India demonstrated its first 5.56-kilometre free-space quantum key distribution link on 3 October 2026, establishing a secure atmospheric communication channel without relying on fibre-optic infrastructure. Conducted by QNu Labs, BISAG-N, and IIT Gandhinagar, the trial achieved a stable quantum bit error rate below 5 per cent and generated secure keys at 230–260 bps.
This atmospheric milestone bypasses the physical vulnerability of terrestrial fibre networks. The system resists interception. The trial integrated QNu Labs' Armos hardware-based device with BISAG-N's Vedic Kavach post-quantum cryptography software, enabling successful end-to-end encryption and decryption of test messages. This dual-layer architecture ensures communication resilience even during physical channel disruptions. The breakthrough builds on an earlier demonstration of a one-kilometre link achieved by DRDO and IIT Delhi in June 2025. By scaling free-space quantum key distribution, India advances its strategic capabilities in intercept-proof military and governmental communications, paving the way for satellite-based quantum networks.