Prof. Sherman S. M. Chow has received the Test of Time Award at the 31st ACM Symposium on Access Control Models and Technologies (SACMAT 2026), held from 8 to 10 July 2026 in Waterloo, Canada. SACMAT is the premier forum dedicated to access control research, spanning models, systems, applications, and theory.

Established in 2018, the award recognizes research that has had a lasting impact on the field. Prof. Chow is the first scholar to receive this award while based at an Asian institution, bringing the honor to Hong Kong.

The award recognizes his sole-authored 2016 paper, which he wrote while at CUHK and published in the proceedings of SACMAT 2016. In its announcement, SACMAT described the paper as foundational and highlighted its sustained influence on access control research over the past decade.

Attribute-based encryption enables fine-grained access control over encrypted data by allowing decryption rights to be specified in terms of user attributes. The paper presented a generic framework for constructing multi-authority attribute-based encryption with attribute revocation and outsourced decryption. Rather than relying on a tailor-made number-theoretic construction, the framework can be instantiated from any pairing-based single-authority attribute-based encryption scheme satisfying a set of identified properties.

At the award presentation, he delivered a retrospective on the origins of the work, its subsequent influence, and the research directions that remain open. The occasion held particular personal significance because he began his research career as a research fellow at the University of Waterloo, the host institution of this year’s symposium.

Hearty congratulations to Prof. Chow on this distinguished achievement.