Paper 2023/1896

Selective Delegation of Attributes in Mercurial Signature Credentials

Colin Putman, Royal Holloway University of London
Keith M. Martin, Royal Holloway University of London
Abstract

Anonymous credential schemes enable service providers to verify information that a credential holder willingly discloses, without needing any further personal data to corroborate that information, and without allowing the user to be tracked from one interaction to the next. Mercurial signatures are a novel class of anonymous credentials which show good promise as a simple and efficient construction without heavy reliance on zero-knowledge proofs. However, they still require significant development in order to achieve the functionality that most existing anonymous credential schemes provide. Encoding multiple attributes of the credential holder in such a way that they can be disclosed selectively with each use of the credential is often seen as a vital feature of anonymous credentials, and is one that mercurial signatures have not yet implemented. In this paper, we show a simple way to encode attributes in a mercurial signature credential and to regulate which attributes a credential holder can issue when delegating their credential to another user. We also extend the security model associated with mercurial signatures to account for the inclusion of attributes, and prove the security of our extension with respect to the original mercurial signature construction.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. Major revision. IMA Cryptography and Coding 2023
DOI
10.1007/978-3-031-47818-5_10
Keywords
PrivacyAnonymous credentialsDelegatable credentialsMercurial signaturesSelective disclosure
Contact author(s)
Colin Putman 2017 @ live rhul ac uk
Keith Martin @ rhul ac uk
History
2023-12-11: approved
2023-12-10: received
See all versions
Short URL
https://ia.cr/2023/1896
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2023/1896,
      author = {Colin Putman and Keith M. Martin},
      title = {Selective Delegation of Attributes in Mercurial Signature Credentials},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1896},
      year = {2023},
      doi = {10.1007/978-3-031-47818-5_10},
      url = {https://eprint.iacr.org/2023/1896}
}
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