## The quantum computer and cybersecurity.

## Quantum computer involve total security, but at the same time absolute vulnerability. How is this paradox possible? Read on and find out!

But have you heard about superposition of states? Qubit? These two are basic terms regarding quantum computing; the new paradigm of computing that has been developing for four decades; and seeks to revolutionize the world of data storage, processing and transmission since Paul Benioff proposed the idea. Nowadays; it’s not a mere idea, but a reality that will change computing forever. **So; let’s learn more about quantum computer.**

### What is a quantum computer?

Quantum mechanics studies nature at the atomic and subatomic level. In this field of science; it has been discovered that particles have the characteristic of being able to remain in two states at the same time; a true superposition of matter. And it is on this basic knowledge of physics that quantum computing is built; as surprising as it is complex.

As you know; traditional computers work with bits, the minimum unit of information in computing. This is equivalent to the selection between two probable possibilities (exemplified as 1 and 0). All the information a computer can store and handle is stored; you could say, in binary strings of 1 and 0; and it is limited by the amount of information that can fit in those strings. **But how would it be if more information could fit in a string without the need for more bits?**

This is where the qubit or quantum bit comes in, created from the laws of the superposition of matter at the quantum level. While a conventional bit can only take a single value at a time **(1 or 0)**, the qubit can take several values simultaneously, it can be **0, 1, or 1 and 0** at the same time.

Quantum computers make use of these units of information whose variety of states allow them to perform multiple calculations and operations at the same time, thereby exponentially increasing their processing and storage capacity compared to traditional computers.

And that’s a quantum computer, a fast computer capable of performing multiple processes simultaneously in a literal sense.

### Traditional Computer versus Quantum Computer

Besides the processing speed; and the use of the bit in the traditional computer and the qubit in the quantum computer;** there are other differences worth noting:**

**Functions:**The quantum computer is not intended for everyday or domestic use; as is the case with the common computer; mainly because in that space there is no need to process titanic amounts of information.**Architecture:**The composition of quantum computers lacks memory and processor. These devices only have a set of qubits that ensure their operation. As you can see, traditional computers have a more complex architecture.**Programming language:**Just as they lack memory and processors, a quantum computer doesn’t have its own coding language and work through the use and development of very particular algorithms. Unlike traditional computers, quantum computers don’t use Java, SQL or Python, or any other programming language.

Now, it’s time to address the issue that concerns us, which is the of quantum computing security…

### Security in the quantum world: a duality

The quantum computer creates two diametrically opposed cases related to computer security and encryption; one given by the speed of the machine’s calculation; and the other arising from the quantum nature of the computer: quantum computers could breach security as we know it; while taking cyber security to a new level never before thought of.

**Let’s first look at the case in which security is reinforced.**

### Quantum cryptography

Quantum computers are expected to be capable of performing tasks that traditional computers cannot; and this statement also includes encryption.

* Quantum cryptography*; refers to the application of quantum mechanics for the development of an encryption system, whose infallibility is practically total; it also protects messages even from being intercepted.

Also employs two phenomena of quantum mechanics, which are what give it its high level of security. These are decoherence and quantum entanglement.

The previous point refers to the fact that the quantum state of any system cannot be measured without altering that system; in other words, by observing something at the quantum level, the object invariably changes. As far as quantum cryptography is concerned; it is used in such a way that if a third party intercepts the message, the whole process would be altered; revealing an intrusion.

Quantum entanglement is the subatomic phenomenon that consists of the “connection” or link between a given particle and another, regardless of distance, which makes it possible that if one of the two particles is altered; the other is also altered immediately; without there being a channel to link them. Quantum cryptography uses quantum entanglement to send information without any means of transmission, so there would be no way for information to leak.

Finally; a message encrypted in this way has the most complex and secure encryption possible; thanks to the processing capacity of quantum computers.

So it seems then that quantum computing security will bring with it a splendid future in terms of cyber security. Infallible security systems, messages that cannot be intercepted… A utopia. But there is another problem…

### Quantum computers and traditional encryption

As I’ve been saying, quantum computers are capable of performing calculations at a potentially higher speed than ordinary computers. And this brings with it some problems in relation to the encryption systems used until now.

It’s possible to lock data by means of keys; as is known. If the encryption system is strong enough; the only way for an * attacker* to get through is by using all possible combinations until he finds the correct key. In other cases, it’s necessary to make as many calculations as necessary to find the key. But this is not practical; this could take thousands of years or need thousands of processors; so if the encryption is strong, the attacker’s only option is to give up.

But if it were a quantum computer that was attacking; that wouldn’t have to be the case. The processes needed to find the key would be much more immediate; to the point that if a traditional computer took 100 hours to find the right combination of characters; a quantum computer would take only 1. And this speed gap just widens over time. Therefore; **a quantum computer would easily destroy the encryption system of an ordinary computer.**

In a world where one group handles quantum computing and another group does not; there is a clear relationship of submission to quantum supremacy. It would only take a few clicks and minutes for all our information; even encrypted with the strongest traditional system of the moment; to be under the control of the dominant group.

And that’s how quantum computers can provide greater security; but at the same time weaken it for some of us.

### There is nothing to fear… For now

But the truth is that, for now; there’s nothing to fear. Quantum computers are still far from being fully functional; not to mention the fact that the most powerful quantum computer still doesn’t outperform the most powerful conventional computer. Despite this; there is no doubt that quantum computing is the future. For sure; the quantum computing security will bring giant advances; but only for some. *The rest will remain vulnerable.*