All You Need To Know About Quantum Cryptography

To break down what Quantum Cryptography means, let’s look at the two terms: Quantum is the study of matter, energy and its interaction at the subatomic level. Cryptography refers to the process of encrypting data so that only authorized individuals with the right passkey can decrypt and read it. When these two concepts come together, we get Quantum Cryptography!

Traditional cryptography uses the technique of mathematically scrambling data so that only people with the right key can access it. The asymmetric key distribution method employs two keys—a public key to encrypt messages and a private key to decode them, while the symmetric key uses just one key – for both data encryption and decryption. These two methods are most commonly used in traditional cryptography.

Since Quantum Cryptography is based on quantum mechanics and subatomic physics, it offers much better encryption than traditional cryptographic methods. This is because the act of observing a message in transit changes the expected outcome, informing both the sender and receiver about the presence of an eavesdropper. (No, we’re not taking a page from Inception’s script – this is real technology!)

Quantum Cryptography is different from traditional cryptographic systems as it relies on physics, rather than mathematics, as its key security model. Let’s analyze the technology on a subatomic scale (pun intended!).
 

Quantum Cryptography Simplified

Quantum Cryptography is a system that cannot be compromised without the knowledge of either the sender or the receiver. This makes it impossible to copy, modify or view the data encoded in a quantum state without disclosing the fact to the sender or recipient. In Quantum Cryptography, data is transmitted over fiber optic wire using individual light particles, or photons, to represent binary bits. This system is extremely secure as it relies on quantum mechanical properties and not mathematical encryption.

These secure properties of Quantum Cryptography include:
 

• Photons, or light particles, that can exist in more than one place or state at a time (superposition)

• Data stored in a quantum state cannot be observed without changing or disturbing it (observer effect)

• Entire light particles cannot be copied (no-cloning theorem)

These properties combine to ensure that third-party entities can’t intrude on the system without disturbing it. Although it may sound complex, we’re here to simplify it!

Before we get into how it works, let’s take a quick tour of its history.
 

Evolution And Origins Of Quantum Cryptography

You must be wondering, who could even come up with such an abstract concept? Here’s the answer:

In the early 1970s, Stephen Wiesner introduced the concept of quantum conjugate coding at Columbia University in New York. His seminal academic paper called "Conjugate Coding" was rejected by the IEEE Information Theory Society. However, he got his due credit when it was eventually published in 1983 by SIGACT News. #HappyEnding

Following this publication, Quantum Cryptography started gaining interest. The modern concept is based on a model that was developed in 1984, called BB84. This was essentially a quantum key distribution protocol developed by Charles Bennett and Gilles Brassard at Université de Montréal, taking inspiration from Wiesner’s work.

Then, in 1991, Artur Ekert proposed a secure key distribution protocol that provided device-independent quantum key distribution. This was a major innovation that further progressed the field of Quantum Cryptography.

A 10-node Quantum Key Distribution network was created in collaboration with Boston University, Harvard University and IBM Research. The Defense Advanced Research Projects Agency (DARPA) Quantum Network used it from 2002 to 2007.

Since then, Quantum Cryptography has been employed to provide secure communication between two authorized users by encrypting data. That sounds fascinating – but not as fascinating as how it all works.

Read on!
 

How Does Quantum Cryptography Work?

 

Assume you want to exchange messages securely with a friend named Bob. You both know how cyber-attacks can decipher traditional encryption systems, so you decide to use Quantum Cryptography.

You initiate the conversation by sending Bob a key, which in a quantum system is a stream of photons traveling in one direction, with each photon representing either a 0 or 1. However, unlike traditional computer bits, these photons have unique quantum properties such as oscillation and vibration.

Now, before your message reaches Bob, the Quantum Cryptography system filters the photons, such that certain photons pass through it with the same characteristics while others pass through with a changed state.

The photons now travel over an optical fiber toward the recipient, Bob. When Bob receives the stream of photons, he does not know the correct polarization of each photon as they’ve been randomly filtered. Well, Bob goes ahead and chooses a polarization at random. He sends you the details using the same secure system. Now, you can compare how Bob polarized the key compared to you, which allows you to let Bob know which polarizer to use on each photon. With the correct polarization in place, the “incorrect” photons are then discarded and the remaining sequence is the key you sent Bob at the outset. Now, you can use this key to encrypt all future communications!

Oh no! What’s this? Your mutual friend James is trying to eavesdrop. However, unlike Bob, James cannot confirm which polarizer was used for each photon. More importantly, if James tries using some random combination of the polarization filter, it will change the photon positions that you and Bob would expect to see. Yes, it sounds strange but that’s the power of quantum physics!

Essentially, Quantum Cryptography operates on three levels:
 

• Photons are sent through a filter called a polarizer, which randomly assigns each photon a different polarization and a bit designation (1 or 0).

• When the photons arrive at the receiver, beam splitters are used to "read" their polarization. The receiver must make an educated guess as to which beam splitter to use for each photon.

• The receiver notifies the sender of the beam splitter that was used for each photon. The sender compares that data with the polarizer that was used to transmit the key and informs about the polarizer values that need to be corrected. Through this confirmation, the photons that were read using the incorrect beam splitter can be discarded and the resulting sequence becomes the key.

However, where can we even use this complex system? Turns out, there are various applications. Scroll on to find out about them!
 

Applications Of Quantum Cryptography

Quantum Cryptography can potentially revolutionize the way we share sensitive data by providing a secure communication channel that is immune to decryption. Some of the common applications of Quantum Cryptography include:
 

• Financial Transactions

  Cybercriminals can't intercept or steal sensitive financial information as Quantum Cryptography offers a secure communication channel for financial transactions.

• Military And Government Communication

  Military and government organizations can securely view, access, modify and share sensitive information without worrying about being intercepted.

• Healthcare

  Quantum Cryptography can be vital in protecting patient records, patient information, bank details, private research data, etc. in medical databases.

• Internet of Things (IoT)

  Due to their low computing power, IoT devices are highly susceptible to cyber-attacks and ransomware. Yet, with Quantum Cryptography, inter-device communication within the IoT network can be secured.

Impressed yet? Well, Quantum Cryptography offers more benefits – here’s a list of the main advantages.
 

Benefits Of Quantum Cryptography

Well, that’s just the headline; here are some more benefits that come with Quantum Cryptography:
 

• Provides Secure Communication Channels

  Mathematical encryption algorithms can be difficult but not impossible to crack. As Quantum Cryptography is based on the laws of quantum physics, it is a more sophisticated and secure method of encryption.

• Detects Eavesdropping By Third Parties

  If unauthorized individuals attempt to decrypt the encoded data, the quantum state changes, which modifies the expected outcome. This informs the sender and recipient about the risk so they can create a new key.

• Offers Improved Protection

  Various Quantum Cryptography protocols can be deployed for business security. For instance, Quantum Key Distribution methods can be combined with classical encryption approaches to bolster security.

Now, for the most exciting part – no, we’re not announcing the sequel to Inception (although we hope Nolan makes that happen!).

We’re talking about the future of Quantum Cryptography!
 

Future Trends In Quantum Cryptography

 
Although still in its infancy, Quantum Computing is seeing a lot of innovation. As encryption is an ever-changing security aspect, businesses are looking into using Quantum Cryptography in a variety of applications. Despite using fiber optics, the challenge with the transmission of quantum-encrypted messages was its range.

However, in 2021, a Swiss quantum technology company called Terra Quantum announced a breakthrough for Quantum Cryptography in terms of range. Terra Quantum's advancement could make it possible to transmit Quantum Cryptography keys over 2400 miles, compared to the previous distance restriction of 250 to 310 miles.

Furthermore, this innovation might enable companies to share quantum keys using traditional optical fiber lines that are already being used in telecom networks, rather than constructing new optical fiber lines. We're sure this technology will see mass adoption if quantum computers become commonplace!
 

Conclusion

 

The business demand for unbreakable and impenetrable encryption is rising. With innovation in quantum computing pushing the envelope further each day, Quantum Cryptography is looming on the horizon. Quantum-based encryption systems such as Quantum Cryptography address the growing risk of sensitive corporate data and other critical information stored across databases. Well, you’ve now learnt everything about Quantum Cryptography!