NEW DELHI: In a giant leap for India’s defence and cybersecurity capabilities, scientists from the Defence Research and Development Organisation (DRDO) and IIT Delhi have successfully demonstrated quantum entanglement-based secure communication over a distance of more than one kilometre. The experimental breakthrough was conducted on the IIT Delhi campus using a free-space optical link, which allows secure data transmission without using physical cables.
This experiment marks India’s formal entry into the global race for developing next-generation quantum communication technologies. Using entangled photons — pairs of light particles that remain connected even when separated — the system achieved a secure key rate of 240 bits per second with a quantum bit error rate (QBER) below 7%, indicating high transmission accuracy and security.
Quantum entanglement makes communication nearly impossible to hack. If any outsider tries to intercept the communication, the quantum state is disturbed, immediately revealing an intrusion attempt. This feature makes quantum communication systems unbreakable, especially vital in defence, finance, and national infrastructure.
This cutting-edge demonstration was carried out under the DRDO-funded project “Design and development of photonic technologies for free space QKD”. The experiment was led by Prof. Bhaskar Kanseri’s team at IIT Delhi and witnessed by top DRDO officials, including the DG (MED, COS & CS), Director SAG, Director DFTM, and Dean (R&D) of IIT Delhi.
Speaking on the occasion, Defence Minister Rajnath Singh congratulated the DRDO-IIT Delhi team, saying that India has now “entered into a new quantum era of secure communication” that will play a vital role in future warfare scenarios and cyber defence systems.
This isn’t the team’s first quantum success. In 2022, DRDO and IIT Delhi built India’s first intercity quantum link between Vindhyachal and Prayagraj, using underground optical fibre. In 2024, they distributed entanglement-based quantum keys over a 100-kilometre spool of telecom-grade optical fibre — showing that India is consistently advancing in this frontier.
The technology was developed at one of DRDO’s 15 Centres of Excellence (DIA-CoEs) located in top academic institutes like IITs and IISc. These Centres are designed to encourage collaborative R&D between the military and academia, focusing on futuristic tech such as AI, autonomous systems, and quantum computing.
According to experts, free-space Quantum Key Distribution (QKD) like this offers major advantages. It eliminates the need for laying cables, making it ideal for difficult terrain, war zones, or rapidly changing environments. Plus, even if the hardware used is flawed or compromised, the entanglement-based method ensures that security isn’t broken — which isn’t possible in conventional encryption.
The long-term goal is to integrate such systems into a future “Quantum Internet” — a network where sensitive information can be transmitted globally with absolute security. This step will make India one of the few nations ready to defend itself in a world where quantum computing could soon break today’s digital security systems.
Senior officials including Dr. Samir V Kamat, Chairman of DRDO, and Prof. Rangan Banerjee, Director of IIT Delhi, have also congratulated the team, calling this a major step forward in securing India’s digital and strategic communication infrastructure.
