What will happen to Bitcoin when quantum computing is developed? This is one of those questions on the minds of many people, usually heard in events and Blockchain sessions. It’s an **honest question.**

The entire Blockchain system is based on the computational capacity of the miners and the hash rate. If a new technology appears capable of multiplying this computational capacity, it can be a great threat. Could the famous 51% attack be given if someone has enough computing power?

I leave you an answer from years ago by the great Andreas Antanopoulos to a similar question:

Following the same logic, what would happen if someone uses quantum computing to do this attack? that it would have a 10 minutes advantage until the next block is mined and the attack reverted? Well, that **doesn’t sound like a great idea.** And since there are not many quantum computers, perhaps it would be relatively easy to know who it was…

What if instead of hacking the network he dedicated himself to mining and receiving a fair reward for his effort? What if your reward was legal and honest and you didn’t have to worry about its traceability and anonymity?

But there is an important variable that we have not taken into account.

**Quantum computing has an important advantage, which is energy savings.**

There is a lot of talk about “quantum supremacy”, based on raw computing power: we want to compute much faster.

In the future, a quantum computer will be able to solve problems in a few hours, while a supercomputer could take several tens of billions of years. That would mean a great energy saving 😉 But we are still very far from this scenario.

A more realistic approach that is already being carried out is to create less powerful quantum computers, capable of solving calculations in a time relatively comparable to that of supercomputers, but consuming much less energy. Interesting approach to the crypto world.

**Google’s Sycamore quantum processor consumes just 26 kilowatts** of electrical power. Much less than a supercomputer. It can run a test quantum algorithm in seconds.

The problem with quantum computers is **superposition**. A bit can be 1 or 0, while a Qbit in a quantum computer can be 1, 0 or either (it can be several numbers at the same time) which leads to a problem called superposition. This superposition is resolved, it is destroyed, when for example the Qbit receives a photon (a particle of light) that fixes this value between 0 and 1. For those who like to investigate further, this process is called **Decoherence**.

But the important thing here is that to prevent these photons from destroying this superposition and our Qbits from free dancing we need to protect them with a temperature of **-273 ºC.** This is the highest energy cost of quantum computing. But it costs almost the same to maintain this temperature for 300 Qbits, than for 3,000. In other words, the scalability is brutal while the relative energy cost is very low, especially if we compare it with traditional computing.

**In other words, quantum computing, far from being a threat to Bitcoin, could be the solution to what many consider to be its main weakness, energy consumption.**

Let bitcoin be quantum

**Yours in crypto**