IN BRIEF:
Quantum computing, which uses subatomic particles to create new ways of processing and storing information, promises to be the future of computing. Operating orders of magnitude faster than the best processors available today, the technology will help solve complex problems in a fraction of the time.
With this in perspective, it is possible to draw a parallel between Quantum Computing, AI and Blockchain to understand the differences and possible causes of the vulnerabilities caused by the former, as well as possible synergies.
But in order to understand the impacts of the emergence of Quantum Computing on other technologies, we need to understand some basic concepts.
How did Quantum Computing come about?
In the early 1980s, Richard Feynman, Paul Benioff and Yuri Manin provided the foundations for a completely new paradigm, introducing the idea that Quantum Computing had the potential to solve problems that "classical computing" could not.
The computing power of this technology comes from "entanglement". This happens when two particles are entangled - entanglement causes two particles to remain in the same state. If one changes, the other can also change, depending on the state of the other.
The distance between them doesn't matter, and each will reflect the state of the other particle. This is what makes computer scientists excited about quantum computing. At the moment, companies are working hard to increase the number of qubits.
What are quibits?
Qubits are the basic units of information used by quantum computers. Unlike ordinary bits, which store data as 1s or 0s, qubits take advantage of the quantum phenomenon known as superposition. This means that they essentially exist as 1s and 0s simultaneously.
The advantage of this phenomenon in computing is that it exponentially increases the amount of information that can be processed. A pair of qubits, which can exist as 1s or 0s, can incorporate four possible states. Three qubits can incorporate eight. But three hundred qubits can incorporate more states than the number of atoms in the Universe.
The qubit journey began in 1998, when Oxford, MIT, IBM and others managed to work with just two qubits. Today, the limit has reached 72 qubits.
How did quantum technology grow?
After Richard Feynman, Paul Benioff and Yuri Manin introduced the idea of quantum computing in 1994, Peter Shor, currently at the Massachusetts Institute of Technology, found the first example of a quantum algorithm that could dramatically speed up the solution of a practical problem. This algorithm was able to efficiently solve problems in cryptography that are difficult for classical computers to solve.
To this day, the algorithm created by Shor continues to threaten the foundations of most cryptography deployed around the world. The problem was that, in 1994, there was no quantum computer in sight.
It wasn't until 1997 that the first tiny quantum computer was built.
But the field only really took off when Canadian start-up D-Wave unveiled its 28-qubit quantum computer in 2007.
Similar to the trajectory of non-quantum communication, which took more than 100 years from discovery to the mainstream, quantum computers are in the process of maturing.
To give you an idea, in 2019, CES unveiled the IBM Q System One: a 20-qubit quantum computer built to be stable, which caused quite a stir due to its beautiful design.
In 2021, in a blog post, Google said it aims to build a "useful, error-correcting quantum computer" by 2029, after claiming quantum supremacy in 2019.
Despite all the investment in quantum technology - as we'll see later - the future of Quantum Computing is still far from a reality.
Global efforts and market projections up to 2040
Today, many players are vying to build the first powerful quantum computer. This includes commercial entities such as IonQ, Rigetti, IBM, Google, Alibaba, Microsoft and Intel. See Fig.3 for 20 years of quantum computing growth.
Similarly, the world's leading economies are investing billions of dollars in the development and research of Quantum Computing. See Fig.4 for the global quantum effort by country.
According to a McKinsey report published in 2023, the global quantum effort leading to research and innovation in quantum science and technology is steadily increasing, with current worldwide investments exceeding US$38.6 billion. And the projection for the global quantum technology market is $106 billion by 2040.
Quantum computers are powerful, but difficult to build. So whoever gets there first will have a powerful and lasting advantage.
No wonder important organizations are pooling their expertise in the quest to master this technology. To give you an idea, the paper "Quantum-enhanced greedy combinatorial optimization solver" is the result of the collaborative effort of a program launched by DARPA in 2019 known as Optimization with Noisy Intermediate Scale Quantum (ONISQ).
ONISQ was created to promote a close scientific partnership between NASA, the Universities Space Research Association (USRA) and Riggetti Computing. Its main objective is to develop pioneering quantum optimization methodologies to strengthen future US military capabilities
In terms of technology, where are we now?
Considering the immense challenges of building quantum computers, we are more or less where we were around 1970 with classical computers.
We have some, but they are still unreliable compared to today's standard. What do I mean by that? Today's quantum computers work, and there are even some available for anyone to program. IBM, Rigetti, Google and IonQ provide public access with open source tools for real quantum computing hardware.
However, they are still very poor and intermediate scale because of their small number of qubits. In short, quantum computers are still being worked on, but are not yet a reality.
Challenges to overcome in creating a quantum computer
The benefits of quantum computers bring extraordinary advantages, but are equally difficult to maintain. The superposition state produces performance, but it is not stable. To make them stable and manage them, physicists apply many methods - including microwave or laser beams -, need to control the temperature and ensure that there is no interaction of any kind with the working environment.
With this low resistance to the environment, quantum computers are difficult to maintain. A small difference in one of the elements can jeopardize the entire operation. The process by which dissipation occurs is known as "decoherence".
In short, the more stable the qubits, the more computing power is generated. However, as we increase the number of qubits, the environment becomes more unstable and difficult to control.
At the moment, the most important applications of quantum computing concern the behavior of matter, chemistry and the discovery of materials. But it will take time to understand how we can extend its usefulness.
At the current stage of development, our capacity is too limited to imagine the applications in the near future.
Could quantum computing threaten blockchain?
Blockchain technology is known for its security. According to a report by Deloitte, more than 84% of companies expect blockchain to offer more security than conventional IT systems. Its unique features make it a great candidate for protecting any business system.
Note that its security comes from three main factors:
Well, a blockchain network works based on the idea of nodes interconnected peer-to-peer, without a central server (decentralization), which transfer encrypted information (cryptography) to each other and are able to "make decisions" and reach an "agreement" through a consensus mechanism (game theory).
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As I've already covered here, it's consensus algorithms, decentralization and cryptography that ensure that the entire blockchain network is resistant to counterfeiting.
However, this doesn't mean that the blockchain can't be hacked.
When a blockchain doesn't use a good consensus algorithm, i.e. when the game theory design isn't well thought out, it can suffer a 51% attack.
One of the most popular ways of hacking a blockchain network is for the attacker to take control of 51% of the nodes - known as the 51% attack.
By doing this, the cybercriminal can confirm fake transactions across the network, double-spend and steal lots of information or cryptocurrencies.
Other different types of cyber attacks on blockchain networks include:
One blockchain that has always been able to defend itself, despite suffering hundreds of daily attempts to attack its consensus algorithm - whether through the 51%, the Sybil attack or the DDoS attack - is the Bitcoin protocol. But can it fail when quantum computing enters the picture?
Unidirectional functions and the lack of quantum-proof "cryptographic algorithms" or "consensus algorithms" are the two possible causes of blockchain vulnerability.
1 - One-way mathematical functions
Today's computers are capable of generating digital signatures for security purposes, but obtaining the key or reversing it is completely impossible. In other words, the current generation of blockchain uses one-way mathematical functions.
For a conventional computer, it is easy to compute them in one direction, but impossible to do so in the opposite direction. This makes the use of these unidirectional mathematical functions very useful.
Since nothing beats an example to understand something, let's think about prime numbers. You can multiply prime numbers efficiently, but if you want to find the prime factors of two products of prime numbers, this will be difficult.
This dual nature of mathematics makes it easier to generate digital signatures for blockchain, and then it can be used for authentication purposes.But from a hacker's point of view, this means reversing the equation, which is practically impossible to do with today's computers.
Furthermore, such one-way functions are efficient for generating hash functions that can be used to verify newly added blocks to a ledger. But if the content of the hash function is modified by a cybercriminal, the hash value will not match the modified content, and the block information will be discarded by the network.
Thus, the only way for a cyber attack in this case would be to find the hash value of a block - which would require reversing the function.
Now, assuming that today's computers are capable of solving trillions of keys per second, they would need to perform 785 million calculations to find the hash value of a block - which would take 14 billion years.
With quantum computing, however, this scenario will change, because quantum computers will be able to perform multidirectional mathematical functions in zillions of seconds.
2 - Lack of quantum-proof cryptographic algorithms
As current cryptographic algorithms or consensus algorithms only take into account current computing power, there is a clear lack of quantum-proof cryptographic algorithms used in most blockchain solutions.
However, as every rule has exceptions, NEO is a blockchain that has been developing quantum-proof algorithms since 2018. Their approach is to build for the future and choose algorithms that can support the enormous power of Quantum Computing when it arrives.
Perspectives on the interrelationship between Blockchain and Quantum Computers
I've already commented here that we're heading towards the Convergence Era, where all the General Purpose Technologies [GPT] leverage each other, taking us into an era of exponential evolution never seen before.
And as general-purpose technologies - just like the internet and electricity -, Blockchain and Quantum computing also have synergies.
How could quantum computers improve Blockchains?
Quantum technology could be a game changer in solving the blockchain trilemma:
⎯ Improving security through the use of quantum networks
Quantum networks are very secure channels where you exchange qubits with each other. Unlike classical computer networks, a quantum network instantly detects any attempt to breach the system, guaranteeing the security of communication.
⎯ Improved scalability through interlacing.
By taking advantage of entanglement - which is where the computational power of quantum computing comes from - the scalability and decentralization of the blockchain can be enhanced.
With quantum computing, we can have more nodes. Quantum technology adapts very well to a power of two for the number of nodes. And so we can improve decentralization by increasing the number of nodes made possible by quantum.
Finally, the increased scalability made possible by quantum technology can allow blockchains to handle large volumes of data by design, facilitating consensus on a larger scale.
How do AI, quantum computing and blockchain intersect?
⎯The intersection between AI and Quantum computing
Since AI relies heavily on data - as I've explored here - the enormous processing power of quantum computers could give AI the boost it needs to become even smarter and faster. In other words, quantum computing could be like a super-trainer for AI. In other words, quantum computing could be like a super-trainer for AI, helping it to learn and grow at an unprecedented rate.
Now, let's include blockchain in the game.
⎯ Mixing AI, Quantum Computing and Blockchain
The strength of blockchain lies in its security and transparency. Every transaction is recorded and can be traced, which makes it incredibly difficult for anyone to circumvent the system. But this security comes at a cost: speed. Quantum computing, with its ability to process data at the speed of light, could help solve this problem by making the blockchain faster without sacrificing security.
AI could use the secure environment of the blockchain to operate, with quantum computing speeding up both processes.
It could lead to a future where AI can make safe, fast and effective decisions, from managing your finances to diagnosing illnesses.
Final thoughts
We live in an Information Age in which everything is possible.
The concept of cyber security varies from time to time. Looking back through history, we would never have imagined that the enigma code could be deciphered.
In this context, and considering that blockchain technology is only 15 years old, it is very likely that solutions suitable for Quantum Computing will be developed and implemented on current blockchains.
Similarly, Quantum Computing is in its infancy and will require a major effort from governments and companies to become a reality.
But what about you? Did you understand that the "post-quantum AI Blockchain" scenario has yet to be defined? Did you have any idea that when quantum computers become a reality, they will definitely impact the way we protect our systems?
Not just blockchain networks, but any system that uses cryptography - such as apps from financial institutions, government platforms, among others - will be affected.
