The Limited Times

Now you can see non-English news...

Will Quantum Computers Kill Traditional Cryptography?

2020-10-27T02:29:46.817Z


Thanks to cryptographic techniques, we can send encrypted messages through insecure channels. But technological advance will make them obsolete. Quantum computers will be able to easily break some of the more common cryptographic methods.


Alicia sends Bernardo a box with an open padlock.

Bernardo puts his message in the box, closes the padlock, and returns it to Alicia.

Nobody can open the box, nobody can read the message.

Except Alicia, of course, who has the key to the padlock.

In this example the box would be the public key and Alice's key would be the private key (cryptography that uses two keys is called asymmetric, in contrast to one that uses only one, which is called symmetric).

Deciphering a message requires knowing both.

This is one of the most common methods in conventional cryptography that underpins our digital world today.

One of the ways these two keys are protected is by factoring.

You multiply the number 3 and 5. The result is 15. Easy.

Now let's do it the other way around: what two numbers do you have to multiply to get 15?

It is also easy: 3 and 5. An ordinary human brain, with notions of basic arithmetic, solves it in a snap.

This process is factoring: any whole number can be decomposed into prime numbers (primes are like the atoms of numbers).

But now imagine that you are given a huge number, 400 digits.

What numbers do you have to multiply to get that long number like a sausage?

That is not so easy anymore.

"The resources required for this calculation increase exponentially with the size of the key," explains Vicente Martín, director of the Center for Computational Simulation at the Polytechnic University of Madrid (UPM).

Now there is no human brain worth it.

And it is difficult even for computers.

A 1024-bit key can take thousands of years to find.

It is possible, yes, but not in reasonable times.

The problem of factoring large integers is used to encrypt information, it is used in our daily lives, for example, to protect credit cards or Internet purchases.

The RSA system, created in 1977, is the first and most widely used based on factoring.

Other more common methods are those that use elliptic curves or discrete logarithms.

"This type of cryptography is based on solving mathematical problems that are very complex," explains Antonio Acín, Icrea research professor at the Castelldefels Institute of Photonic Sciences (IFCO).

As computers become more and more powerful, it is necessary to use increasingly longer numbers.

At its core, this is a mathematical problem that just needs more computing power.

That is, as technology advances, security is less and less.

The quantum computer

But we are facing a paradigm shift in computing: the quantum computer, which already knows its first versions (up to 128 qubits, where the qubit is the quantum bit that is not a 1 or a 0, like the classical bit, it can be both at the same time).

If a current computer would take a long number to factor the lifetime of the universe from the Big Bang to now, a quantum computer that is sufficiently advanced, much more powerful, could do it in a reasonable time, so that the security of our bank cards , our electronic IDs or our bitcoins would be in a loop.

Breaking encryption systems can turn the world upside down.

A historical example is that of the mathematician Alan Turing, a computer pioneer, who managed to break the code of the Enigma machine that the Nazis used to encrypt their communications.

It is estimated that it saved two years of war and saved tens of thousands of lives.

It is true that quantum computers are still in the early stages of their development.

“But there is data that should be kept secret for a long time.

For example, health records: if the quantum computer is fully developed in 20 years, then they would no longer be safe ”, says Martín.

"You have to start working now to have reaction time: technology doesn't change overnight."

Indeed, encryption systems are heavily embedded in much of the technology we use, so changing them can take a lot of time and investment.

"Given the speed with which quantum computing is evolving, the world may not have much time to deal with this new security threat," Martin Giles writes in the MIT Technology Review.

It is not uncommon for encryption methods to become obsolete as time goes by and the computing capacity of machines improves.

For example, the DES encryption algorithm was created in 1974. “So experts calculated that building a machine to break DES would cost $ 20 million (...).

Today you can do it from your laptop, ”writes cryptographer Bruce Schneier in his book Click here to kill them all (Today's Topics, 2019).

One of the reasons is that it uses a short, 56-bit key.

A brute force attack (that is, putting a computer to try all possible keys) breaks it in a short time.

"Keys that not so long ago were safe, now they are not," says Martín.

This is where quantum cryptography comes in.

It works in such a way that to burst it is not about solving a tough math problem, but about violating the very laws of physics.

Security is very high.

How does it work?

Quantum cryptography

Now Alicia sends Bernardo a message encrypted in a quantum particle: for example, a photon through a fiber optic cable.

As is known, due to the laws of quantum mechanics, when an observer observes a quantum system he modifies it (it is the famous Heisenberg principle of uncertainty).

So if Bernardo received the modified message, he would have evidence that someone has been spying on his communications.

No hacker can manipulate a qubit without modifying it, qubits cannot be copied and the attacker would be exposed.

This way of transmitting information is, very roughly, quantum cryptography.

"Quantum cryptography is robust against a quantum computer," explains Acín.

A fundamental difference between conventional and quantum cryptography is that, although the first was based on solving complex problems, the second “is based on the physical properties of matter, which does not depend on the power of computers to decipher it. .

In fact, in order to break the security of these communications, the laws of physics would have to be broken, ”says Acín.

And the laws of physics are supposed to be unbreakable.

Quantum Key Distribution (QKD) is the most developed quantum method for the transmission of secure information and the first to be marketed (companies like Quantum Xchange already offer it for sale to those interested in providing maximum security for their communications).

Here information is transmitted over the networks using classical bits, but encrypted with keys that have been transmitted using qubits, in a kind of hybrid between classical and quantum technologies.

"We can now converge classical and quantum networks in the existing fiber optic infrastructure," explains Martín.

But that's not all, there is still another type of cryptography in development, post-quantum.

"This type of cryptography uses again the resolution of complex problems, this time difficult even for a quantum computer," says Acín.

This is the case of reticular cryptography and other models.

The United States National Institute of Standards and Technology launched the challenge in 2016 to develop cryptographic standards that are resistant to quantum computing.

In 2022 we will know the results, although we know that most of the finalists use the lattice approach: it is a mathematical problem that is difficult enough, but it could also be compatible in terms of time and resources with real technology.

What does tomorrow hold for us?

Should we expect an environment with more cyber insecurities?

"The level of sophistication of threats is increasing because people's awareness, fortunately, is also growing," explains Hernández.

And he continues with a paradoxical fact: “But that does not mean that the most lucrative threats are very complex.

The malware with the highest incidence in Spain is Conficker, which was developed in 2007 and after six months it had been solved.

That means that there are still many systems in this country that have not been updated since then ”.

Quantum Internet Path

Although quantum communication is still under development, there are strong stakes for it.

For example, OpenQKD, the embryo of the EuroQCI (Quantum Communication Infrastructure), a European quantum network, that is, a physical infrastructure through which to carry out quantum communications between different places.

It begins to be generated in places like Paris, Athens, Berlin or Madrid, where it will be one of the largest in the world when it is installed (like so many other things, it has been slowed down by the pandemic).

In these infrastructures, work is being done to develop communication and quantum cryptography in all its aspects.

In addition, the European Civiq project, in which IFCO and UPM participate, among other organizations (such as Telefónica), is working on developing services and applications based on technology and quantum cryptography.

Last June, China managed to send information in this way from a satellite to two points on the Earth's surface 1,200 kilometers apart.

Last year, several countries of the European Union agreed to work on deploying a quantum communication network in Europe for the next ten years (the aforementioned EuroQCI), which will include national terrestrial networks and communication satellites for long distances (quantum communication through satellite is simpler than through fiber optic terrestrial networks: photons encounter fewer obstacles when traveling through the air than through a material medium).

This advance "will help Europe to protect its critical infrastructure and its encryption systems against cyber threats," according to the EU, including smart energy networks, air traffic control, banks or health facilities.

It will also allow data centers to store and exchange information securely and will preserve the long-term privacy of data from both citizens and institutions.

"The plan is for this infrastructure to be the backbone of the future quantum Internet," says the EU.

Source: elparis

All news articles on 2020-10-27

You may like

Trends 24h

Latest

© Communities 2019 - Privacy

The information on this site is from external sources that are not under our control.
The inclusion of any links does not necessarily imply a recommendation or endorse the views expressed within them.