International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: How to Win the Clone Wars: \\ Efficient Periodic n-Times Anonymous Authentication

Jan Camenisch
Susan Hohenberger
Markulf Kohlweiss
Anna Lysyanskaya
Mira Meyerovich
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Abstract: We create a credential system that lets a user anonymously authenticate at most $n$ times in a single time period. A user withdraws a dispenser of $n$ e-tokens. She shows an e-token to a verifier to authenticate herself; each e-token can be used only once, however, the dispenser automatically refreshes every time period. The only prior solution to this problem, due to Damg{\aa}rd et al.~[DDP05], uses protocols that are a factor of $k$ slower for the user and verifier, where $k$ is the security parameter. Damg{\aa}rd et al. also only support one authentication per time period, while we support $n$. Because our construction is based on e-cash, we can use existing techniques to identify a cheating user, trace all of her e-tokens, and revoke her dispensers. We also offer a new anonymity service: glitch protection for basically honest users who (occasionally) reuse e-tokens. The verifier can always recognize a reused e-token; however, we preserve the anonymity of users who do not reuse e-tokens too often.
  title={How to Win the Clone Wars: \\ Efficient Periodic n-Times Anonymous Authentication},
  booktitle={IACR Eprint archive},
  keywords={cryptographic protocols / electronic commerce and payment, e-cash},
  note={Full version of an extended abstract published in Proceedings of ACM CCS 2006, ACM Press. 13615 received 30 Nov 2006, last revised 11 Apr 2007},
  author={Jan Camenisch and Susan Hohenberger and Markulf Kohlweiss and Anna Lysyanskaya and Mira Meyerovich},