Operator’s Trusted Repeater successfully demonstrates quantum cryptography over 112km fibre network.

SK Telecom on Monday successfully tested a new fibre optic repeater that enables network traffic encrypted using quantum key distribution (QKD) to be carried over longer distances, paving the way for highly-secure communications.

Called Trusted Repeater, it successfully carried data over 112 kilometres on a roundtrip of the operator’s test network. Prior to this demo, the maximum distance achieved was 80 kilometres, which SK Telecom said represented the biggest obstacle to its commercialisation.

"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, SVP and head of SK Telecom’s network technology R&D centre.

Securing communications has become critically important with networks playing a role in every facet of life, and as cyber attacks become more sophisticated and damaging.

QKD, based on quantum cryptography, enables two parties to create and share a random, secret key known only to them. Not only that, but the parties can instantly detect eavesdroppers, because trying to tap into a quantum system introduces anomalies into said system.

This is far more secure than current methods, such as public and private keys, and digital certificates, because public and private keys can potentially be accessed and copied, while hackers are also capable of mimicking digital certificates.

SK Telecom said its plans to work with partners to roll out its Trusted Repeater on its LTE networks in Korea, plus commercial networks overseas.

"SK Telecom will continue to focus on developing key quantum cryptography technologies and building the related ecosystem," Park said.