Researchers propose quantum proof-of-work consensus for blockchain

A team of researchers from universities in Australia and the United States, working in collaboration with quantum technology company BTQ, recently published research proposing a new proof-of-work (PoW) scheme for blockchain consensus that relies on quantum computing techniques to validate consensus.

Called “Proof-of-work consensus by quantum sampling,” the preprint research paper describes a system that the authors claim “provides dramatic speed and energy savings over computation with classical hardware.”

According to the researchers, current algorithms for solving PoW consensus tasks are slow and require a significant amount of computational resources to process:

“While classical PoW schemes such as Bitcoins are notoriously energy-inefficient, our boson sampling-based PoW scheme offers a far more energy-efficient alternative when implemented on quantum hardware.”

According to the paper, the quantum advantage offered by this scheme will also increase the difficulty of mining, thus making it possible to “maintain consistent block mining time” as the number of miners increases, further incentivizing the continued participation of “quantum miners.”

The sampling process the researchers refer to, boson sampling, is not new, but its application to blockchain technology seems novel. Boson sampling has shown promise in a number of quantum computing applications. Yet, as a non-universal quantum computing solution (it must be used in a system built for a specific task), its potential has been limited to a few select domains, such as chemistry.

Related: How does quantum computing affect the financial industry?

However, according to the researchers, it could be the perfect solution to future-proof blockchain applications and potentially reduce the environmental impact of mining on the Bitcoin blockchain and similar chains.

Apart from quantum advantage, quantum hardware also has a leg up on old school computers because of how blockchain mining works.

One of the current advantages of classical supercomputers over their new quantum cousins ​​is the ability to “precompute” when dealing with the same class of problems regularly. But in the case of blockchain, such precomputation is essentially a waste.

Mining is, as the researchers put it, a problem that is “free of progress”. No matter how many times a blockchain puzzle is solved to provide proof of work, the computer and algorithms that process the challenges never get better at solving the problem.

This means that quantum computers, despite being notoriously challenging to develop and expensive to build and maintain, will eventually be able to validate consensus more efficiently than state-of-the-art classical systems.