Paper 2022/661

Protego: Efficient, Revocable and Auditable Anonymous Credentials with Applications to Hyperledger Fabric

Aisling Connolly, DFINITY
Jerome Deschamps, LIMOS, University Clermont Auvergne, France
Pascal Lafourcade, LIMOS, University Clermont Auvergne, France
Octavio Perez Kempner, DIENS, École normale supérieure, CNRS, PSL University, Paris, France, be-ys Research, France

Recent works to improve privacy in permissioned blockchains like Hyperledger Fabric rely on Idemix, the only anonymous credential system that has been integrated to date. The current Idemix implementation in Hyperledger Fabric (v2.4) only supports a fixed set of attributes; it does not support revocation features, nor does it support anonymous endorsement of transactions (in Fabric, transactions need to be approved by a subset of peers before consensus). A prototype Idemix extension by Bogatov et al. (CANS, 2021) was proposed to include revocation, auditability, and to gain privacy for users. In this work, we explore how to gain efficiency, functionality, and further privacy, departing from recent works on anonymous credentials based on Structure-Preserving Signatures on Equivalence Classes. As a result, we extend previous works to build a new anonymous credential scheme called Protego. We also present a variant of it (Protego Duo) based on a different approach to hiding the identity of an issuer during showings. We also discuss how both can be integrated into Hyperledger Fabric and provide a prototype implementation. Finally, our results show that Protego and Protego Duo are at least twice as fast as state-of-the-art approaches based on Idemix.

Note: This is a preliminary version of a paper accepted at INDOCRYPT 2022 under the same name

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. INDOCRYPT 2022
anonymous credentials auditability Hyperledger Fabric mercurial signatures permissioned blockchains
Contact author(s)
aislingmconnolly @ gmail com
jerome deschamps @ etu uca fr
pascal lafourcade @ uca fr
octavio perez kempner @ ens fr
2022-10-20: last of 3 revisions
2022-05-27: received
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      author = {Aisling Connolly and Jerome Deschamps and Pascal Lafourcade and Octavio Perez Kempner},
      title = {Protego: Efficient, Revocable and Auditable Anonymous Credentials with Applications to Hyperledger Fabric},
      howpublished = {Cryptology ePrint Archive, Paper 2022/661},
      year = {2022},
      note = {\url{}},
      url = {}
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