India's First 5.56 km Free-Space Quantum Key Distribution Link Demonstrated
QNu Labs, in collaboration with Bhaskaracharya National Institute for Space Applications and Geo-informatics (BISAG-N) and IIT Gandhinagar, has successfully demonstrated India's first free-space Quantum Key Distribution (QKD) link at a scale of 5.56 km. The field trial was conducted on the night of September 27-28, 2026, establishing a secure quantum communication channel between BISAG-N and IIT Gandhinagar.
The technical achievement involved using QNu Labs' Pointing, Acquisition and Tracking system, which achieved a stable Quantum Bit Error Rate below 5% and generated secure keys at a rate of 230-260 bits per second. These quantum keys were successfully integrated with BISAG-N's post-quantum cryptography enabled Vedic Kavach platform, enabling end-to-end encryption and decryption of test messages.
The demonstration combined two complementary layers of quantum security: QNu Labs' hardware-based QKD device Armos over free-space optical channels and BISAG-N's Vedic Kavach software-based post-quantum cryptography with quantum random number generation. This integrated architecture ensures resilience even if the physical quantum channel becomes temporarily unavailable.
Dr. Vinay Thakur, Director General of BISAG-N, stated that the integration of Vedic Kavach with QNu Labs' QKD technology marks a significant step towards practical quantum-resilient communication systems. Sunil Gupta, Co-founder and CEO of QNu Labs, emphasized that the successful 5.56 km demonstration paves the way for longer-distance quantum-secure networks and satellite-based quantum communication. Cmde Manish Tripathi (Retd.), In-charge of ISTF at IIT Gandhinagar, noted that the demonstration provides a valuable field environment for advancing practical quantum communication technologies and showcases how academia, indigenous technology, and real-world experimentation can be integrated to meet emerging secure communication requirements.
The trial provides a foundation for advancing India's capabilities in secure communication infrastructure, strengthening resilience against emerging quantum-era security threats. The participating institutions include BISAG-N, an autonomous scientific society under MeitY working in space technology applications and satellite communication; IIT Gandhinagar, a leading institution focused on engineering, science, and technology; and QNu Labs, India's pioneer in quantum-secure digital infrastructure founded in 2016.