India’s Ministry of Defence announced a major milestone in quantum communications: the successful demonstration of quantum entanglement-based secure communication over a one-kilometer free-space optical link. The experiment was conducted on the IIT Delhi campus as part of a project led by Professor Bhaskar Kanseri and supported by the Defence Research and Development Organisation (DRDO) under its Directorate of Futuristic Technology Management.
The test achieved a secure key rate of approximately 240 bits per second with a quantum bit error rate below 7%. This marks a significant step toward practical deployment of entanglement-assisted quantum key distribution (QKD), a method that offers stronger security guarantees than prepare-and-measure QKD by detecting any attempts at eavesdropping through quantum state disturbance. The demonstration supports India’s broader goals to develop robust quantum cyber defense capabilities, quantum networks, and future quantum internet infrastructure.
This work builds on previous efforts by the same team, including India’s first intercity quantum link over underground fiber in 2022 and a 100 km quantum key distribution via telecom-grade optical fiber in 2024. Unlike fiber-based links, the new free-space system can be deployed in environments where laying fiber is impractical or cost-prohibitive, paving the way for secure battlefield, airborne, and satellite-based communications.
The research was carried out under the DRDO-Industry-Academia Centre of Excellence (DIA-CoE) program, which funds cutting-edge quantum and defense research at top Indian institutions such as IITs and IISc. In a statement, Raksha Mantri Rajnath Singh called the demonstration a “game changer in future warfare,” highlighting India’s emergence into a new quantum era of secure communications.
Read the official release from India’s Press Information Bureau here.
June 20, 2025
