As usual, both sides have a point: when a tool is powerful, you have to make sure you know how to use it ethically and responsibly. With the widespread use of social media, we’re increasingly aware of the need to secure and guarantee the privacy of our personal data. The metaverse is no exception: its popularization means an increase in the amount of sensitive information that is shared on our behalf – from personal data to banking transactions.

Ensuring that all this information is transmitted securely requires legal and technical efforts of which the general public often remains unaware. Cybersecurity is the area involved with protecting systems and information against digital attacks, and it is in constant development as technological needs evolve and new threats emerge.

HOW DO WE SHARE SECRETS SECURELY?

Let’s imagine that we are British spies, at the service of His Majesty. If we wanted to send him a secret message, we could simply write it in such a way that each letter of the alphabet was replaced by the one immediately following it: A now stands for B, B now stands for C, etc. This process is just about one of the simplest, most intuitive, and oldest ways to encode a message: the Caesar cipher. We could make it more complex and substitute each letter of the alphabet for another, in no particular order, in what is called a Vigenère cipher.

In both cases, in order for His Majesty to understand the message, he would need to know what substitutions we made when writing it. Of course, anyone who got their hands on our little “cheat sheet” would be able to understand the messages sent. This is the weakness of symmetric cryptography, in which the security of the shared information depends on the parties involved knowing a secret key previously agreed upon. Today we use more complex symmetric cryptography protocols, such as the AES algorithm.

To talk about the other great family of cryptographic methods, I’m afraid we must turn to mathematics. Let’s start with the basics: multiplying two numbers is easy. We learn to do it in elementary school, and later we just do it with a calculator. The reverse process is somewhat more complicated: we also learn to separate a number into its factors in secondary school, but where is the key for factoring on our calculators?

It turns out that performing this operation is very difficult for conventional computers. There is currently no known classical algorithm that solves this problem efficiently: for a 200-digit number, the most recent experiment took 18 months to solve the problem and used 80 CPUs, consuming more than 50 years of computation time.

Asymmetric cryptography benefits from this great difficulty. Both His Majesty and his secret service have their own public keys, which are accessible to everyone, and which are based on multi-digit prime numbers. Thanks to the RSAalgorithm, these keys can be combined to disclose secrets: multiplying prime numbers is easy, but if someone intercepts this multiplication, it would be very difficult for them to know which two keys were used to create it.

THE QUANTUM THREAT TO CYBERSECURITY

Having gotten this far, we can hope that this whole cybersecurity thing will provide us with a certain level of trust. Our data should be safe behind all that math, right? This is how things have been for decades, and this is how things are today – except for a few cyberattacks. However, quantum computing (which everyone is already talking about) brings with it a threat that has been a theoretical concern for years.

Quantum computing entails an acceleration of certain specific tasks. Grover’s algorithm, which allows us to search unsorted databases, threatens symmetric cryptography. Using it, a hacker could try different secret keys twice as fast, doing so until he found the one that would allow him to decrypt our messages to His Majesty. To maintain the same levels of security, we would simply have to make our passwords twice as long.

However, it is public-key cryptography that is most threatened by the advantages of quantum computers. Shor’s algorithm is designed to solve the problem of factoring large numbers, the basis for the RSA algorithm. Yes, we could make our keys more secure by making them longer, but that wouldn’t bother a quantum hacker too much. If a classical computer takes 10 times as long to factor a key 10 times larger, a quantum computer may only need twice as long.

MODERN PROBLEMS REQUIRE MODERN SOLUTIONS

So, then… Is our personal data at the mercy of quantum computers? Fortunately, despite the clear theoretical advantages of quantum computing, it’s estimated that there are still 5-10 years left before quantum computers can really threaten today’s cybersecurity.

Meanwhile, cybersecurity experts are not standing idly by. In recent years, institutions such as the NIST (National Institute of Standards and Technology) have been looking for candidate algorithms to carry the burden of data protection, undertaking several rounds of selection. However, just as quantum technologies bring cybersecurity threats, they may also give us ways to deal with those dangers.

DO QUANTUM PROBLEMS REQUIRE QUANTUM SOLUTIONS?

Although the breakthrough that has achieved most fame is quantum computing, recent technological advances are not only limited to quantum computers and algorithms. Quantum cryptography is an area that has been in development since the end of the last century and, although it’s also governed by the principles of entanglement and superposition, its way of working and use are more specific than those of a general-purpose quantum computer. In addition, it has the advantage of thwarting quantum cyberattacks.

The most explored quantum cryptography technique is Quantum Key Distribution, or QKD, which is based on the transmission of polarized light pulses in different directions: vertical or horizontal, clockwise or counterclockwise, etc. Each of these directions would translate into either a 0 or 1 bit of a secret key, which we could then use to encrypt our messages with His Majesty.

Due to the quantum properties of light, which do not allow for information to be extracted from systems without disturbing the system, it is possible to detect whether the signal has been covertly intercepted. That is, we’d be able to tell if someone had been a bit nosy, causing the information to collapse before its final interception. If we detect that the key was compromised, we could simply discard it and send another one. We wouldn’t transmit our actual message until we’re able to transmit the key without it being intercepted.

This entire process requires a specialized team. Currently, QKD implementations are carried out in two main ways: via satellite and via fiber optics. Each of these technologies has its pros and cons, but there are now commercial teams implementing them.

RESPONSIBILITY IN THE FACE OF CHANGE

Technological advances open doors to different ways of socializing and seeing life. They allow us to perform tasks in ways that were previously impossible, with both the metaverse and quantum computing entailing a paradigm shift. However, these advances are also a double-edged sword, as they also bring with them certain vulnerabilities. Faced with this dichotomy, it’s important to be aware of the advantages that these changes bring us, but also of their risks. Even more importantly, we must know how to combat those risks.