Scientists propose quantum proof-of-work consensus for blockchain

Boson sampling was previously seen as a problem in need of a solution, but now it has the potential to serve as a link between quantum computing and blockchain technology. A group of researchers from Australian and American universities, in collaboration with the quantum technology company BTQ, recently published a research paper introducing a unique proof-of-work (PoW) mechanism for blockchain consensus. This novel approach utilizes quantum computing techniques to validate consensus and is called “Proof-of-work consensus by quantum sampling.”

The preprint research paper outlines a system that offers significant speedup and energy savings compared to classical hardware computation. The researchers assert that existing algorithms for solving PoW consensus puzzles are slow and demand substantial computational resources. In contrast, their boson sampling-based PoW scheme provides a more energy-efficient alternative when implemented on quantum hardware.

According to the researchers, this scheme’s quantum advantage would also increase mining difficulty, allowing for consistent block mining time even with an expanding number of miners. This incentivizes ongoing participation by “quantum miners.”

Although boson sampling is not a new process, its application to blockchain technology appears to be innovative. Boson sampling has shown promise in various quantum computing applications but has been limited to specific domains, such as chemistry, due to its non-universal nature. However, the researchers propose that it could be the ideal solution for future-proofing blockchain applications and potentially reducing the environmental impact of mining on blockchains like Bitcoin.

In addition to quantum advantage, quantum hardware has an edge over traditional computers concerning the nature of blockchain mining. Classical supercomputers can “precompute” solutions for specific recurring problems, giving them an advantage. However, in the context of blockchain, such precomputation is essentially useless.

Mining is a “progress-free” problem, as stated by the researchers. Regardless of how many times a blockchain puzzle is solved to provide proof-of-work, the computer and algorithms involved do not improve at solving the problem. Consequently, despite the challenges and expenses associated with developing and maintaining quantum computers, they would ultimately be more efficient than state-of-the-art classical systems in validating consensus for blockchain applications.

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