Scientists propose quantum proof-of-work consensus for blockchain

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

Our new paper on using NISQ-era quantum sampling problems in proof-of-work blockchain consensus algorithms. In association with @BTQ_Tech.

— Peter Rohde (@drpeterrohde) June 1, 2023

Dubbed “Proof-of-Work Consensus by Quantum Sampling,” the preprint research paper describes a system that the authors claim offers “dramatic acceleration and energy savings compared to computation by classical hardware.”

According to the researchers, current algorithms for solving PoW consensus puzzles are slow and require a significant amount of computing power to process:

“While classical PoW schemes like Bitcoin’s are notoriously energy inefficient, our boson sampling based PoW scheme offers a much more energy efficient alternative when implemented on quantum hardware.”

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

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

Related: How will quantum computing affect the financial sector?

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.

Aside from the quantum advantage, quantum hardware also has an edge over old school computers due to the nature of how blockchain mining works.

One of the current advantages of classical supercomputers over their new quantum cousins ​​is the ability to “pre-compute” when dealing with the same types of problems on a regular basis. But when it comes to blockchain, such precompute is essentially wasted.

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

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