Quantum Key Distribution (QKD) Technology

A group of scientists from the Defence Research and Development Organisation (DRDO) and the Indian Institute of Technology (IIT) Delhi achieved a significant milestone by successfully demonstrating a Quantum Key Distribution link between Prayagraj and Vindhyachal in Uttar Pradesh. This groundbreaking achievement covers a distance of over 100 kilometers. Essentially, they showcased a homegrown technology for safely transferring cryptographic keys, enhancing the security of military-grade communication systems. Previously, China’s satellite Micius had sent light particles to Earth to establish an extremely secure communication link.

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What is Quantum Key Distribution Technology?

QKD, also called Quantum Cryptography, is a mechanism to develop secure communication.
It provides a way of distributing and sharing secret keys that are necessary for cryptographic protocols.
- Cryptography is the study of secure communications techniques that allow only the sender and intended recipient of a message to view its contents.
- Cryptographic algorithms and protocols are necessary to keep a system secure, particularly when communicating through an untrusted network such as the Internet.
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.

What are the Two Main Categories of QKD?

Prepare-and-Measure Protocols:

It focuses on measuring unknown quantum states and detecting eavesdropping, as well as assessing the amount of intercepted data.
This protocol helps us measure quantum states we don’t know about. It’s like a security check to catch spies and figure out how much information they might have snatched.

Entanglement-based Protocols:

It focuses on quantum states where two objects are linked, creating a joint quantum state. The concept of entanglement means that measuring one object affects the other, providing a way to detect eavesdropping.
This method deals with quantum states where two things are connected. If someone tries to mess with one, it immediately alerts the others, acting like a built-in alarm system against sneaky eavesdroppers.

How does the Quantum Key Distribution Work?

QKD stands for Quantum Key Distribution.
In QKD, encryption keys are sent as ‘qubits,’ which are like the building blocks of information in the quantum world.
These qubits are sent through optical fibers, which are really good at sending a lot of data quickly and over long distances. They work by bouncing light around inside them.
QKD lets two people who are far apart create a secret key together, even if they didn’t have a key to start with.
The key is made up of random secret bits, and this process happens through the exchange of qubits.
To make sure that the people talking are who they say they are, QKD uses various cryptographic methods for authentication.
QKD takes a regular communication channel and turns it into a secure one.
If someone tries to listen in on the conversation without permission, the qubits get disturbed.
This disturbance causes errors in the transmission, immediately letting the real users know that something fishy is going on.

Why is QKD Needed?

In the face of rapidly advancing Quantum Computing, QKD is crucial to secure data transmitted through our current communication networks.
Quantum Technologies are broadly categorized into four areas: Quantum Computing, Quantum Communications, Quantum Sensors, and Quantum Materials.
Quantum technology opens up opportunities for start-ups and small to medium-sized enterprises (SMEs) in the field of quantum information.
QKD enables security agencies to plan and implement a secure quantum communication network using indigenous technology.
The strength of encryption lies in the unbreakable nature of the data carried by photons.
Photons, the carriers of data, cannot be perfectly copied. Any attempt to measure them will disturb the data, leaving a trace if someone tries to intercept it.

What are the Challenges associated with the QKD?

Challenges in Implementing QKD Infrastructure: While Quantum Key Distribution (QKD) promises perfect security in theory, practical implementation faces hurdles. Issues with tools like single photon detectors introduce security vulnerabilities.

Photon Travel Distance Limitations: Current fiber optic cables have a restricted range for carrying photons. Generally, they are effective up to approximately 100 km. This limitation impacts the practical deployment of QKD systems.

Use of QKD

QKD relies on having a secure traditional communication channel already set up. This means that the people involved have likely shared a secret key beforehand, ensuring a basic level of security.
The reason QKD is getting more attention is because as quantum computers become more common, there’s a growing risk that attackers could use their quantum capabilities to break into existing encryption methods. This makes QKD more important for enhancing security in the quantum era.
Even without using Quantum Key Distribution (QKD), we can still make a communication system very secure. There are advanced encryption standards available that provide strong protection.

Way Forward

We need to make sure that startups and big tech companies working on quantum technology stay on the right track. Let’s come up with a plan for the next 10-15 years that uses our resources wisely. We want to concentrate on the most important areas that will not only help our economy but also give us strategic advantages.

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