Quantum Key Distribution (QKD)

Published on 15 Oct 2025

• In a major milestone, India’s first Quantum Key Distribution (QKD) transmission over a 4-core Multi-Core Fibre (MCF) has been successfully tested by the Centre for Development of Telematics (C-DOT) and Sterlite Technologies Ltd (STL). 

• QKD is a secure way of sharing cryptographic keys (string of bits used to encrypt and decrypt messages) between two parties using the laws of quantum mechanics. 

• It uses quantum particles (usually photons) to generate a random key. 

• If anyone tries to intercept the key, the act of measuring the quantum particles disturbs them—alerting the sender and receiver to eavesdropping.

• Traditional optical fibres have one core (the part that carries light) but MCF enables multiple data streams through distinct cores in a single fibre, saving space and cost. 

• It also allows physical separation of quantum and classical signals, enabling simultaneous QKD and high-capacity data transmission without signal interference. 

• QKD ensures ultra-secure key sharing using quantum mechanics. 

• C-DOT is India’s telecom R&D body under the Department of Telecommunications.

https://terms.tta.or.kr/upload/image/terms2020/qkd1.jpg

Keywords:

Quantum Key Distribution QKD Encryption Multi-Core Fibre MCF Cryptography quantum mechanics photons optical fibres Telecommunication C-DOT Security Digital security Data seurity