South Africa sets up “uncrackable” quantum satellite link with China

Stellenbosch University has announced a record-breaking quantum satellite link between South Africa and China, with encryption the parties described as “unbreakable”.

Scientists from South Africa and China established the link, now the world’s longest intercontinental ultra-secure quantum satellite link at 12,900km.

“Using the Chinese quantum microsatellite Jinan-1, launched into low-Earth orbit, this milestone marks the first-ever quantum satellite communication link established in the Southern Hemisphere,” the university says.

It explained that quantum keys are generated in real-time through Quantum Key Distribution (QKD), enabling secure encryption of images transmitted between China’s and South Africa’s ground stations.

This is achieved via one-time pad encryption, which is considered unbreakable.

Quantum communication leverages the fundamental principles of quantum mechanics, promising highly secure information transfer.

QKD uses single photons to encode and transmit secure keys. The technology provides unparalleled security as these photons can’t be intercepted, copied, or measured without altering their quantum states.

“The results from this pioneering experiment from a collaborative research initiative between scientists from Stellenbosch University and the University of Science and Technology of China were published in Nature today,” Stellenbosch University said.

Ideal environmental conditions in Stellenbosch, namely clear skies and low humidity, enabled the local ground station to achieve a key generation rate of 1.07 million secure bits during a single satellite pass.

China is at the leading edge of quantum communication technology, under the guidance of quantum physicist Professor Jian-Wei Pan.

The nation’s infrastructure includes a 2,000km terrestrial fibre-based quantum network, connecting 32 trusted nodes across major cities from Beijing to Shanghai.

Professor Juan Yin, who was instrumental in developing China’s first quantum satellite, Micius, led the Chinese research in its collaboration with South African scientists.

The South African research team, based at Stellenbosch University’s Department of Physics, was led by Dr Yaseera Ismail. Ismail was the lead experimentalist responsible for establishing the link.

“International and national collaborations are essential to drive cutting-edge research and push scientific boundaries,” said Ismail.

“Implementing the first quantum satellite link in the Southern Hemisphere is an outstanding achievement for South Africa, demonstrating the significant potential to develop a thriving quantum ecosystem.”

Francesco Petruccione, Professor of Quantum Computing in the School of Data Science and Computational Thinking, and Director of the National Institute for Theoretical and Computational Sciences (NITheCS) at Stellenbosch University commented on the achievement.

Petruccioni pioneered quantum communication in South Africa, developing one of the world’s first fibre-optic quantum communication networks in Durban.

“This successful demonstration of quantum satellite technology firmly positions South Africa as a significant player in the rapidly evolving global quantum technology ecosystem,” he said.

“Collaborations such as this accelerate scientific breakthroughs, build local expertise, and enable translating advanced quantum research into tangible technological solutions.”

The research paper, entitled “Microsatellite-based real-time quantum key distribution”, was published in Nature and is available there.