Paper 2025/513
Server-Aided Anonymous Credentials
, University of Washington, Brown University, Brown University, University of WashingtonAbstract
This paper formalizes the notion of server-aided anonymous credentials (SAACs), a new model for anonymous credentials (ACs) where, in the process of showing a credential, the holder is helped by additional auxiliary information generated in an earlier (anonymous) interaction with the issuer. This model enables lightweight instantiations of 'publicly verifiable and multi-use' ACs from pairing-free elliptic curves, which is important for compliance with existing national standards. A recent candidate for the EU Digital Identity Wallet, BBS#, roughly adheres to the SAAC model we have developed; however, it lacks formal security definitions and proofs.
In this paper, we provide rigorous definitions of security for SAACs, and show how to realize SAACs from the weaker notion of keyed-verification ACs (KVACs) and special types of oblivious issuance protocols for zero-knowledge proofs. We instantiate this paradigm to obtain two constructions: one achieves statistical anonymity with unforgeability under the Gap
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint.
- Keywords
- Anonymous CredentialsBBS SignaturesPairing-free Groups
- Contact author(s)
-
rchairat @ cs washington edu
franklin_harding @ brown edu
anna_lysyanskaya @ brown edu
tessaro @ cs washington edu - History
- 2025-03-21: approved
- 2025-03-19: received
- See all versions
- Short URL
- https://ia.cr/2025/513
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2025/513,
author = {Rutchathon Chairattana-Apirom and Franklin Harding and Anna Lysyanskaya and Stefano Tessaro},
title = {Server-Aided Anonymous Credentials},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/513},
year = {2025},
url = {https://eprint.iacr.org/2025/513}
}
