India Reports a 5.56 km Free-Space Quantum Key Link - A Field Trial, Not Yet a Network
- QNu Labs, BISAG-N and IIT Gandhinagar report a 5.56 km free-space QKD link, trialled on the night of 27-28 September 2026 and announced on 3 October.
- Reported performance is a quantum bit error rate below 5% and a secure key rate of 230-260 bits per second.
- The link used QNu Labs' Armos QKD device with its pointing, acquisition and tracking system and BISAG-N's Vedic Kavach post-quantum platform.
- It is a short, night-time, fixed-site trial, and earlier shorter Indian free-space quantum demonstrations exist, so the first-of-its-kind framing is limited.
- Figures come from a government statement carried by several agencies and are not independently verified.
- QNu Labs, BISAG-N and IIT Gandhinagar report a 5.56 km free-space QKD link, trialled on the night of 27-28 September 2026 and announced on 3 October.
- Reported performance is a quantum bit error rate below 5% and a secure key rate of 230-260 bits per second.
- The link used QNu Labs' Armos QKD device with its pointing, acquisition and tracking system and BISAG-N's Vedic Kavach post-quantum platform.
- It is a short, night-time, fixed-site trial, and earlier shorter Indian free-space quantum demonstrations exist, so the first-of-its-kind framing is limited.
- Figures come from a government statement carried by several agencies and are not independently verified.
- Swarajya (3 Oct 2026): https://swarajyamag.com/tech/india-achieves-first-556-km-free-space-qkd-link-in-major-quantum-secure-communication-trial
- Asianet Newsable, ANI feed (3 Oct 2026): https://newsable.asianetnews.com/business/india-successfully-tests-free-space-quantum-key-distribution-over-5-56-km-articleshow-qoqdii6
- The Hawk, IANS feed (3 Oct 2026): https://www.thehawk.in/news/economy-and-business/india-showcases-its-first-556-km-freespace-quantum-communication-link
- The Quantum Insider (20 Jun 2025), earlier Indian free-space work: https://thequantuminsider.com/2025/06/20/india-takes-significant-step-in-quantum-communication-with-one-kilometer-entanglement-test/
The development
On 3 October 2026, QNu Labs, the Bhaskaracharya National Institute for Space Applications and Geo-informatics (BISAG-N) and IIT Gandhinagar announced a free-space quantum key distribution trial over 5.56 km between BISAG-N and IIT Gandhinagar in Gujarat. The trial ran at night on 27-28 September. The reported quantum bit error rate was below 5% and the secure key generation rate was 230-260 bits per second. The link combined QNu Labs' Armos hardware-based QKD device and its pointing, acquisition and tracking system with BISAG-N's Vedic Kavach platform, which adds post-quantum cryptography and quantum random number generation. The announcement is described as India's first free-space QKD link.
What the numbers mean
A free-space link sends the quantum signal through the atmosphere rather than a fibre, so the hard engineering is keeping a narrow beam aimed and stable between two fixed points, which is what the pointing, acquisition and tracking system does. An error rate under 5% shows the link was usable for key generation, and 230-260 bits per second is enough for refreshing symmetric keys, not for bulk data. A night-time, 5.56 km trial between two fixed sites is a proof of operation, not a deployed service, and it says nothing yet about daytime, weather or mobile platforms.
Where it sits in the stack
Free-space links matter because they are the building block for links where laying fibre is impractical, and for the satellite-to-ground quantum links the National Quantum Mission targets. The trial pairs an Indian QKD hardware maker with a state geo-informatics institute and an IIT, which is the kind of domestic integration the mission is meant to encourage. The reporting does not say where the sources, detectors or optics inside the Armos device are made, so the supply chain below the system level is not established.
The first-of-its-kind claim should be read carefully. Earlier Indian free-space quantum-secure communication demonstrations, including DRDO and IIT Delhi work over shorter distances, have been reported, so this is better read as a longer link under this team than as the first of any kind.
On sourcing: coverage of the announcement from several outlets traces back to one government statement carried by news agencies, so the performance figures are as stated by the participants and have not been independently verified.
What to watch
- Daytime, longer-range and weather-varied trials of the same link.
- Disclosure of where the detectors, sources and optics are made.
- Integration with a fibre or satellite segment under the National Quantum Mission.
- A first customer or pilot for government or defence networks.
Track the systems we watch
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