Quantum Key Distribution (QKD) — Unbreakable encryption for Next-Gen network security
Will you believe that particles like photons can secure our communications? It might sound like science fiction, but QKD is a reality. It seems almost magical, yet it’s happening right now, promising a future where privacy is guaranteed by the fundamental properties of the universe itself.
In this blog, we will explore what and how Quantum Key Distribution works and how BB84 protocol works. But before seeing how quantum key distribution works, to understand the quantum key distribution, I just want you to essentially know about some basic terminologies of quantum physics:
Photon — It is a quantum of light. Other than that, in this context of the blog try to remember the property of photons that, the photons are not just particles but also waves which can oscillate.
Polarization — It refers to the orientation of the oscillation of a photon’s electromagnetic field.
While transmitting a photon, the photon can be polarized to oscillate in a particular direction. Say: Horizontal polarization — the electric field oscillates horizontally.
Quantum Key Distribution (QKD) is a method for securely exchanging cryptographic keys between two parties (consider Ramesh and Suresh as the two parties).
To explain how QKD works, let me dig into a widely used QKD protocol named as BB84 protocol.
As a first part of the operation, Ramesh prepares a sequence of photons, each polarized randomly in one of four possible states: horizontal (0°), vertical (90°), +45°, and -45° and then sends the polarized photons to Suresh over a quantum channel.
Suresh randomly selects a basis (either it can be rectangular or diagonal) to measure the incoming photons.
Note: Rectangular accepts photons which are polarized both vertically and horizontally, and diagonal basis accepts photons which are polarized +45°, and -45°.
After the transmission, Suresh announces the basis he used for each photon over a public channel, without revealing the measurement outcomes. Afterwards, Ramesh compares Suresh’s announced bases with the bases he used to prepare the photons. They discard all measurements where the bases did not match, keeping only those where they did. This forms the raw key.
Finally, both Ramesh and Suresh publicly compares their raw key bits to estimate the error rate. If the error rate is high, they might understand that someone might have intercepted in between (may be). However, if the error rate is acceptable they proceed with the key exchange to perform a secured communication.
If you think the BB84 protocol is just full of theories, it is not what you think. The BB84 protocol has moved from theoretical concept to practical reality, with successful implementations in various settings
Why QKD is so special? — The most notable advantages which forces us to say that as an unbreakable encryption is because of its unconditional security. In addition to that, any attempt to eavesdrop on the quantum channel introduces detectable disturbances. Even if the photons are captured, the photon cloning are not possible which makes the eavesdropper to clone an exact photon. Thus, for these reasons it is prone to say that as unbreakable encryption method serving the future with greater security.
In this digital era where security being a concern, QKD makes it a promising solution for protecting sensitive information in an increasingly digital world.
If you have read this far, I hope you are finding it useful. If so you can buy me a coffee at https://buymeacoffee.com/ayyappansubramanian
For more such articles do subscribe www.hashtagtechnophile.com
Follow us on Instagram for quick bites!
Make sure you rate or comment this article and if you are finding it more useful do share & subscribe because that encourages me to write more
Cheers! Until next time…❤️