In the past few months, a range of protocols have been published, allowing for a non interactive -- and hence extremely efficient -- signing protocol; providing new features, such as identifiable aborts (parties can be held accountable if they cause the protocol to fail), fairness in the honest majority setting (all parties receive output or nobody does) and other properties. In some cases, security is proven in the strong simulation based model.
We combine ideas from the aforementioned articles with the suggestion of Castagnos \textit{et al.} (PKC 2020) to use the class group based $\mathsf{CL}$ framework so as to drastically reduce bandwidth consumption.
Building upon this latter protocol we present a new, maliciously secure, full threshold ECDSA protocol that achieving additional features without sacrificing efficiency. Our most basic protocol boasts a non interactive signature algorithm and identifiable aborts. We also propose a more advanced variant that also achieves adaptive security (for the $n$-out-of-$n$ case) and proactive security. Our resulting constructions improve upon state of the art Paillier's based realizations achieving similar goals by up to a 10 factor in bandwidth consumption.
Category / Keywords: cryptographic protocols / Threshold Signature, ECDSA, Proactive, Online/Offline, Class Groups, Bandwidth Efficient, Adaptive Security Date: received 5 Mar 2021, last revised 6 Mar 2021 Contact author: guilhem castagnos at math u-bordeaux fr, catalano at dmi unict it, Fabien Laguillaumie at lirmm fr, federico savasta at unict it, ida tucker at imdea org Available format(s): PDF | BibTeX Citation Version: 20210307:022643 (All versions of this report) Short URL: ia.cr/2021/291