Delegatable Keyed-Verification Anonymous Credentials

Omid Mirzamohammadi; Varesh Mishra; Jan Bobolz; Emad Heydari Beni; Aysajan Abidin; Dave Singelée; Bart Preneel

Paper 2026/2860

Delegatable Keyed-Verification Anonymous Credentials

Omid Mirzamohammadi

, COSIC, KU Leuven

Varesh Mishra

, COSIC, KU Leuven

Jan Bobolz

, Hasso Plattner Institute, University of Potsdam

Emad Heydari Beni

, COSIC, KU Leuven & Nokia Bell Labs

Aysajan Abidin

, COSIC, KU Leuven

Dave Singelée

, DistriNet-Campus Group T, KU Leuven,

Bart Preneel

, COSIC, KU Leuven

Abstract

Keyed-verification anonymous credentials (KVACs) are a variant of anonymous credentials (ACs) in which the issuer and the verifier are either the same entity or mutually trusted entities. Due to this design, KVACs can avoid some of the practical burdens of publicly verifiable ACs, such as requiring bilinear pairings, making them more practical in certain settings. Delegation of credentials is a powerful feature that enables applications where users, holding a credential, can delegate a restricted version of their credential to another user. This paper proposes the first delegatable keyed-verification anonymous credentials (DKVAC). We provide formal definitions of DKVAC, we design two pairing-free DKVAC constructions with delegation capability, we prove them secure, and we demonstrate their practicality with implementation benchmarks. Our two constructions present trade-offs between expressiveness and performance.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: Delegatable Anonymous Credentials Keyed-Verification Anonymous Credentials Zero-Knowledge Proofs
Contact author(s): omid mirzamohammadi @ esat kuleuven be
varesh mishra @ esat kuleuven be
jan bobolz @ hpi de
emad heydaribeni @ esat kuleuven be
aysajan abidin @ esat kuleuven be
dave singelee @ kuleuven be
bart preneel @ esat kuleuven be
History: 2026-11-13: approved; 2026-11-10: received; See all versions
Short URL: https://ia.cr/2026/2860
License: CC BY

BibTeX

@misc{cryptoeprint:2026/2860,
      author = {Omid Mirzamohammadi and Varesh Mishra and Jan Bobolz and Emad Heydari Beni and Aysajan Abidin and Dave Singelée and Bart Preneel},
      title = {Delegatable Keyed-Verification Anonymous Credentials},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/2860},
      year = {2026},
      url = {https://eprint.iacr.org/2026/2860}
}