Zero-knowledge cryptography, also known as zero-knowledge proofs (ZKPs), has emerged from academia into the business world as a solution that could address the pressing issues of data privacy and scalability limits. Led by the University’s Department of Computing Professor Allen Au Manho; and Research Assistant Professor Dr Lu Xingye, the PolyU research team have won the ZPrize in the Plonk-DIZK GPU Acceleration prize category for innovative solutions in empowering zero-knowledge cryptography and was awarded a cash prize of US$550,000.

New technology to improve Plonk’s scalability and efficiency

A major challenge for real-world adoption of ZKPs, particularly for applications at scale, is the high computation cost. In addressing this issue, the PolyU team focused on enhancing the efficiency and scalability of Plonk, a popular ZKP system. The team delivered this achievement by leveraging GPU acceleration to achieve computation speedup and distributing the workload evenly across multiple servers to improve scalability.

Professor Au said, “This is crucial because generating these proofs can be computationally intensive, and so a faster and more efficient method could enable the use of zero-knowledge cryptography in a wider range of applications.”

This new implementation can generate a proof in less than one hour for a circuit of size 2²⁸ gates, which is the largest circuit with reported successful plonk proof generation. The research team’s solution has achieved a significant computation speedup of over 40% on a single machine. With the new distribution approach, the team was able to improve the overall proof generation process by a factor of ten compared with existing method.

Dr Lu added, “Our submission will become open-source libraries for the benefit of the community. We hope this new technology can support the next generation of decentralised protocols and applications to enable secure, interoperable and scalable applications for the next-generation web.”

The Plonk-DIZK GPU Acceleration Prize falls under the open division category of the ZPrize for general public interests. ZPrize is a collaborative effort across the blockchain industry that involves over 32 global partners and sponsors who contribute time, effort and resources to this industry-wide competition, with the aim of increasing the practicality and awareness of this technology.