Paper 2025/631

Dyna-hinTS: Silent Threshold Signatures for Dynamic Committees

Abstract

The works of Garg et al. [S&P'24] (aka hinTS) and Das et al. [CCS'23] introduced the notion of silent threshold signatures (STS) - where a set of signers silently perform local computation to generate a public verification key. To sign a message, any set of $t$ signers sign the message non-interactively and these are aggregated into a constant-sized signature. This paradigm avoids performing expensive Distributed Key Generation procedure for each set of signers while keeping the public verification key constant-sized. In this work, we propose the notion of committee-based silent threshold signature (c-STS) scheme. In a c-STS scheme, a set of signers initially perform a one-time setup to generate the verification key, and then a subset of signers are randomly chosen for an epoch to perform the threshold signing while the other signers are not authorized to sign during that epoch. This captures existing systems like Ethereum Altair and Dfinity where only a specific committee is authorized to sign in a designated epoch. The existing STS schemes cannot be extended to the committee setting because the signature verification only attests to the number of signing parties, not which committee they belong to. So, we upgrade hinTS to the committee setting by proposing Dyna-hinTS. It is the $$ c-STS scheme and it requires a one-time silent setup and generates a one-time public verification key that does not vary with the committee. Assuming a set of 1024 signers (with corrupt 682 signers), hinTS generates an aggregated signature in 1.7s whereas Dyna-hinTS generates it in $$s within a committee of $$ signers. This yields a $$ improvement over hinTS for signature generation at the cost of increasing signature verification time by $$ over hinTS. Dyna-hinTS supports general access structure, weighted signatures and improves existing multiverse threshold signatures.