, Colt can offer quantum-safe services to meet a diverse range of customer needs. These include solutions based on Post-Quantum Cryptography (PQC), Quantum Key Distribution (QKD), Symmetric Key Infrastructure (SKI), and hybrid models, across both terrestrial and subsea networks. The solutions are ideal for organisations including:

Enterprises seeking resilient and secure global connectivity and reducing compliance risk
Global content providers, hyperscalers and neoscalers exploring quantum-safe integration
Financial institutions and healthcare providers requiring robust protection for sensitive data in transit
Government and defence organisations prioritising national security and compliance

Colt and Ciena have a strong track record of collaborating to drive customer success. The latest trial follows an announcement in 2025 highlighting the rollout of a powerful new terabit network to support two hyperscaler customers/global content providers, and the completion of the world's first 1.2 terabit per second wavelength transmission across the Atlantic Ocean, announced by Colt and Ciena in November 2024.

Notes to Editors

¹The solution uses National Institute of Standards and Technology (NIST)-compliant, commercially approved post-quantum cryptography (PQC) algorithms, which means it has been approved by a trusted global standards body as commercially viable.

²DigiCert global enterprise study

³The solution uses a new type of encryption designed to keep data secure against future quantum threats. ML-KEM (Module-Lattice-Based Key-Encapsulation Mechanism) is one of the first PQC methods to be officially standardised and approved by the National Institute of Standards and Technology (NIST) as FIPS 203.

About Colt Technology Services

We're Colt. We own and operate exceptional digital infrastructure which powers the global AI economy, connects societies, builds communities and transforms lives. Thousands of colleagues in 65+ offices across Europe, Asia, and North America share a deep commitment to delivering an outstanding experience and making every interaction effortless for our customers.

Customers and partners choose our award-winning fibre infrastructure, digital platforms and security solutions, delivered across a network that spans continents and crosses oceans. We're Europe's largest B2B operator: we connect 40+ countries, 32,000 enterprise buildings, 275+ points of presence, and 12 cable landing stations and we manage eight subsea cable systems. We also co-manage AS3356 - the most widely peered network in the world.

Founded in London over 30 years ago, we're privately funded and driven by values of fairness, inclusion and equity. We're known for our urgent call for social and sustainable change and we're guided by our purpose in everything we do: creating effortless connections and extraordinary outcomes for our customers, communities and people. Be a part of our story: come on over to www.colt.net or join our amazing communities at LinkedIn, Instagram, TikTok, Facebook and YouTube. Media enquiry? Email us at pressqueries@colt.net.

About Ciena

Ciena is the global leader in high-speed connectivity. We build the world's most advanced networks to support exponential growth in bandwidth demand. By harnessing the power of our networking systems, interconnects, automation software, and services, Ciena revolutionizes data transmission and network management. With unparalleled expertise and innovation, we empower our customers, partners, and communities to thrive in the AI era. For updates on Ciena, follow us on LinkedIn or visit the Ciena website.

Note to Ciena Investors

You are encouraged to review the Investors section of our website, where we routinely post press releases, SEC filings, recent news, financial results, and other announcements. From time to time we exclusively post material information to this website along with other disclosure channels that we use. This press release contains certain forward-looking statements that are based on our current expectations, forecasts, information and assumptions. These statements involve inherent risks and uncertainties. Actual results or outcomes may differ materially from those stated or implied, because of risks and uncertainties, including those detailed in our most recent annual and quarterly reports filed with the SEC. Forward-looking statements include statements regarding our expectations, beliefs, intentions or strategies and can be identified by words such as "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "should," "will," and "would" or similar words. Ciena assumes no obligation to update the information included in this press release, whether as a result of new information, future events or otherwise.

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Elena Fuhrmann

Ciena Corporation

+1 (410) 694-5761

pr@ciena.com

Colt and Ciena Set New Benchmark With Fastest Ever Quantum-Safe Transatlantic Data Transmission