PacketLight and Toshiba demonstrate quantum key distribution (QKD) over DWDM links

The universities, the technology-edge universities, would like to show quantum encryption. It's one of their highlights. So, together with Toshiba and them, we did it over a 70-kilometer link and demoed it at the Sapporo show.

The link performance was measured using a 100G tester, showing 100% throughput and low latency in compliance with the RFC2544 standard. RFC2544 is the industry-standard service activation test for single-service Ethernet and IP. The test measures critical performance indicators and bandwidth profiles such as throughput, latency, packet Jitter, frame loss, and committed burst size (CBS).

Through a partnership with NICT in Japan, Toshiba’s multiplexed QKD system in Sapporo utilized PacketLight’s PL-4000M Muxponder to transmit a 400G wavelength, with the Quantum channel running over 1310 nm.

PacketLight and Toshiba demonstrated that QKD-secured signals can share the same space as classical data transmissions on the same fiber network and show how QKD technology can be deployed on today’s existing networks without needing a separate fiber. Using QKD on existing fiber networks provides significant cost savings and increases deployment speed as it removes the need to use dedicated fiber for QKD transmission.

Reshef said that universities are keen to showcase their quantum research projects.

“The technology edge universities would like to show quantum encryption,” he said. “It's one of their highlights. So, it was together with Toshiba and them, and we did it over the 70-kilometer link and demoed it in the Sapporo show.”

But universities aren’t the only entities interested in quantum technology. PacketLight also demonstrated with Singtel in its lab and customers in Singapore, who Reshef said “are interested in quantum encryption.”

Service provider interest grows

Besides Singtel, several other large Tier 1 service providers, including Bezeq South Korea Telecom, British Telecom, and Bezeq, are showing interest and are starting their quantum trials.

Bezeq recently signed an agreement with HEQA Security, an Israeli cybersecurity vendor specializing in securing data communication with quantum-safe encryption, in anticipation of emerging cyber threats that will arise with the growth of quantum networking. 

Through this partnership, Bezeq will deploy an encryption-critical distribution network, positioning it as the first Israeli telecom to fortify its infrastructure against the burgeoning threat of quantum cyber-attacks. These advanced cyber threats pose significant risks to critical sectors, including finance, healthcare, and defense, underlining the urgency of preemptive security measures. 

“Service providers like SKT, BT Bezeq, and others are looking to make more revenues or unique services, and one of the things that caught their eyes or caught their attention was also the quantum service offering they can offer,” he said. “They want to differentiate their service, or they want to offer something better or unique, so they are going into offering a quantum solution.”

He added that service providers are looking to understand how they can have DWDM systems work with WDM platforms.

“So, all of them are in stages of qualifying different quantum equipment, like Toshiba, IDQ, and others, together with different WDM vendors,” Reshef said. “They will also have the entire ecosystem to offer the service to different WDM equipment vendors, system vendors, and quantum devices.”

Building a quantum/optical ecosystem

PacketLight and other quantum trials show the potential of quantum technology and how quantum equipment providers and WDM equipment providers are working to create a new ecosystem.

Being part of developing quantum computing technology since 1999, Toshiba is familiar with the technology.

“This trial has verified that our technology works when connected to PacketLight's equipment, making it accessible to a broader customer base,” said Shinya Murai, Senior Fellow, QKD Business Development Office, Toshiba Digital Solutions Corporation. “We will continue working with our partners to provide solutions for quantum-safe communications."

Reshef agreed that partnerships with Toshiba will drive openness and cooperation.

“This is how, let's say, a technology starts or matures when you have a healthy ecosystem,” he said. “This is one of the reasons why Toshiba was also pleased to do the test with us because, for them, each WDM vendor or each system vendor that can interoperate with their devices has the potential to create a more enhanced ecosystem.”

The two companies also promote each other’s solutions as part of the agreement. Links to Toshiba and others are on the PacketLight or Toshiba websites.

“Because the idea now is to build an ecosystem with different vendors and systems and let the users, either carriers or universities and so on, go to commercial use with this more matured ecosystem than before,” Reshef said.

Overcoming Challenges

While there is growing interest in quantum computing and encryption, the challenge is dealing with Federal Information Processing Information Standards (FIPS). FIPS is a set of standards defining security requirements for products that implement cryptographic modules to secure sensitive but unclassified information. 

Meanwhile, the National Institute of Standards and Technology (NIST) is developing standards for Quantum cryptography, or quantum encryption, which refers to various cybersecurity methods for encrypting and transmitting secure data based on quantum mechanics' naturally occurring and immutable laws.

Last year,  NIST selected four algorithms designed to withstand quantum computer attacks. 

Reshef said that while it follows FIPS for releasing quantum-related products, the drawback is that it takes considerable time.

“FIPS is a very lengthy process,” he said. “You have an external lab which tests your device and ensures it applies to all the standard FIPS requirements. After the lab conducts the test, they submit it to the US government in the case of FIPS, and then you get the federal approval that it can be used for federal government entities.”

PacketLight and other optical players use the standard encryption, the Diffie-Hellman key exchange, to conduct quantum encryption with the quantum computer.

As conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman—two pioneers in public-key cryptography—the Diffie–Hellman (DH) key exchange is a mathematical method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols. DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography.

“Today, in the standard encryption we do in optical systems, we typically exchange the keys with Diffie-Hellman because this is the FIPS standard for it, or common criteria depending on whether you are in the US or Europe,” Reshef said.

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