This content originally appeared on DEV Community and was authored by jack jack
Quantum computers are powerful machines that can solve very complex equations much faster than ordinary computers. The speed of these computers is such that some experts believe that breaking the cryptography that takes thousands of years with today's computers with the help of quantum computers will take only a few minutes. As a result, much of today's digital security infrastructure could be compromised. This includes cryptocurrencies and bitcoins.
You can read more about the differences between quantum computers and conventional computers and their dangers for digital currencies and digital infrastructure.
Asymmetric encryption and Internet security
Asymmetric cryptography, or public-key cryptography, is an essential component of the cryptographic ecosystem and major Internet infrastructure. This method relies on a key pair to encrypt and decrypt information—a public key for encryption and a private key for decryption. In contrast, symmetric key encryption uses only one key to encrypt and decrypt data.
An unrestricted, public key can be shared and used to encrypt information. This encrypted information will only be decrypted with the corresponding private key. In such cases, you can be sure that only the intended recipient can access the encrypted data.
One of the main advantages of asymmetric encryption is exchanging information without having to share a shared key in an unreliable channel. Without this vital capability, it is impossible to maintain basic information on the Internet. Imagine online banking without the ability to encrypt communication between parties securely. In such cases, anyone can access the person's account only by having the card number.
Part of asymmetric cryptographic security is based on the assumption that the critical pair generating algorithm makes it extremely difficult to identify and build a private key from a public key while placing a public key from a private key is very simple. This function is called a trapdoor in mathematics because it is easy to calculate in one direction but complex in the other.
Most modern algorithms used to generate key pairs (public and private keys) are based on trapdoor functions. Trapdoor functions are known to be challenging to decode. It is challenging for existing computers to crack these passwords. Performing these calculations and decoding is considerably time-consuming, even for the most powerful machines.
However, things may soon change with the development of new computing systems known as quantum computers. To understand why quantum computers are so powerful, let's first look at how ordinary computers work.
Classic or ordinary computers
The computers we deal with today can be called classic computers. This means that computational tasks in this type of computer are performed sequentially; First, a computational study is conducted and completed, then another study can be started. This is because the memory in a classic computer must follow the physics laws and can only have a state of 0 or 1.
Various hardware and software methods allow computers to break down complex computations into smaller parts, thus improving efficiency. However, the basis of computer work is not much different. One computational task must be completed before another can be started.
To understand more, consider the following example:
This is where the computer is supposed to guess a 4-bit key. Every 4 bits can be 0 or 1. As shown in the table, there are 16 possible combinations:
A classical computer must guess each combination separately. Imagine you have a lock and 16 keys on a keychain. Each of the 16 keys must be tested independently. If the first key does not unlock, you can go to the following key and try the next key to open it.
As the length of the critical string increases, the number of possible compounds grows exponentially. In the example above, adding an extra bit to increase the necessary string length to 5 bits results in 32 possible combinations. Raising it to 6 bits results in 64 possible combinations. At 256 bits, the number of potential compounds is close to the estimated number of atoms worldwide.
Computational processing speed, on the other hand, grows only linearly. Doubling a computer's processing speed will only double the number of guesses made at a given time. Exponential growth will far outweigh any linear progression in guessing.
Therefore, it is said that a classical computing system takes thousands of years to guess a 55-bit key. While the minimum recommended size for a bitcoin core is 128 bits, wallets have implemented 256 bits.
Traditional computing does not seem to threaten asymmetric encryption, so digital currencies and the Internet infrastructure are safe from classical computing.
Quantum Computers
At present, there is a group of computers in the early stages of development that will be very advanced to solve such problems. These computers are known as quantum computers. Quantum computers are based on the fundamental principles described in the theory of quantum mechanics, which deal with how subatomic particles behave.
In classical computers, a bit is used to represent data. A bit can have a state of 0 or 1. Quantum computers work with quantum bits or qubits. Just like a bit, a qubit can have a form of 0 or 1. But thanks to the properties of quantum mechanical phenomena, the qubit state can be both 0 and 1 simultaneously.
This has given rise to many incentives for research and development in quantum computing. Both universities and private companies are spending time and money trying to discover the hidden points of this new and exciting field.
However, one of the problems with quantum computers is that they solve and decrypt algorithms based on asymmetric cryptography.
Consider the example of breaking a 4-bit key again. A 4 qubit computer is theoretically capable of performing all 16 modes (combinations) simultaneously with a computational task. As a result, the correct key will be found 100% in the same study at a given time for these calculations.
Quantum resistant cryptography
The advent of quantum computing technology could weaken cryptography, the foundation of most modern digital infrastructure, including cryptocurrencies.
This can overshadow various sectors of which the world's security, operational, and communications sectors are only a part. From governments and multinational corporations to the average user may be affected. Not surprisingly, a significant amount of research is spent on research and development and interaction with this technology. Those cryptographic algorithms that are thought to be safe from the threat of quantum computers are called quantum-resistant algorithms.
At present, various ways and methods have been proposed, such as simply increasing the length of the critical string with symmetric encryption, which may cause many other problems due to the emergence of standard keys. However, this problem can be solved with the help of quantum cryptography itself. Advances have also been made in this direction to prevent the creation of identical keys using quantum computers. It is now possible to determine if the asymmetric key has already been read or manipulated by a third party.
There are other ways to investigate possible attacks based on quantum computers. These can include basic techniques such as hashing to create large-scale messages or other methods such as network encryption or standard network-based encryption. All this research aims to develop a type of encryption that is difficult for quantum computers to break.
Quantum computers and bitcoin mining
Bitcoin mining also uses cryptography. Miners compete for block rewards to solve a cryptographic puzzle. If a miner has access to a quantum computer, he may dominate the entire network. This can reduce network decentralization and potentially expose the network to a 51% attack.
However, according to some experts, this is not a threat that will affect Bitcoin quickly. ASIC devices can reduce the impact of such attacks, at least in the short term. Also, if multiple miners have access to quantum computers, the attack risk is significantly reduced by 51%.
Concluding remarks
The threat of quantum computing development for the implementation of the current asymmetric encryption system seems very serious. However, it should not be forgotten that this threat is not very close, and many substantial theoretical and engineering obstacles must be solved before it can be fully realized.
Given the great dangers of information security, it makes sense to prepare for possible future attacks. Fortunately, a great deal of research has been done on potential solutions implemented in existing systems. These solutions could theoretically protect our critical infrastructure against the threat of quantum computers in the future.
Quantum-resistant standards can be distributed to the general public in the same way that end-to-end encryption is performed through popular browsers and messenger applications. Once these standards are finalized and implemented, the cryptocurrency ecosystem can easily integrate the most potent form of defense possible against this attack.
This content originally appeared on DEV Community and was authored by jack jack
jack jack | Sciencx (2021-10-22T15:12:29+00:00) How Do Quantum Computers Challenge the Future of Cryptography?. Retrieved from https://www.scien.cx/2021/10/22/how-do-quantum-computers-challenge-the-future-of-cryptography/
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