India has demonstrated its first 5.56 km Free-Space Quantum Key Distribution (QKD) link, marking an important step in quantum communication and cybersecurity. The demonstration was carried out by QNu Labs, BISAG-N and IIT Gandhinagar in Gujarat.
The technology can help protect sensitive information by using the principles of quantum mechanics to create secure encryption keys.
What Is Quantum Key Distribution (QKD)?
Quantum Key Distribution (QKD) is a technology that uses the principles of quantum mechanics to create and share secret encryption keys between two users.
These keys help encrypt and decrypt messages so that sensitive information can be protected from unauthorised access.
Unlike conventional encryption, QKD uses the properties of quantum particles to help detect attempts to intercept the key exchange.
How Does Free-Space Quantum Key Distribution Work?
Free-space QKD sends quantum signals through the atmosphere instead of using optical fibre cables for the entire communication link.
Its working involves the following steps:
- Generation of quantum signals: A device generates optical signals for creating secure keys.
- Transmission of signals: The signals travel through open space from a transmitter to a receiver.
- Key generation: Both users process the measurement results to establish a shared secret key.
- Security check: The error rate is checked to identify possible interference.
- Secure communication: The generated key is used to encrypt and decrypt messages.
This technology can be useful where laying optical fibre cables is difficult, provided suitable line-of-sight and atmospheric conditions are available.
Also Read:- Quantum Communication
Technologies Used in the Demonstration
The demonstration used various technologies which has been highlighted below in the table.
| Technologies Used in the Demonstration | |
|
Technology |
Simple Explanation |
|
Armos |
A hardware device developed by QNu Labs for Quantum Key Distribution. |
|
Vedic Kavach |
A security platform developed by BISAG-N to protect digital communication. |
|
Quantum Random Number Generation (QRNG) |
Uses quantum processes to generate random numbers for security applications. |
|
Post-Quantum Cryptography (PQC) |
Uses mathematical methods designed to protect information against attacks from quantum computers. |
|
Pointing, Acquisition and Tracking (PAT) |
Helps keep the transmitter and receiver properly aligned during communication. |
Difference Between QKD and Post-Quantum Cryptography
Both technologies aim to protect information from future cyber threats, but they work differently.
| Difference Between QKD and Post-Quantum Cryptography | ||
|
Basis |
Quantum Key Distribution (QKD) |
Post-Quantum Cryptography (PQC) |
|
Working |
Uses principles of quantum mechanics. |
Uses mathematical algorithms. |
|
Main purpose |
Helps establish secure encryption keys. |
Protects information using quantum-resistant algorithms. |
|
Equipment |
Requires specialised quantum devices. |
Can generally work on conventional computers. |
|
Security method |
Uses quantum properties to help detect interception. |
Uses algorithms designed to resist attacks from quantum computers. |
Significance of India’s Free-Space QKD Demonstration
- Better cybersecurity: It can help protect sensitive information from cyberattacks.
- National security: Quantum communication can support secure communication for defence and strategic organisations.
- Satellite communication: Free-space QKD can support future research on secure communication between satellites and ground stations.
- Government communication: It may help protect sensitive government data.
- Indigenous technology: The demonstration supports India’s efforts to develop domestic quantum technologies.
- Future communication networks: It provides a foundation for research into longer-distance quantum communication.
- Reduced dependence on fibre: Free-space links can be useful in areas where laying optical fibre cables is difficult.
Last updated on Oct, 2026
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India’s First 5.56 km Free‑Space Quantum Key Distribution FAQs
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