Universally Composable Interactive and Ordered Multi-signatures
Paper i proceeding, 2025

Multi-signatures allow a given set of parties to cooperate in order to create a digital signature whose size is independent of the number of signers. At the same time, no other set of parties can cre ate such a signature. While non-interactive multi-signatures are known (e.g. BLS from pairings), many popular multi-signature schemes such as MuSig2 (which are constructed from pairing-free discrete logarithm-style assumptions) require interaction. Such interactive multi-signatures have recently found practical applications e.g. in the cryptocurrency space. Motivated by classical and emerging use cases of such interactive multi-signatures, we introduce the first systematic treatment of inter active multi-signatures in the universal composability (UC) framework. Along the way, we revisit existing game-based security notions and prove that constructions secure in the game-based setting can easily be made UC secure and vice versa. In addition, we consider interactive multi-signatures where the sign ers must interact in a fixed pattern (so-called ordered multi-signatures). Here, we provide the first construction of ordered multi-signatures based on the one-more discrete logarithm assumption, whereas the only other previously known construction required pairings. Our scheme achieves a stronger notion of unforgeability, guaranteeing that the adversary can not obtain a signature altering the relative order of honest signers. We also present the first formalization of ordered multi-signatures in the UC framework and again show that our stronger game-based definitions are equivalent to UC security.

Författare

Carsten Baum

Danmarks Tekniske Universitet (DTU)

Bernardo David

IT-Universitetet i Kobenhavn

Elena Pagnin

Chalmers, Data- och informationsteknik, Informationssäkerhet

Akira Takahashi

JPMorgan Chase & Co.

Lecture Notes in Computer Science

0302-9743 (ISSN) 1611-3349 (eISSN)

Vol. 15675 LNCS 3-31
9783031918223 (ISBN)

28th IACR International Conference on Practice and Theory of Public Key Cryptography, PKC 2025
Røros, Norway,

Gradvis kryptografiska verifierings mekanismer

Vetenskapsrådet (VR) (2022-04684), 2023-01-01 -- 2026-12-31.

Ämneskategorier (SSIF 2025)

Datavetenskap (datalogi)

DOI

10.1007/978-3-031-91823-0_1

Mer information

Senast uppdaterat

2025-06-04