SK Telecom today announced that it has achieved a meaningful milestone in the field of quantum cryptography* technologies by developing Trusted Repeater, a powerful quantum repeater that can dramatically extend the distance of quantum communication, and successfully testing its performance over a trial optical fiber network deployed between Bundang, Yongin and Suwon.

* The quantum cryptography communication is known as the most secure form of communication encryption that cannot be broken with any existing hacking technology. Quantum cryptography is expected to replace the existing security solutions in all areas at risk of data hacking, including national defense, finance, autonomous vehicle and IoT.

With Trusted Repeater, the company has extended the distance record for Quantum Key Distribution (QKD) to 112 kilometers. Prior to the development of this quantum repeater, the maximum transmission distance of QKD remained at around 80 kilometers due to the fact that it involves the use of weak single-photon quantum signals. Therefore, the distance limitation of QKD had been viewed as the biggest obstacle to its commercialization.

Now, thanks to Trusted Repeater, SK Telecom will be able to dramatically extend the distance of QKD: For instance, the company will be able to transmit quantum keys from Seoul to Busan, which is approximately 460 kilometers, by simply installing five units of its repeaters. The company plans to work with its global partners to apply quantum cryptography solutions, including the quantum repeater, to not only to its commercial LTE networks in Korea, but also to commercial networks overseas.

SK Telecom has applied its quantum cryptography technologies to commercial LTE network (fiber optic cable) in Sejong City in 2016 and some parts of the advanced science and technology research network (SuperSiReN) in Daedeok Research Development Complex through cooperation with the Korea Institute of Science and Technology Information (KISTI) in May 2017.

SK Telecom has been actively developing core quantum cryptography technologies since it established Quantum Tech. Lab in 2011. Moreover, in February 2017, it has entered into an agreement with Nokia to cooperate in the quantum cryptography business and established Quantum Alliance with Deutsche Telekom with the aim to enable secure communication in the age of quantum computing.

“SK Telecom has opened a new chapter in the field of quantum technologies by developing the Trusted Repeater, an enabler for long-distance quantum communication,” said Park Jin-hyo, Senior Vice President and Head of Network Technology R&D Center of SK Telecom. “SK Telecom will continue to focus on developing key quantum cryptography technologies and building a related ecosystem.”