Lattice-based Threshold Ring Signature with Message Block Sharing
Jiangshan Chen, Yupu Hu, Wen Gao, Hongmei Liang · KSII Transactions on Internet and Information Systems · 2019
Threshold ring signature scheme enables any t entities from N ring members to spontaneously generate a publicly verifiable t-out-of-N signature anonymously.The verifier is convinced that the signature is indeed generated by at least t users from the claimed group, but he cannot tell them apart.Threshold ring signatures are significant for ad-hoc groups such as mobile ad-hoc networks.Based on the lattice-based ring signature proposed by Melchor et al. at AFRICRYPT'13, this work presents a lattice-based threshold ring signature scheme, employing the technique of message block sharing proposed by Choi and Kim.Besides, in order to avoid the system parameter setup problems, we proposed a message processing technique called "pad-then-permute", to pre-process the message before blocking the message, thus making the threshold ring signature scheme more flexible.Our threshold ring signature scheme has several advantages: inherits the quantum immunity from the lattice structure; has considerably short signature and almost no signature size increase with the threshold value; provable to be correct, efficient, indistinguishable source hiding, and unforgeable.