In my previous blog post, you could read about classical cryptography and a fraction of the vast amount of use cases for quantum computers. In addition, we established that quantum computers make use of two particular phenomena: superposition and entanglement. In this blog post, you can read about why quantum cryptography is already a use case today for some organizations.

A classical computer will take longer than the current age of the universe to crack RSA-encryption, whereas a quantum computer will be capable to crack RSA-encryption in just seconds.

Harvesting the quantum world
As a result of the quantum behavior, quantum computers can calculate solutions to hard problems exponentially faster than all the computers that exist in the world today combined (including the most powerful supercomputers). Imagine the potential as follows. When you are computing the fastest route in a maze, a classical computer would have to decide at every junction to go one way or the other. This can be represented as going left (0) or right (1). A quantum computer, however, would not have to decide on one way: it just follows every path there can be at the same time by making use of superposition and entanglement. This can be represented as going left (0) and right (1). This allows for its exponential improvement in performance over classical computed bits.

Quantum Cryptography
Now, regarding cryptography, a classical computer will take longer than the current age of the universe to crack RSA-encryption (300 trillion years), whereas a quantum computer will be capable to crack RSA-encryption in just 10 seconds. That’s just the power of nature right there. So, do you have to be afraid right now? Not yet. At least, if you don’t care about the data you have today in 10 years. Quantum computers that can crack RSA-encryption will not exist for a while, but there are a couple of companies and governments that have to hurry right now. Imagine that you are able to steal information from a company or government today. Then you are probably not able to decrypt it right now. However, if you hold it on for 10 years, then a quantum computer can decrypt it fairly easily. This is only useful if the data is still relevant in 10 years. So, companies and governments that have such sensitive, time-invariant data that cannot be made public have to become resistant against quantum computing right now! Therefore, the National Institute of Standards and Technology is bringing together bright minds to come up with new encryption algorithms that are quantum resistant. But this takes time. And until then, sensitive, time-invariant data is at risk.

Were you intrigued by my posts? Rate them! And if you have questions, comments, or suggestions about this amazing topic, let me know below!

It is Blue Monday when you are leaving for the skiing holiday. You take the train to the airport, but everything is against you today. The train is delayed because the train table has been changed to bad-weather-conditions. Since you are waiting for the train to come, you decide to check your stock portfolio. Maybe that makes you a little bit more happy. Unfortunately, you lost money again. After one hour of delay, you arrive at the airport 30 minutes before departure. Luckily, you caught your flight. Just when you are chilling out, the pilot broadcasts that a stopover will be made because the airport of destination has become overcrowded with too many planes landing at the same time. After two hours of extra delay, you finally arrive at the ski resort. But then, Blue Monday really kicked in: your rheumatism begins showing its annoying symptoms again.

“Quantum computing could identify patterns that will allow us to identify something like COVID-19 earlier.” – Heather West, Senior Research Analyst at IDC

A quanta of solutions
This is an example with problems that occur to many people around the world at a daily rate. However, this might not be for too long anymore! Quantum computers are potentially capable to address aforementioned problems exponentially faster than contemporary computers. Scheduling, portfolio optimization, route optimization, and personalized medicine are just a small fraction of the vast amount of problems that quantum computers can potentially solve (see video below). If full quantum computers existed today, COVID-19 would not even be such an issue right now. But how? With quantum computers? That sounds like something of the far future? But it is closer than you think. Although mainstream use cases are probably out for more than 10 years from now, one use case is already important yesterday for some organizations: cryptography.

Classical cryptography
Most contemporary cryptography is based on RSA-encryption and is used by for example, websites, banks, and even some cryptocurrency. It is based on a mathematical problem that is called a one-way function. In this case, it means that it is easy to multiply two prime numbers and get a solution, but it is very hard to only have the solution and find the two corresponding prime numbers. For small prime numbers this is easy to do. But the larger the prime numbers get, the exponentially harder it becomes to solve. This is where the strength of quantum computing lies.

Magical behavior
Quantum computing is a form of computing that makes use of the laws of physics for the smallest particles in the universe, called quanta (hence: quantum computing). The laws of physics for these tiny particles are very different from what we are used to in our daily lives. This odd behavior is exactly what quantum computers make use of. Without going too much into the intricacies of the quantum world, this odd behavior results in two phenomena: superposition and entanglement. Shortly, superposition means that a particle can be at an infinite possible locations at the same time. Entanglement means that all these particles that are in a superposition are connected with each other: a change in one particle directly affects the other particle faster than the speed of light – this is not a lie! This might sound like magic to you, but it is not.

“Magic is just science that we don’t understand yet.” – Arthur C. Clarke

So, if you don’t understand it fully, that is ok. Just imagine that these quantum particles can behave in this strange way.

That is a lot to digest. So, take a break and come back later to read more about why quantum cryptography is already a use case today in my next blog post.