India has demonstrated its first free-space Quantum Key Distribution (QKD) link over a distance of 5.56 km, marking a significant step towards developing secure communication networks capable of withstanding emerging quantum-era security threats.
The demonstration was carried out by QNu Labs in collaboration with the Bhaskaracharya National Institute for Space Applications and Geo-informatics (BISAG-N) and IIT Gandhinagar.
The field trial was conducted on the night of September 27–28, establishing a secure quantum communication channel between BISAG-N and IIT Gandhinagar.
Using QNu Labs’ Pointing, Acquisition and Tracking (PAT) system, the trial achieved a stable Quantum Bit Error Rate (QBER) below 5 per cent and generated secure keys at a rate of 230–260 bits per second (bps).
The generated keys were integrated with BISAG-N’s post-quantum cryptography-enabled Vedic Kavach platform, allowing successful end-to-end encryption and decryption of test messages.
Combining Two Layers of Quantum Security
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 BISAG-N’s Vedic Kavach provided software-based post-quantum cryptography along with quantum random number generation.
According to the participating institutions, the integrated architecture is designed to provide resilience 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 represented a significant step towards practical quantum-resilient communication systems.
Sunil Gupta, Co-founder and CEO, QNu Labs, said the successful 5.56-km demonstration could pave the way for longer-distance quantum-secure networks and eventually 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. He also highlighted the integration of academic research, indigenous technology and real-world experimentation to address emerging secure communication requirements.
Foundation for Quantum-Secure Networks
Quantum Key Distribution enables the secure exchange of cryptographic keys using the principles of quantum mechanics. The latest demonstration provides a field-tested foundation for expanding India’s capabilities in secure communication infrastructure.
The initiative is expected to support the development of technologies aimed at strengthening communications against security threats that could emerge with advances in quantum computing.
About the participating institutions
BISAG-N is an autonomous scientific society under the Ministry of Electronics and Information Technology (MeitY). It works in areas including space technology applications, satellite communication and geo-informatics, while supporting technology-driven governance.
IIT Gandhinagar, established in 2008, is an institution focused on engineering, science, technology, humanities and social sciences. It promotes interdisciplinary research, innovative education and solutions to real-world challenges.
QNu Labs, founded in 2016, develops quantum-secure digital infrastructure and provides quantum security products and solutions, including technologies for secure communications.
