For a brief moment of time in September (2019), certain segments of the cryptocurrency community were up in arms over worries that Google had created a supercomputer more than capable of breaking Bitcoin and its underlying code. The worries were birthed from a since deleted post that appeared on the NASA website.
If you have heard about Google's supercomputing power and you are worried about it, this post aims to set the record straight. Quantum computing is no threat to Bitcoin, at least for now. It probably never will be. Cryptocurrency security experts will undoubtedly develop their own technologies to keep pace with quantum computing.
Having said that, it is worthwhile exploring quantum computing and its possible effect on cryptocurrency. By understanding the potential that quantum computing holds, we should be better prepared to use it to cryptocurrency's advantage rather than running scared as though quantum computing is some monster not to be set free.
How traditional computers work
Understanding quantum computing starts with an understanding of how traditional computers work. Traditional computers are little more than advanced calculators capable of dealing with all sorts of data represented by the digits 0 and 1. Their operation is simple in principle, though sometimes complex in practice.
In order to make use of data, computers must see that data represented as zeros and ones. The numbers represent actions comparable to a mechanical light switch. A zero would dictate flipping the switch to the 'on' position while a one would dictate flipping it to the 'off' position.
By flipping the switches on and off, traditional computers are able to complete mathematical computations. The results of said computations determine what the computer does with the data. It matters not whether you are talking about a video game or an office suite; they all run on binary data consisting of zeros and ones.
As you might expect, such a basic way of handling computations naturally limits the abilities of traditional computers. The more complex a piece of software is, the more complex the data it is working with. That complexity increases the workload required to complete tasks within the software. The heavier the workload, the more resources required.
It is possible to create computations for which traditional computers lack the resources to solve. These are considered unsolvable problems. The problems do have solutions in theory, it is just that the computers do not have enough resources to do the work. It is believed that quantum computing might be the solution to such limits.
How quantum computers work
Quantum computing is based on the idea of using small pieces of binary data, known as bits, to facilitate computations. Traditional computers use bits as well. What makes the two computing models different is how and where those bits exist within the computational space.
A good way to illustrate the difference is to imagine a globe you might have used in school during your geography lessons. The bits used by standard computers would be represented by the two poles. Those two poles are fixed. The North Pole is always in the same location, as is the South Pole.
The bits utilized in quantum computing, known as qubits, are not locked into a single position. They can be located anywhere across the globe. Moreover, they can be moved around to different positions as needed. This affords the quantum computing model the ability to store a lot more information in a limited amount of space and, subsequently, complete more computations with fewer resources.
The globe example is an oversimplification of something that occurs at the atomic level. Success in the quantum computing world rests in understanding how things behave at that level. Unfortunately, particles do not always behave in predictable ways when you are talking atomic and subatomic. As such, quantum computing is not nearly as easy to manage as standard computing. Therein lies the problem.
The perceived threat to Bitcoin
This post will go on to explain why quantum computing is no threat to Bitcoin for the time being. But first, let us talk about the threat itself. What are people worried about? Why would anyone be concerned that Google created a supercomputer capable of breaking Bitcoin?
The alleged threat to Bitcoin from quantum computing can be encapsulated in a single word: speed. Let's assume the deleted post that started this whole thing turned out to be accurate. It would mean Google possesses a supercomputer capable of doing in 200 seconds what it would take traditional computers 10,000 years to do. The speed differential is almost unimaginable.
Such capabilities could be a problem for Bitcoin due to the amount of time it takes to process a transaction and the amount of resources necessary to do it. Both play into what makes Bitcoin a secure cryptocurrency platform.
How transactions are processed
Every Bitcoin transaction is represented on the network with two addresses (the sender's and recipient's) and a rather extensive set of alphanumeric data. That alphanumeric data is used by coin mining computers to solve complex mathematical equations. The equations get more complex with every new transaction processed.
Every mining computer processing transactions and building new blocks is competing to be the first one to complete the block in the chain. The winner is rewarded in coin. However, winning the race is not easy. It takes a lot of time and electricity to create a single block thanks to all of the mathematical computations mining computers have to perform.
Mining computers essentially have to guess at the value of each alphanumeric character. Then those values must be run through a computation to arrive at a specific answer. All of the mining computers on the network must arrive at same answer for a transaction to be finalized.
The complexity of the system helps to maintain network security. And because so much computational power is necessary just to compete as a coin miner, it is nearly impossible for any one entity to crack the system and take over. The computational resources are just not there to do it.
Quantum computing capability
The threat of quantum computing comes from its speed. Being able to work so much faster and with fewer resources theoretically gives the quantum model the ability to crack Bitcoin's encryption. Not only that, quantum computing could theoretically crack the encryption in seconds. Anyone with a supercomputer capable of hacking Bitcoin could get in, steal every single coin, and get out before anyone knew what happened.
One must remember that any technology that could be used against Bitcoin could also be used to its advantage. This is the primary reason quantum computing will probably never be an existential threat to Bitcoin or other cryptocurrencies.
Development alongside quantum computing
It has been estimated that Google's current quantum computing capabilities are limited to 53 qubits. In order for them to build a machine capable of threatening Bitcoin, they would have to be somewhere in the neighborhood of 1500 qubits. Not only that, computer software capable of untangling the intricate web of Bitcoin transactions would also be necessary.
You can bet that cryptocurrency developers are already aware of Google's current quantum computing capabilities. You can also bet they are not ignoring such capabilities. They are keeping a close eye on Google while also exploring quantum computing for their own needs.
Imagine the same power that would allow a supercomputer to crack Bitcoin being used to improve the platform. That kind of computing power would allow Bitcoin to compete with chief rivals like Visa and MasterCard. Transaction speeds would be nearly instantaneous, and mining would suddenly become popular again.
New security models
Of course, accommodating quantum computing without compromising security will require cryptocurrency developers to come up with new security models. That is only logical. To believe they would ignore the threats of quantum computing and fail to produce said models is ludicrous.
New security models will somehow have to account for the speed of quantum computing. They will have to account for the fact that future supercomputers will be able to run many more calculations while using fewer resources. There is little doubt that developers will do so. They will have access to the same technologies as supercomputer builders.
If you are a participant in the cryptocurrency economy, do not take the potential of quantum computing as a threat to Bitcoin. Rather, understand that it has just as much potential to make cryptocurrency better. Greater speed means more transactions every second. Fewer resource requirements means more mining capabilities. It all points to greater acceptance the world over.
Quantum computing could very well be the tool that makes it possible for cryptocurrency to replace fiat completely. That is not to say that countries will not have their own national currencies, just that those currencies are likely to be entirely digital at some point in the future.
As we wait for that day to arrive, the technology world will be keeping an eye on Google and its supercomputing capabilities. Will Google be the first one to reach the 1500 qubit threshold? If not, will it be one of their current rivals that beats them to the finish line? Only time will tell. It will be an interesting race to watch, if nothing else.