Gandhinagar: India has demonstrated its first free-space Quantum Key Distribution (QKD) link over a distance of 5.56 km, with a field trial successfully establishing a secure quantum communication channel between the Bhaskaracharya National Institute for Space Applications and Geo-informatics (BISAG-N) and IIT Gandhinagar.
The trial was conducted on the night of September 27-28 by QNu Labs in collaboration with BISAG-N and IIT Gandhinagar.
It used QNu Labs’ Pointing, Acquisition and Tracking system to maintain the free-space optical link and achieved a stable Quantum Bit Error Rate (QBER) below five per cent.
The system generated secure keys at a rate of 230-260 bits per second.
These keys were subsequently integrated with BISAG-N’s post-quantum cryptography-enabled Vedic Kavach platform, allowing successful end-to-end encryption and decryption of test messages.
The demonstration brought together two complementary approaches to quantum security.
QNu Labs’ hardware-based Armos QKD device was used over free-space optical channels, while Vedic Kavach provided software-based post-quantum cryptography along with quantum random number generation.
The integrated architecture is designed to remain resilient even when the physical quantum communication channel is temporarily unavailable.
Dr Vinay Thakur, Director General, BISAG-N, said the integration of Vedic Kavach with QNu Labs’ QKD technology marked “a significant step towards practical quantum-resilient communication systems”.
Sunil Gupta, Co-founder and CEO of QNu Labs, said: “The successful 5.56-km demonstration paved the way for longer-distance quantum-secure networks and satellite-based quantum communication.”
Cmde Manish Tripathi (Retd), In-charge, ISTF, IIT Gandhinagar, said the demonstration provided a valuable field environment for advancing practical quantum communication technologies.
“It showed how academia, indigenous technology and real-world experimentation could be integrated to address emerging secure communication requirements,” he added.
Free-space QKD transmits quantum signals through optical channels in open air rather than through fibre, making it a potential option for communication links where deploying fibre is challenging.
The technology also has potential applications in longer-distance and satellite-based quantum communication.
The trial provides a foundation for advancing India’s secure communication infrastructure and strengthening resilience against emerging quantum-era security threats.
BISAG-N, an autonomous scientific society under the Ministry of Electronics and Information Technology, works in areas including space technology applications, satellite communication and geo-informatics, while IIT Gandhinagar, established in 2008, focuses on interdisciplinary research and education across engineering, science, technology, humanities and social sciences.
QNu Labs, founded in 2016, develops quantum-secure digital infrastructure and describes itself as a pioneer in sovereign quantum security products and solutions.
(IANS)
