Introduction

In a landmark achievement marking India's entry into the quantum era, scientists from the Defence Research and Development Organisation (DRDO) and IIT Delhi have successfully demonstrated quantum secure communication over a distance of more than 1 km in open air. This breakthrough not only highlights India's growing expertise in quantum technologies but also sets the stage for future-proof cybersecurity infrastructure.

What Is Quantum Secure Communication?

Think of it like a secret language only two people can speak—and if anyone else even tries to listen, the message changes, and the spies get caught right away.

Quantum secure communication is built on the principles of quantum entanglement and Quantum Key Distribution (QKD). In simple terms:

Quantum entanglement links two particles so that any change in one instantly affects the other, no matter the distance.
QKD uses this property to share encryption keys between two parties. If anyone tries to intercept the key, the quantum state collapses—alerting both parties to the breach. That’s why it’s called unhackable communication.

So basically, it’s a way of sending messages that’s super safe and smart.

How Did They Do It?

Led by Prof. Bhaskar Kanseri’s research group at IIT Delhi, the team achieved free-space quantum communication using entangled photons transmitted through the air—without relying on optical fibers. Key highlights of the demonstration include:

A laser creates pairs of entangled photons.
One photon goes to the sender (called Alice), and the other goes to the receiver (called Bob).
Both Alice and Bob have special devices to measure the photons.
If their measurements match, they know the communication is secure.
If someone tries to spy, the measurements won’t match—and they’ll know something’s wrong.

They achieved a key rate of 240 bits per second (which is good for secure messages) and kept the error rate below 7%, which means the system was stable and reliable.

This project, funded by DRDO under the Directorate of Futuristic Technology Management (DFTM), is part of a broader initiative to develop photonic technologies for free-space QKD

Why Is This a Big Deal for India?

This success is important because:

It was done without using foreign technology—everything was built in India.
It supports India’s goal of becoming self-reliant in advanced tech (Atmanirbhar Bharat).
It’s a step toward building a quantum internet, where all communication is ultra-secure.
It can be used in defence, banking, government, and telecom to protect sensitive data.

Moreover, free-space QKD removes the need for installing optical fibers, making it perfect for remote or urban areas where setting up infrastructure is difficult.

It also aligns with India’s National Quantum Mission, which aims to develop a robust quantum ecosystem by 2031.

Quantum Entanglement: What Exactly is It?

Let’s understand this Quantum Entanglement properly more clearly and in simple way.

Imagine you have two magic coins. You flip one in Delhi and the other in New York. Now here’s the twist: no matter how far apart they are, if one lands on heads, the other instantly lands on tails. They’re always in sync, almost like they can "sense" each other’s outcome.

That’s pretty much the idea behind quantum entanglement.

Now, for Quantum view, Let’s replace the magic coins with two tiny particles—like photons—are created together in a special way so they’re entangled. After that, if something happens to one of them, the other responds instantly, even if it's miles or light-years away.

It may seem strange, and even Sir Albert Einstein referred to it as "spooky action at a distance," but experiments have proven that it is both real and reliable.

Here’s why it’s powerful for communication:

Until you measure them, entangled particles are in a mix of states (like a spinning coin).
When one is measured, it "locks in" a value—and the other does the same immediately.
If someone tries to spy on this process, the entanglement breaks, and the message becomes useless.

In quantum communication, this phenomenon is used to send highly secure messages. This is because any attempt to interfere with the system, messes the message itself.

That’s what makes quantum entanglement is one of the coolest and mind-blowing tool for building tomorrow’s unhackable internet.

Conclusion: India’s Quantum Journey Has Just Begun

The successful demonstration of quantum secure communication by DRDO and IIT Delhi isn’t just a scientific experiment—it’s a bold step of India into the future of Quantum Technology. By using the strange but powerful rules of quantum physics, Indian scientists have shown that it's possible to send messages that are practically impossible to hack.

This achievement proves three big things:

India can build advanced tech using homegrown resources
Quantum communication is no longer just theory—it’s working, right here and now
We’re laying the foundation for a safer, smarter digital future

As the country moves forward with its National Quantum Mission, such breakthroughs will help shape new kinds of internet, defense systems, and data protection—all built on the rock-solid rules of quantum science.

So, while the science may sound magical, the message is clear: India is ready for a quantum-secure world—and the journey has only just begun.

Thanks for reading till the end !!

Written with Curiosity & Shared with Love — Alok Sharma

The VibeUnwind — Simplifying science, one story at a time.

India’s Quantum Victory: DRDO & IIT Delhi Secure the Future

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