QNu Labs, in partnership with BISAG-N and IIT Gandhinagar, conducted field tests of a 5.56 km free-space quantum key distribution (QKD) link. The experiment took place on the night of September 27–28 in Gujarat, utilizing the Pointing, Acquisition and Tracking (PAT) system for optical alignment.
During the test, the quantum bit error rate (QBER) remained below 5%, with a secure key generation rate of 230–260 bits per second. According to the Indian Ministry of Electronics and IT, this marks the first demonstration of a free-space QKD channel of this scale in the country.
The architecture integrates hardware-based QKD via the Armos device with a software layer using Vedic Kavach, which supports post-quantum cryptography (PQC) and quantum random number generation. The system successfully encrypted, transmitted, and decrypted test messages using 256-bit keys.
The project aims to serve as a stepping stone for developing multi-kilometer networks and increasing the number of nodes. Participants intend to leverage these results to advance toward satellite-based quantum communication in the future.
