In News:

A Bengaluru-based quantum technology startup, QNu Labs Pvt. Ltd., supported by the Department of Science and Technology (DST) under the National Quantum Mission (NQM), has successfully demonstrated India’s first large-scale Quantum Key Distribution (QKD) network spanning over 500 kilometres.
The demonstration was formally announced during the Emerging Science, Technology and Innovation Conclave (ESTIC) 2025.

Institutional and Strategic Support

• Funding Support: I-Hub Quantum Technology Foundation (Technology Innovation Hub under the National Mission on Interdisciplinary Cyber-Physical Systems – NMICPS, hosted at IISER Pune)
• Defence Collaboration: Indian Army (Southern Command) and Corps of Signals
• Model of Collaboration: STRIDE – Synergy of Technology, Research, Industry and Defence Ecosystem

What is Quantum Key Distribution (QKD)?

• Quantum Key Distribution is a quantum-secure communication technology that uses the principles of quantum mechanics to generate and exchange encryption keys between two parties.
• Key principle: Any attempt to intercept or observe quantum information disturbs its state, making eavesdropping immediately detectable, unlike classical encryption methods.

How QKD Works

• Transmits photons (light particles) through optical fibre
• Information is encoded as qubits
• Measurement or cloning by an intruder alters quantum states
• After error correction and privacy amplification, communicating parties obtain a shared secret key
• The key is used for end-to-end encrypted communication

Types of QKD

• Prepare-and-Measure Protocols: Example – BB84 protocol (most widely used)
• Entanglement-Based Protocols: Uses entangled photon pairs for instant intrusion detection
• DV-QKD (Discrete Variable): Photon-based detection
• CV-QKD (Continuous Variable): Uses amplitude and phase of laser light

Key Features of India’s 500 km QKD Network

• Distance: Over 500 km quantum-secure link
• Infrastructure: Deployed on existing optical fibre networks
• Architecture: Multiple trusted nodes to enable long-distance secure key exchange
• Hardware Integration:
  • Quantum Suraksha Kavach for high-grade data protection
  • QSIP (Quantum Random Number Generator System in Package) for quantum-certified randomness
• Latency & Security: Resistant to both current cyber threats and future quantum computing-based attacks

The test-bed optical fibre network was specially engineered by Southern Command Signals, with selective access provided by the Indian Army in the Rajasthan sector, enabling real-world validation.