Paper 2018/037

Weakly Secure Equivalence-Class Signatures from Standard Assumptions

Georg Fuchsbauer and Romain Gay


Structure-preserving signatures on equivalence classes, or equivalence-class signatures for short (EQS), are signature schemes defined over bilinear groups whose messages are vectors of group elements. Signatures are perfectly randomizable and given a signature on a vector, anyone can derive a signature on any multiple of the vector; EQS thus sign projective equivalence classes. Applications of EQS include the first constant-size anonymous attribute-based credentials, efficient round-optimal blind signatures without random oracles and efficient access-control encryption. To date, the only existing instantiation of EQS is proven secure in the generic-group model. In this work we show that by relaxing the definition of unforgeability, which makes it efficiently verifiable, we can construct EQS from standard assumptions, namely the Matrix-Diffie-Hellman assumptions. We then show that our unforgeability notion is sufficient for most applications.

Available format(s)
Publication info
Published by the IACR in PKC 2018
Structure-preserving signaturessecurity proofstandard assumptions.
Contact author(s)
rgay @ di ens fr
Georg Fuchsbauer @ ens fr
2018-01-08: received
Short URL
Creative Commons Attribution


      author = {Georg Fuchsbauer and Romain Gay},
      title = {Weakly Secure Equivalence-Class Signatures from Standard Assumptions},
      howpublished = {Cryptology ePrint Archive, Paper 2018/037},
      year = {2018},
      note = {\url{}},
      url = {}
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