India has reached a major milestone in quantum cyber defense, successfully demonstrating quantum entanglement-based free-space secure communication over a distance exceeding one kilometer. The experiment, carried out by IIT Delhi’s DRDO-Industry-Academia Centre of Excellence, achieved a secure key rate of 240 bits per second with a quantum bit error rate below 7%, marking a significant leap toward the realization of unbreakable encryption for critical communications.
The demonstration utilized a free-space optical link on IIT Delhi’s campus under a project funded by the Defence Research and Development Organisation’s Directorate of Futuristic Technology Management. The team, led by Professor Bhaskar Kanseri, achieved secure Quantum Key Distribution (QKD) by leveraging entangled photon pairs—a method that guarantees data integrity even if system devices are compromised. The presence of an eavesdropper can be detected through the inherent disturbance entanglement introduces when observed, reinforcing the method’s strategic value in defense and national security.
Defence Minister Rajnath Singh congratulated DRDO and IIT Delhi, calling the achievement a “game changer in future warfare” that propels India into a new era of quantum communication. DRDO Chairman Samir V Kamat and IIT Delhi Director Rangan Banerjee also praised the research team’s contribution to cutting-edge defense innovation.
The trial is the latest in a series of quantum research milestones by DRDO and IIT Delhi. In 2022, the same collaboration demonstrated India’s first intercity quantum communication link between Vindhyachal and Prayagraj using underground optical fiber. In 2024, they successfully distributed quantum keys via entanglement across a 100-kilometer spool of telecom-grade fiber.
The breakthrough is part of India’s strategy to develop quantum-secure networks without relying on fiber infrastructure, critical for complex terrains and urban settings. The effort underscores DRDO’s push to develop next-generation dual-use technologies across 15 academic-led Centres of Excellence nationwide. With secure quantum communication now a reality, India is one step closer to building a national quantum internet backbone for defense, finance, and space communications.
