India Advances Toward Unbreakable Communication with Quantum Encryption Milestone

On June 16, 2025, India achieved a critical milestone in quantum communication through a collaboration between the Defence Research and Development Organisation (DRDO) and the Indian Institute of Technology (IIT) Delhi. The joint team successfully demonstrated secure communication using quantum entanglement over a free-space distance exceeding one kilometer. Conducted at the DRDO-Industry-Academia Centre of Excellence (DIA-CoE) on IIT Delhi’s campus, this experiment leveraged entangled photons to exchange encryption keys in open air, achieving a secure key generation rate of about 240 bits per second while maintaining a quantum bit error rate (QBER) below 7%. This development moves India closer to creating unbreakable communication systems and aligns it with global leaders in quantum cybersecurity.

Experiment Details and Scientific Relevance

This demonstration is part of a DRDO-sponsored initiative titled “Design and Development of Photonic Technologies for Free Space Quantum Key Distribution (QKD),” led by Professor Bhaskar Kanseri’s research team at IIT Delhi. The team utilized entangled photons to implement Quantum Key Distribution, a method that guarantees security by relying on the fundamental laws of quantum physics.

In the setup, entangled photon pairs were generated, with each pair split between two locations: one sent to a transmitting station and the other to the receiver through a free-space optical path. The entangled nature of these photons ensures that any attempt to intercept the key introduces detectable disturbances, immediately alerting the legitimate users. This is a significant departure from conventional QKD systems, which typically rely on single photons and assume ideal conditions. The success of this approach despite environmental disturbances such as air turbulence demonstrates the robustness and practicality of entanglement-based QKD.

Senior officials from DRDO and IIT Delhi were present at the demonstration, highlighting its importance at both scientific and strategic levels.

The Larger Context of India’s Quantum Efforts

This achievement builds upon previous milestones in India’s quantum communication journey. In 2022, the same IIT Delhi team collaborated with DRDO to set up India’s first intercity quantum communication link between Vindhyachal and Prayagraj using underground optical fibers. Later, in 2024, they accomplished quantum entanglement-based QKD over 100 kilometers of telecom-grade fiber. However, the latest advancement, which removes the reliance on costly fiber optics, represents a leap forward in deploying scalable, cost-efficient quantum networks suitable for both rural and urban environments.

These efforts are supported by India’s National Quantum Mission (NQM), a ₹6,003 crore ($720 million) initiative launched in 2023 to promote research and development in quantum computing, communication, materials, and sensing technologies by 2031. The establishment of 15 DIA-CoEs across major institutes like IITs and IISc underscores the mission’s collaborative approach.

Globally, quantum communication is a strategic priority. China leads the field with its Micius satellite, which has demonstrated quantum links over distances exceeding 1,000 km. The United States and the European Union are also working toward secure urban quantum networks. While India’s quantum links are shorter in comparison, its progress within a democratic and resource-constrained environment is considered remarkable.

Strategic Importance

1. Cybersecurity Transformation: Quantum entanglement-based QKD offers fundamentally secure encryption. In contrast to current encryption methods, which can potentially be broken by powerful quantum computers, this system ensures that any eavesdropping attempt can be detected instantly, preventing data breaches before they occur. This makes it crucial for protecting sensitive information in areas like defense and finance.

2. Defense Readiness: The Indian Defense Ministry views this technology as pivotal for future warfare. With its ability to secure command systems and battlefield communications, it can become an essential component of modern military infrastructure. Its suitability for satellite-based and mobile communication platforms further increases its relevance.

3. Applications in Civilian Sectors: The technology is not limited to military use. It can also be implemented in commercial banking to secure transactions, in telecommunications to safeguard networks, and in public governance systems where secure data exchange is essential. As India’s digital economy continues to expand, such advancements are critical to preventing cyber losses, which crossed $10 billion in 2024.

4. Infrastructure Flexibility: The free-space approach offers an alternative to expensive fiber-optic deployments. This is especially beneficial for difficult terrains and dense cities where laying cables is challenging. It enhances the feasibility of building a nationwide quantum communication framework.

Technological Approach and Collaborative Framework

The project was executed under the DRDO’s Directorate of Futuristic Technology Management (DFTM) and implemented at the DIA-CoE in IIT Delhi. The entangled photons were transmitted across a free-space optical path, which required precise calibration to counteract atmospheric disturbances. The achieved QBER of under 7% demonstrates that the system performs effectively in real-world scenarios, a major advancement from earlier lab-constrained tests.

This success showcases the strength of India’s innovation ecosystem, which thrives on collaboration between academia, government, and private industry. The contributions of DRDO in defense technology, IIT Delhi’s academic rigor, and industry support combine to make the development model sustainable and scalable.

Potential Applications Across Sectors

The demonstrated quantum secure communication system has a wide range of use cases:

• Defense and Military: Ensuring secure communication in combat zones and across satellite networks.

• Banking and Finance: Protecting online banking platforms and safeguarding sensitive financial data.

• Telecommunications: Supporting quantum-encrypted 5G and emerging 6G networks, enhancing user data security.

• Quantum Internet Infrastructure: Serving as a precursor to a future quantum internet that would support interconnected quantum computers and advanced sensing applications like non-invasive medical diagnostics or stealth object detection.

The system’s free-space configuration is also an important step toward deploying space-based QKD using satellites, a domain where the Indian Space Research Organisation (ISRO) is expected to play a crucial role.

Challenges Ahead

1. Scaling the Technology: While the current experiment spans 1 km, much longer distances will be necessary to develop functional quantum communication networks. Achieving this will require improvements in photon generation, detection, and atmospheric compensation technologies.

2. High Setup Costs: Despite avoiding fiber optics, building a national quantum network still involves significant investment in specialized hardware, including photon detectors and entangled photon sources.

3. Global Competition: Other countries are making rapid strides in quantum technology. India must maintain a fast-paced research and development agenda to remain globally competitive.

4. Human Resource Shortage: There is currently a shortage of trained professionals in quantum science. India needs to scale up its education and training programs quickly to meet the projected demand of 50,000 quantum experts by 2030.

5. Environmental Limitations: Maintaining a low QBER in different geographical and weather conditions is a challenge that will need to be addressed for mass deployment.

Stakeholder Impact

• Government and Defense Agencies: The breakthrough supports national cybersecurity and aligns with policies such as Atmanirbhar Bharat, which seeks self-reliance in strategic technologies.

• Industry Players: Sectors like telecommunications and finance stand to gain from enhanced security, and startups working in quantum tech may benefit from increased funding and market interest.

• Academic Institutions: The success positions IIT Delhi and other DIA-CoEs as global centers for advanced quantum research.

• Global Reputation: India’s growing capabilities in quantum technology enhance its standing among emerging technology powers, creating opportunities for exporting secure communication solutions to developing regions.

Looking Ahead

This demonstration is a foundational step toward larger ambitions, such as integrating quantum communication into India’s national security grid and launching satellite-based QKD initiatives. ISRO’s planned involvement, in combination with the National Quantum Mission’s roadmap, could see a robust and secure nationwide quantum communication network by 2030. Enthusiasm from the public, reflected in numerous online posts and discussions, indicates broad support and recognition of the technology’s transformative potential.

Conclusion

The DRDO-IIT Delhi quantum communication experiment marks a historic advancement for India’s tech landscape. By demonstrating entanglement-based free-space QKD with high security and minimal error, India has joined a select group of nations pursuing next-generation secure communication systems. While there are still challenges to overcome, this success paves the way for a quantum-secure future across defense, industry, and civilian domains, furthering India’s role as a global leader in emerging technologies.