cronokirby

(2026-04) Oriole; Adaptively Secure Partially Non-Interactive Threshold Signatures from Lattices

2026-04-22

Abstract

We present the first lattice-based, partially non-interactive threshold signature scheme that tolerates the adaptive corruption of up to T1T-1 signers, where TT is the signing threshold. Our construction relies on the MSIS and MLWE assumptions, and has two rounds, of which only the second is message-dependent. We substantially improve upon prior adaptively secure lattice-based schemes (CRYPTO '24 and EUROCRYPT '26), which require at least two message-dependent rounds. Compared to prior lattice-based partially non-interactive assumptions (CRYPTO '24, S&P '25, CRYPTO '25), we achieve better communication complexity in addition to stronger security guarantees.