Will Quantum Computers Disrupt Cryptocurrencies?

Introduction

Regular computers are no match for the strength and speed of quantum computers, which can answer the most difficult equations in a fraction of the time. According to the estimations of some industry specialists, it would just take a few short minutes for them to break an encryption that would take the world's most powerful computers thousands of years to decipher. Because of this, a significant portion of the digital security infrastructure that exists today may be at risk, and this includes the encryption that underpins Bitcoin and other cryptocurrencies.

This article will provide an overview of how quantum computers vary from traditional computers, as well as the dangers they pose to digital infrastructure and cryptocurrency markets.

Asymmetric cryptography and Internet security

Asymmetric cryptography, often known as public-key cryptography, is an essential part of the ecosystem around cryptocurrencies and a significant portion of the Internet's underlying infrastructure. Encryption and decryption of information are accomplished via a key pair, which consists of a public key for encryption and a private key for decryption. In contrast, symmetric key cryptography requires just one key to both encrypt and decode data. Symmetric key cryptography is more secure.

A public key may be widely distributed and used to encrypt information, but the information can only be decrypted by the private key that corresponds to the public key. This makes it so that only the person who is supposed to see the encrypted information can see it.

A significant benefit of asymmetric cryptography is that it enables information to be sent across an untrusted channel without the requirement for the parties involved to first agree upon and then share a shared key. On the Internet, ensuring even the most fundamental level of data confidentiality would have been impossible without this essential capability. For example, it is impossible to imagine online banking without the capability to securely encrypt information that is being sent between parties who are not normally trusted.

Check out the article "Symmetric Encryption vs. Asymmetric Encryption" if you're interested in learning more about this topic.

Some of the security of asymmetric cryptography rests on the premise that the method of creating the key pair makes it exceedingly difficult to calculate the private key from the public key, while it is trivial to compute the public key from the private key. Because it is simple to compute in one direction but difficult to calculate in the other, this kind of function is referred to as a trapdoor function in mathematics.

At the moment, the vast majority of contemporary algorithms utilized to produce the key pair are based on well-established mathematical trapdoor functions. It is unknown whether these trapdoor functions can be solved in a timescale that would be realistic for any machine currently in existence. Even the most sophisticated computers would need significant time to complete these calculations.

Nevertheless, this might soon change as a result of the development of new types of computing systems known as quantum computers. First, let's look at traditional computers' operation so we may see why quantum computers are so much more powerful.

Classical computers

Classical computers are another name for the kinds of computers that are used nowadays. This indicates that computations are done in a sequential manner—a computing job is accomplished, and then another one may be begun. This is because the memory of a classical computer is constrained by the rules of physics and can only be in one of two states: either 0 or 1. (off or on).

Many different hardware and software approaches may be used to enable computers to partition complicated calculations into more manageable portions to improve their overall efficiency. Nevertheless, the fundamentals have not changed. Before moving on to the next computational endeavor, the previous one has to be finished first.

Consider the following scenario, in which a computer is tasked with attempting to guess a 4-bit key: Each of the four bits has the potential to be either a 0 or a 1, respectively. Sixteen different permutations might occur.

In order to solve a problem, a traditional computer would have to try each possible combination in turn, one after the other. Imagine that you have a keychain with a lock and 16 keys on it. It is necessary to test every one of the 16 keys on their own. If the first one doesn't work, you may try the next one, then the next one, and so on until you find the one that does. This continues until you find the key that works.

The number of feasible combinations, on the other hand, increases at an exponential rate in proportion to the key length. In the preceding example, if we added one more bit to bring the total number of bits in the key to 5, we would end up with 32 different potential combinations. Bringing it up to 6 bits would bring the total number of viable possibilities to 64. When using 256 bits, the number of potential combinations approaches the number of atoms that are thought to exist in the observable universe.

In contrast, the speed at which computers process data can only increase linearly. The number of guesses that may be made in a given amount of time is only increased by a factor of two whenever the processing speed of a computer is increased by a factor of two. On the side of guessing, exponential growth is much faster than linear growth by a large amount.

It is projected that it would take millennia for a traditional computer machine to guess a key that is 55 bits in length successfully. As a point of comparison, the recommended minimum size for a seed used in Bitcoin is 128 bits, but many wallets use 256 bits instead.

Asymmetric encryption, which is used by cryptocurrencies and is the backbone of the internet, seems to be safe from traditional computing.

Quantum computers

Quantum computers are still in the very early phases of development, but once they are perfected, it will be a piece of cake to resolve the aforementioned categories of issues with them. The theory of quantum mechanics, which looks at how subatomic particles behave, is the basis for quantum computers because it tells us how they should work.