Chennai:  For the first time in the country, the 
 Indian Space Research Organisation (ISRO) has successfully 
 demonstrated free-space Quantum Communication over a 
 distance of 300 m. 
In a release here ISRO said, a number of key technologies were 
developed indigenously to accomplish this major feat, which 
included the use of indigenously developed NAVIC receiver 
for time synchronization between the transmitter and receiver 
modules, and gimbal mechanism systems instead of bulky large
aperture telescopes for optical alignment.
The demonstration has included live video-conferencing using 
quantum-key-encrypted signals. 
This is a major milestone achievement for unconditionally 
secured satellite data communication using quantum technologies.
The Quantum Key Distribution (QKD) technology underpins Quantum 
Communication technology that ensures unconditional data security 
by virtue of the principles of quantum mechanics, which is not 
possible with the conventional encryption systems. 
The conventional cryptosystems used for data-encryption rely on 
the complexity of mathematical algorithms, whereas the security 
offered by quantum communication is based on the laws of physics. 
”Therefore, quantum cryptography is considered as ‘future-proof’, 
since no future advancements in the computational power can break 
quantum-cryptosystem”, the release said. 
The free-space QKD was demonstrated at Space Applications Centre 
(SAC), Ahmedabad, between two line-of-sight buildings within the 
campus. 
The experiment was performed at night, in order to ensure that 
there is no interference of the direct sunlight.
The experiment is a major breakthrough towards ISRO’s goal of 
demonstrating Satellite Based Quantum Communication (SBQC), 
where ISRO is gearing up to demonstrate the technology between 
two Indian ground stations.
 
			