IACR News item: 23 February 2023
Yanbo Chen
ePrint Report
A multi-signature scheme allows multiple signers to jointly sign a common message. Recently, two lattice-based two-round multi-signature schemes based on Dilithium-G were proposed: DOTT by Damgård, Orlandi, Takahashi, and Tibouchi (PKC'21) and MuSig-L by Boschini, Takahashi, and Tibouchi (CRYPTO'22).
In this work, we propose a lattice-based two-round multi-signature scheme called DualMS. Compared to DOTT, DualMS is likely to significantly reduce signature size, since it replaces an opening to a homomorphic trapdoor commitment with a Dilithium-G response in the signature. Compared to MuSig-L, concrete parameters show that DualMS has smaller public keys, signatures, and lower communication, while the first round cannot be preprocessed offline as in MuSig-L.
The main reason behind such improvements is a trapdoor-free "dual signing simulation" of our scheme. Signature simulation of DualMS is virtually identical the normal signing procedure and does not use lattice trapdoors like DOTT and MuSig-L.
In this work, we propose a lattice-based two-round multi-signature scheme called DualMS. Compared to DOTT, DualMS is likely to significantly reduce signature size, since it replaces an opening to a homomorphic trapdoor commitment with a Dilithium-G response in the signature. Compared to MuSig-L, concrete parameters show that DualMS has smaller public keys, signatures, and lower communication, while the first round cannot be preprocessed offline as in MuSig-L.
The main reason behind such improvements is a trapdoor-free "dual signing simulation" of our scheme. Signature simulation of DualMS is virtually identical the normal signing procedure and does not use lattice trapdoors like DOTT and MuSig-L.
Additional news items may be found on the IACR news page.