India’s first 5.56 km free-space quantum key distribution link demonstrated in Gandhinagar
Key facts
- QNu Labs, BISAG-N and IIT Gandhinagar demonstrated India's first free-space QKD link at a 5.56 km scale.
- The field trial ran on the night of 27-28 September 2026, between BISAG-N and IIT Gandhinagar.
- It kept the quantum bit error rate below 5% and generated secure keys at 230-260 bits per second.
- The keys were paired with BISAG-N's Vedic Kavach post-quantum cryptography platform.
Why it matters
[First] Quantum Key Distribution (QKD) shares encryption keys using single particles of light. Any attempt to eavesdrop disturbs them and shows up as errors. Free-space QKD needs no optical fibre, so it can work through open air. The team says this paves the way for longer links and satellite-based quantum communication.
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