India demonstrates its first 5.56 km free-space quantum key link, from BISAG-N to IIT Gandhinagar
India has demonstrated its first free-space quantum key distribution link, 5.56 km between BISAG-N and IIT Gandhinagar, PIB said on 3 October 2026. QNu Labs’ Armos system held the error rate under 5 percent and produced keys at 230–260 bits per second, which BISAG-N’s Vedic Kavach platform used to encrypt and decrypt test messages.
On 3 October 2026, India has demonstrated its first free-space Quantum Key Distribution link, over 5.56 kilometres, between the Bhaskaracharya National Institute for Space Applications and Geo-informatics and IIT Gandhinagar.
QNu Labs ran the quantum hardware.
BISAG-N put the keys into its own post-quantum platform and decrypted test messages.
The distance is short by fibre standards.
The medium is the point.
The keys crossed open air, not a cable.
What was shown
Quantum key distribution does not send the secret itself as a quantum message.
It sends the material from which both ends build the same encryption key, in a form that an eavesdropper disturbs.
If someone taps the optical path, the error rate moves, and the key is discarded.
That is the property this trial was exercising outdoors.
The link ran from BISAG-N to IIT Gandhinagar.
QNu Labs used its Armos QKD device and a Pointing, Acquisition and Tracking system to hold the beam on the far terminal.
The trial held a quantum bit error rate below 5 percent and produced secure keys at 230 to 260 bits per second.
Those keys were handed to Vedic Kavach, BISAG-N’s software platform for post-quantum cryptography and quantum random number generation.
Test messages were encrypted and decrypted end to end.
Two layers were stacked on purpose.
Armos supplies a key whose theft would show up on the optical path.
Vedic Kavach is built for a later threat, a computer that can break today’s public-key maths.
The release says the combined design still protects traffic if the quantum channel drops for a while, because the software layer does not depend on the beam staying up.
Reporting of the MeitY account places the field trial on the night of 27, 28 September 2026.
Free-space optics are usually run at night because daylight swamps the detector.
Why free space is the achievement
India has already shown QKD on fibre.
QNu Labs, a startup backed under the National Quantum Mission, has demonstrated fibre QKD networks measured in hundreds of kilometres, including a deployment of more than 500 kilometres announced by the Department of Science and Technology.
That work and this work are not the same record.
Fibre follows a duct.
Free space has to find the other rooftop, hold aim through air, and live with weather and background light.
A satellite quantum link is free space with the far end in orbit.
A 5.56 kilometre city path does not make a satellite system.
It is the first outdoor step the government is claiming toward one.
Sunil Gupta, co-founder and chief executive of QNu Labs, said the 5.56 kilometre result opens the way to longer quantum-secure networks and to satellite-based quantum communication.
Dr Vinay Thakur, Director General of BISAG-N, called the joining of Vedic Kavach with the QKD link a step toward practical quantum-resilient systems.
Commodore Manish Tripathi (retired), in charge of ISTF at IIT Gandhinagar, said the campus gave the trial a real field, not a bench, and that the value was academia, an Indian product, and an outdoor test in one place.
Who built it
QNu Labs was founded in 2016.
The company describes itself as building sovereign quantum-secure products, and it is one of the startups supported under the National Quantum Mission.
BISAG-N is an autonomous scientific society under the Ministry of Electronics and Information Technology, working in space applications, satellite communication, and geo-informatics for government.
IIT Gandhinagar supplied the far end and the field conditions.
The rate of 230 to 260 bits per second is enough to refresh keys for a high-value channel.
It is not a data pipe.
The quantum link carries key material.
The messages still travel on an ordinary encrypted channel, which is what the Vedic Kavach test did.
A national quantum network would need many such hops, trusted nodes or satellites, and daylight and monsoon performance this one night does not show.
The release does not claim those.
It claims a first free-space link at this distance, with a measured error rate, a measured key rate, and a working handshake into a government post-quantum platform.
Written by: Quantum Research Unit, Ministry of Cyber Affairs