Paper 2022/011

Security Analysis of Coconut, an Attribute-Based Credential Scheme with Threshold Issuance

Alfredo Rial and Ania M. Piotrowska

Abstract

Coconut [NDSS 2019] is an attribute-based credential scheme with threshold issuance. We analyze its security properties. To this end, we define an ideal functionality for attribute-based access control with threshold issuance. We describe a construction that realizes our functionality. Our construction follows Coconut with a few changes. In particular, it modifies the protocols for blind issuance of credentials and for credential show so that user privacy holds against computationally unbounded adversaries. The modified protocols are slightly more efficient than those of Coconut. Our construction also extends the public key, which seems necessary to prove unforgeability.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint. MINOR revision.
Keywords
Public-key cryptographydigital signatureszero knowledge
Contact author(s)
alfredo @ nymtech net
History
2022-04-22: revised
2022-01-07: received
See all versions
Short URL
https://ia.cr/2022/011
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2022/011,
      author = {Alfredo Rial and Ania M.  Piotrowska},
      title = {Security Analysis of Coconut, an Attribute-Based Credential Scheme with Threshold Issuance},
      howpublished = {Cryptology ePrint Archive, Paper 2022/011},
      year = {2022},
      note = {\url{https://eprint.iacr.org/2022/011}},
      url = {https://eprint.iacr.org/2022/011}
}
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