Identity-based Blind Multisignature from Lattices

Abstract

Blind multisignature (BMS), first introduced by Horster et al, constitutes a crucial primitive that allows a user to generate a signature of a message from multiple signers, while the signers cannot obtain any information about the message. With these useful properties, blind multisignature is suitable for electronic payments and electronic voting. However, most of the current BMS schemes may be attacked by quantum computers in the future because they are based on traditional number theories, such as discrete logarithm assumption and large integer factor assumption. In this work, we first formalize the notion and the sound security models of the identity-based blind multisignature scheme (IDBMS). Then we present an instantiation based on lattices, along with rigorous proofs of the blindness and unforgeability under the lattice hard assumption (short integer solution, SIS), which is considered to remain secure under quantum computer attacks. To the best of our knowledge, it is the first identity-based quantum-resistant scheme that has the advantages of blind signature and multisignature.