ഇന്ത്യ തദ്ദേശീയമായി വികസിപ്പിച്ച ക്വാണ്ടം കീ ഡിസ്ട്രിബ്യൂഷൻ (QKD) സാങ്കേതികവിദ്യ 5.56 കിലോമീറ്റർ ദൂരത്തിൽ വിജയകരമായി പരീക്ഷിച്ചു. ഭാവിയിലെ സൈബർ ഭീഷണികളെ നേരിടാൻ ഈ സാങ്കേതികവിദ്യ സഹായിക്കും. ബഹിരാകാശത്തുനിന്നും സുരക്ഷിതമായ ആശയവിനിമയം സാധ്യമാക്കുകയാണ് ഐഎസ്ആർഒയുടെ ലക്ഷ്യം. ക്വാണ്ടം ഭൗതികശാസ്ത്ര നിയമങ്ങൾ ഉപയോഗിക്കുന്നതിനാൽ ഈ സംവിധാനം ഹാക്ക് ചെയ്യാൻ അസാധ്യമാണ്.
India has taken another step towards building quantum-secure communication networks, successfully testing a 5.56-km quantum key distribution (QKD) link through open air.
The test was carried out on the night of September 27-28 by QNu Labs, BISAG-N and IIT Gandhinagar. They sent quantum-encoded light between BISAG-N and IIT Gandhinagar, which are 5.56 km apart.
The test showed that quantum communication can work reliably over several kilometres through the atmosphere.
The system recorded a quantum bit error rate below 5 per cent. In QKD, a lower error rate means a more secure connection. The system also generated secret keys at a speed of 230-260 bits per second.
In simple terms, the system could generate roughly one new AES-256 encryption key every second.
A major part of the test was QNu Labs' Pointing, Acquisition and Tracking (PAT) system. It kept the narrow light beam accurately pointed at the receiver over the entire 5.56-km distance.
The quantum keys were then used by BISAG-N's Vedic Kavach security system to encrypt and decrypt test messages.
The setup used two layers of security. The first was QKD, which creates encryption keys using quantum light. The second was post-quantum cryptography, designed to protect data even against future quantum computers.
This backup is important because a quantum link can be affected by clouds, atmospheric disturbances or problems in keeping the light beam aligned.
WHY DOES THIS MATTER?
Today's internet security depends heavily on systems such as RSA and ECC. Powerful quantum computers could one day break some of these encryption methods.
There is also a growing concern that attackers could steal encrypted data today and try to decode it years later when quantum computers become powerful enough.
QKD offers a different approach. It uses the basic laws of quantum physics to create secret keys. If someone tries to intercept the quantum signal, the signal changes. This can reveal that someone is trying to listen in.
But there is a problem. Quantum signals travelling through optical fibre lose strength over long distances. This makes it difficult to use fibre alone to secure a country as large as India.
That is where space comes in.
FROM 5.56 KM TO SPACE
The 5.56-km experiment is also important because it tests many of the technologies needed for satellite-based quantum communication.
A laser or quantum signal travelling horizontally through the atmosphere has to deal with turbulence, dust, noise and alignment problems. Testing these challenges on the ground helps prepare the technology for space.
ISRO is already working on this.
Its Quantum Technology Demonstration in Space (QuTDS) payload has been built, tested and delivered for an upcoming technology demonstration mission. The payload includes an optical system that can point towards another station and send quantum signals.
The next major step is SAQTI -- Secure Applications using Quantum and Optical Technologies by ISRO under the National Quantum Mission.
The programme aims to demonstrate quantum communication between satellites and ground stations, as well as between different satellites.
India's journey has moved from a 300-metre QKD test in 2021, to longer-distance demonstrations in 2022 and 2025, and now to 5.56 km in 2026.