IACR News item: 30 June 2015
Georg Fuchsbauer, Christian Hanser, Daniel Slamanig
ePrint ReportWe present a construction of practically efficient round-optimal blind signatures in the standard model. It is conceptually simple and builds on the recent structure-preserving signatures on equivalence classes (SPS-EQ) from Asiacrypt\'14. While the traditional notion of blindness follows from standard assumptions, we prove blindness under adversarially chosen keys under an interactive variant of DDH. However, we neither require non-uniform assumptions nor complexity leveraging.
We then show how to extend our construction to partially blind signatures and to blind signatures on message vectors, which yield a construction of one-show anonymous credentials à la \"anonymous credentials light\" (CCS\'13) in the standard model.
Furthermore, we give the first SPS-EQ construction under non-interactive assumptions and show how SPS-EQ schemes imply conventional structure-preserving signatures, which allows us to apply optimality results for the latter to SPS-EQ.
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