On June 16, 2025, India hit a historic milestone in quantum technology when the Defence
Research and Development Organisation (DRDO) and the Indian Institute of Technology (IIT)
Delhi showcased successful quantum entanglement-based free-space quantum secure
communication beyond a kilometre. This successful event, pulled through the DRDO-Industry
Academia Centre of Excellence (DIA-CoE) at IIT Delhi, is an important milestone in the field
of quantum cryptography, heading to an eventual point of quantum cybersecurity, quantum
networks, and the future quantum internet.
A New Era of Secure Communication
The demonstration – executed through a free-space optical link on the IIT Delhi campus –
attained a secure key rate of around 240 bits per second with a quantum bit error rate less than
7%. Under the direction of Professor Bhaskar Kanseri’s research group, the experiment
illustrated quantum key distribution (QKD), with quantum entanglement – two particles are
naturally linked, so any change in one will instantly change the other, no matter how far apart
in space and time. This property provides the assurance that if an unauthorised user were to
intercept or measure the entangled photons (and thus gain knowledge of any mutual entangled
states), the quantum state of the photons would be disturbed (or disrupted). The authorised
users or channels would be alerted, and the classical information would be immune to man-in
the-middle attacks.
While encryption methods today still rely on complex mathematical algorithms, even though
we feel reasonably assured the algorithms cannot be deciphered now, through entanglement
based QKD we could issue encryption that could not be broken. This is a potential game
changer for sensitive data in critical and strategic areas such as defence, finance and
telecommunications, where cybersecurity is the most important.
A Collaborative Triumph
The demonstration was attended by several important dignitaries, including: Director General,
Medical, Combat and Cyber Security, DRDO; Directors, Scientific Analysis Group (SAG),
India; Directors, Directorate of Futuristic Technology Management (DFTM); Dean of
Research and Development, IIT Delhi; and several scientists from DRDO. The project was
titled “Design and Development of Photonic Technologies for Free-Space QKD” and was
approved by the DFTM under DRDO’s deep-tech initiatives, reflecting DRDO’s intent to
support disruptive technologies in defence technology.
This is an excellent follow-up from the team’s previous accomplishments. In 2024, DRDO and
IIT Delhi successfully delivered quantum keys based on entanglement over 100 km of telecom
grade optical fibre, thereby showing that quantum communication can work on a variety of
platforms (i.e., fibre or free-space). The free-space QKD demo now allows the QKD
technology to be deployed beyond the constraint of physical cables/hardwiring, leveraging the
advantages of optical communications or laser beams and making it applicable across multiple
operational domains.
Strategic Implications and Future Prospects
Raksha Mantri Shri Rajnath Singh hailed DRDO and the team for a breakthrough he dubbed a
“game changer for future warfare and the emancipation of national cyber security”. This
technology will allow systems to be connected with communication capabilities that are
impossible to interfere with or hack, even under the most sophisticated challenges. The
perspectives we detailed will also complement India’s national vision for quantum technology
and create a foundation from which quantum communication of this kind will be developed.
Furthermore, the anticipation cosmology will allow for secure, encrypted communication to be
developed and utilised in broader contexts than defence, banking, telecommunications, and
others will become practical applications. This breakthrough will create global impetus that
will galvanise the ecosystem of innovation across many use cases, not only in defence but in
enabling environments that will develop secure revolutionary and advanced technological
ecosystems.
DRDO’s Vision for Quantum Innovation
The attainment of this milestone is part of DRDO’s larger plan to grow indigenous quantum
capabilities. The newly launched Quantum Technology Research Centre (QTRC) at Metcalfe
House in Delhi, in collaboration with the DRDO’s Solid State Physics Laboratory (SSPL), will
provide state-of-the-art experimental facilities for research in quantum sensing, secure
communications, and post-quantum cryptography. DRDO’s partnership with academic
institutions such as IIT Delhi, through 15 Centres of Excellence, demonstrates the readiness to
innovate using industry-academia partnerships.
Secretary of Defence R&D and DRDO Chairman Dr Samir V. Kamat and IIT Delhi Director
Prof. Rangan Banerjee recognised the team for their efforts and for working collaboratively
within a unique ecosystem to deliver this demonstration of capability. The demonstration of
this success shows how collaborations can fulfil demand for capabilities expected to be
delivered to national security and technological sovereignty.
Looking Ahead
India’s efforts to develop free-space communication based on quantum entanglement is an
important step forward to a safer and more robust digital future. With the continued investment
in quantum technologies through the National Quantum Mission and initiatives with top
institutions, India sits in a position to become a formidable player in the quantum race. The
successful demonstration by the DRDO and IIT Delhi shows promise for India’s strategic
defence capacity, and its potential for substantial improvements in cybersecurity and
communication networks – a new quantum era for Bharat.