How Quantum Computing Will Transform Cybersecurity

Right now, you’re most likely on a website, that has a lock in the upper left corner of the browser. Have you ever thought about what it means? It means, that you established a secure connection with the authority that serves the website i.e. established a shared secret key, that is used to encrypt the data before sending it, which prevents hackers see what you’re doing. Right now you’re on Medium, but if you were to visit your Bank Account, you’d be much more attentive to that.

As one might already hear, it’s already theoretically proven that quantum computers are able to break nowadays cryptosystems, which consequently means that all this security we are using nowadays is useless. But still, can we do something about it?

This post addresses how two parties can securely establish a shared secret utilizing the principles of quantum mechanics. You might think now:

“Wow, that’s got to be complicated”.

No, don’t run away, I will not derive any physics equation or talk about parallel universes. Initially, I will try to explain how we can visualize such mechanisms, and then we will tackle the definitions with some code examples in Python.

Before we can talk about how quantum information can be exchanged, we need to understand what is the basic unit of information in quantum computing, a so-called quantum bit or qubit (analogous to a classical bit in classical computers). For the purpose of this example, I will consider a qubit…