500-km quantum-based network for digitally secure communications successfully demonstrated

A Bengaluru-based startup, in collaboration with the Indian Army, has successfully demonstrated India’s first extensive Quantum Key Distribution (QKD) network, spanning over 500 km.

This involved a network deployed over the existing optical fibre infrastructure, marking a significant milestone in developing secure digital communications and enhancing cyber security.

A QKD network, according to experts, uses the principles of quantum mechanics, a branch of physics dealing with the behaviour of matter and energy at the smallest scale, to securely share cryptographic keys between two parties, enabling them to encrypt and decrypt communication streams with high security.

QKD relies on the fact that any attempt by an eavesdropper to intercept the quantum key will disturb the signal, which is then detected by the legitimate users, making it provably secure against both classical and future quantum attacks QKD is more secure that conventional encryption methods based on mathematical complexity.

The Indian Army’s Southern Command contributed significantly in the capability demonstration. The test-bed optical fibre network, to enable this QKD trial, was specially planned and engineered by the Command’s Signals elements.

A team from the Corps of Signals enabled selective access to their fibre network in the Rajasthan sector. This network included multiple nodes, of which two served as trusted nodes spread along the route to enable end-to-end quantum key exchange across an effective distance of more than 500 km.

The company involved in the project, QNu Labs Private Limited, is one of the eight startups supported under National Quantum Mission (NQM) by Department of Science and Technology, the Ministry of Science and Technology said on Wednesday.

This demonstration positions India as a key player in the second quantum revolution, opening new horizons for secure digital communication and advanced cybersecurity, and is a fillip towards self-reliance in emerging technologies and secure digital infrastructure.

The project funded through the I-Hub Quantum Technology Foundation, a Technology Innovation Hub under the National Mission on Interdisciplinary Cyber-Physical Systems hosted by the Indian Institutes of Science Education and Research, Pune.

This achievement represents a significant milestone in the advancement of quantum-secure communications within India and exemplifies the synergy of technology, research, industry and defence ecosystem (STRIDE) in fostering collaboration across key sectors to strengthen technological capabilities, the ministry said.