India Transmits Quantum Keys Across 5.56 km of Open Air

QNu Labs, BISAG-N and IIT Gandhinagar demonstrated India's first free-space QKD link at the 5 km scale, transmitting single photons over 5.56 km between two campuses in Gandhinagar. The trial achieved a secure key rate of 230–260 bps with a QBER below 5%, validating the atmospheric segment needed for future satellite QKD.

• 5.56 km link is more than 5x India's previous free-space QKD record
• Secure key rate of 230–260 bps with QBER below 5%
• Used DPS-Decoy protocol at 1550 nm telecom wavelength
• Keys fed into BISAG-N's Vedic Kavach platform via ETSI GS QKD 014 API