Reducing the Share Size of Weighted Threshold Secret Sharing Schemes via Chow Parameters Approximation

A cargo del Miquel Guiot.

A secret sharing scheme is a cryptographic primitive that allows a dealer to share a secret among a set of parties, so that only authorized subsets of them can recover it. The access structure of the scheme is the family of authorized subsets. In weighted threshold access structures, each party has a weight, and subsets are authorized if their combined weight reaches a threshold. For these access structures, existing secret sharing schemes result in large shares that scale linearly with the weights. To improve efficiency, the access structure can be approximated. This talk focuses on balancing efficiency and accuracy in such approximations by using techniques based on the Chow parameters. This is a joint work with Oriol Farràs and will be presented in Theory of Cryptography Conference (TCC) 2024.