Paper 2007/182
Optimistic Fair Exchange in a Multi-user Setting
Yevgeniy Dodis, Pil Joong Lee, and Dae Hyun Yum
Abstract
This paper addresses the security of optimistic fair exchange in a multi-user setting. While the security of public key encryption and public key signature schemes in a single-user setting guarantees the security in a multi-user setting, we show that the situation is different in the optimistic fair exchange. First, we show how to break, in the multi-user setting, an optimistic fair exchange scheme provably secure in the single-user setting. This example separates the security of optimistic fair exchange between the single-user setting and the multi-user setting. We then define the formal security model of optimistic fair exchange in the multi-user setting, which is the first complete security model of optimistic fair exchange in the multi-user setting. We prove the existence of a generic construction meeting our multi-user security based on one-way functions in the random oracle model and trapdoor one-way permutations in the standard model. Finally, we revisit two well-known methodologies of optimistic fair exchange, which are based on the verifiably encrypted signature and the sequential two-party multisignature, respectively. Our result shows that these paradigms remain valid in the multi-user setting.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Published elsewhere. A preliminary version appeared in PKC 2007.
- Keywords
- fair exchange
- Contact author(s)
- dhyum @ postech ac kr
- History
- 2007-05-20: received
- Short URL
- https://ia.cr/2007/182
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2007/182,
author = {Yevgeniy Dodis and Pil Joong Lee and Dae Hyun Yum},
title = {Optimistic Fair Exchange in a Multi-user Setting},
howpublished = {Cryptology ePrint Archive, Paper 2007/182},
year = {2007},
note = {\url{https://eprint.iacr.org/2007/182}},
url = {https://eprint.iacr.org/2007/182}
}
