New Delhi, June 2025 — Marking a significant milestone in the field of quantum technologies, the Defence Research and Development Organisation (DRDO) in collaboration with the Indian Institute of Technology (IIT) Delhi has successfully demonstrated quantum entanglement-based secure communication over a free-space distance exceeding one kilometre.
The demonstration, conducted by the DRDO-Industry-Academia Centre of Excellence (DIA-CoE) at IIT Delhi, achieved a secure key rate of approximately 240 bits per second with a quantum bit error rate (QBER) of less than 7%. The success opens new avenues for real-time applications in quantum cyber security, including long-distance Quantum Key Distribution (QKD), quantum networks, and the envisioned quantum internet.
This achievement was made under the project titled “Design and development of photonic technologies for free space QKD,” sanctioned by the Directorate of Futuristic Technology Management (DFTM), DRDO. The experimental demonstration was led by Prof. Bhaskar Kanseri’s research group and was witnessed by key dignitaries including the DRDO DG (MED, COS & CS), Director SAG, Director DFTM, Dean (R&D) IIT Delhi, and other senior DRDO scientists.
Quantum entanglement-based QKD presents significant advantages over traditional prepare-and-measure methods, offering enhanced security even when devices are compromised. The principle of quantum entanglement ensures that any interception attempt disturbs the quantum state, alerting users to potential eavesdropping. Moreover, free-space QKD eliminates the need for costly and logistically challenging fiber-optic installations, particularly in difficult terrains and urban settings.
This breakthrough follows a series of DRDO-led quantum communication advancements. In 2022, India’s first intercity quantum link was demonstrated between Vindhyachal and Prayagraj using underground dark optical fiber. In 2024, Prof. Kanseri’s team achieved entanglement-based key distribution over 100 km of telecom-grade optical fiber.
These initiatives fall under DRDO’s wider push for indigenous development of next-generation defence technologies through DIA-CoEs. Currently, 15 such Centres of Excellence operate in collaboration with top institutions like IITs, IISc, and other premier universities.
Raksha Mantri Shri Rajnath Singh hailed the development as a “game-changer in future warfare,” congratulating DRDO and IIT Delhi for ushering India into a new era of secure quantum communication. Secretary, Department of Defence R&D and DRDO Chairman Dr. Samir V Kamat, along with IIT Delhi Director Prof. Rangan Banerjee, also lauded the team for this landmark achievement.
As India continues its stride into the quantum frontier, this demonstration marks a crucial step toward building secure, resilient communication systems critical for national security and technological sovereignty.
