|
Getting your Trinity Audio player ready...
|
In a groundbreaking experiment in the field of secure quantum communication, scientists at the Indian Institute of Technology Delhi (IIT-Delhi) have successfully attained a trusted-node-free quantum key distribution (QKD) of up to 380 kilometres in standard telecommunications fibre. They achieved an impressively low quantum bit error rate (QBER).
Trusted nodes are weak security loopholes and are vulnerable to several kinds of attacks. This long secure length is the highest achieved globally, not only in India, for the Differential Phase Shift (DPS) Quantum Key Distribution (QKD) protocol. The exceptionally low QBER achieved in this experiment makes the DPS QKD scheme highly resilient to both collective and individual attacks.
This capability makes it suitable for a wide range of applications, including defence and securing financial transactions, medical records, and confidential codes. Moreover, it can safeguard network communications like the Internet of Things (IoT) and has the potential to revolutionise the field of cybersecurity.
Associate professor at IIT-Delhi’s Physics Department and Optics and Photonics Centre, Bhaskar Kanseri, said, “This realisation using state-of-the-art technology would not only help in reducing the need for trusted nodes for intercity or long-distance quantum key exchange, increasing the security of the cryptography scheme but would also prove to be a crucial step towards the commercial production of long-distance secure practical QKD devices.”
In the realm of quantum communication, security is inherently ensured by the fundamental principles of quantum physics, and this security cannot be compromised, not even with the use of quantum computers, he explained.
The team carried out this study using the baseline error optimisation method at their Experimental Quantum Interferometry and Polarisation (EQUIP) laboratory. Kanseri noted that the current DPS QKD demonstration has, for the first time, optimised most of the error sources. These errors mainly stem from the laser linewidth, modulation bandwidth, detector noise, and fibre dispersion. This has led to the lowest QBER (less than 2.5%) achieved to date, which stands as an international record for such a large fibre distance.
This study titled ‘Phase Encoded Quantum Key Distribution up to 380 km in Standard Telecom Grade Fiber Enabled By Baseline Error Optimization’ has been published in the Nature Scientific Reports journal.
In 2022, Kanseri’s team, in collaboration with the Defence Research and Development Organisation (DRDO), previously achieved a significant milestone in Indian quantum communication. They demonstrated the country’s first intercity quantum communication link between Vindhyanchal and Prayagraj. This accomplishment involved using more than 100 kilometres of commercial-grade underground dark optical fibre.
The Ministry of Defence said that the breakthrough was achieved over a commercial-grade optical fibre that was already available in the field. Upon measuring the performance parameters, they found that the results were within the reported international standards as sifted key rates of up to 10KHz. The technology has enabled security agencies to plan a quantum communication network with an indigenous technology backbone.
DRDO scientists have said that the work being done on QKD technology at the organisation will be used to enable start-ups and small and medium enterprises in the domain of quantum information technologies. It will also help define standards and formulate crypto technology-related policies that can use the QKD system for more secure “key management” for current and future military cryptographic systems.
