India Demonstrates Quantum-Secure Communication Over 1km

The Defence Research and Development Organisation (DRDO) and IIT Delhi have successfully demonstrated free-space quantum secure communication using quantum entanglement over a distance exceeding one kilometre. The experiment, conducted on the IIT Delhi campus, marks a key milestone in India’s quantum communication capabilities.

The demonstration was part of the DRDO-funded project titled ‘Design and development of photonic technologies for free space QKD (quantum key distribution)’. It was carried out by IIT Delhi professor Bhaskar Kanseri’s research group under the DRDO-Industry-Academia Centre of Excellence (DIA-CoE) at the university. 

The experiment attained a secure key rate of nearly 240 bits per second with a quantum bit error rate of less than 7%. This technology supports secure QKD without using fibre-optic cables.

The achievement is expected to contribute to developments in quantum cybersecurity, quantum networks, and the future quantum internet. India’s defence minister Rajnath Singh called the event a turning point, stating that India has entered a new quantum era of secure communication, which will be a game changer in future warfare. 

This work is part of a larger national initiative involving 15 DRDO-funded centres of excellence across IITs, IISc, and other universities to drive forward the country’s defence technologies.

This experimental success enhances India’s ongoing efforts in dual-use technologies for both civil and defence sectors. It offers improved security over traditional methods, even in compromised or imperfect systems. Unlike classical methods, entanglement-based QKD detects any interception attempts, ensuring higher security levels.

Key DRDO officials, including the DG (MED, COS & CS), director SAG, director DFTM, and IIT Delhi’s dean (R&D), oversaw the project. India has previously achieved milestones in the field, including a 100 km entanglement-based key distribution using telecom-grade optical fibre and an intercity quantum communication link between Vindhyachal and Prayagraj in 2022.

Additionally, in December last year, a team of professors at the Raman Research Institute (RRI), led by Urbasi Sinha, researched estimating the signal strength, atmospheric losses, and alignment for secure satellite-to-ground quantum communication. 

Sinha told AIM in an interview that after analysing existing open-source data available on three of India’s most sophisticated observatory sites, the team found that the Indian Astronomical Observatory (IAO) in Hanle (Ladakh) is the prime candidate for this revolutionary technology.