Optimistic fair exchange of ring signatures

Lie Qu*, Guilin Wang, Yi Mu

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

5 Citations (Scopus)


An optimistic fair exchange (OFE) protocol is an effective tool helping two parties exchange their digital items in an equitable way with assistance of a trusted third party, called arbitrator, who is only required if needed. In previous studies, fair exchange is usually carried out between individual parties. When fair exchange is carried out between two members from distinct groups, anonymity of the signer in a group could be necessary for achieving better privacy. In this paper, we consider optimistic fair exchange of ring signatures (OFERS), i.e. two members from two different groups can exchange their ring signatures in a fair way with ambiguous signers. Each user in these groups has its own public-private key pair and is able to sign a message on behalf of its own group anonymously. We first define the security model of OFERS in the multi-user setting under adaptive chosen message, chosen-key and chosen public-key attacks. Then, based on verifiably encrypted ring signatures (VERS) we construct a concrete scheme by combining the technologies of ring signatures, public-key encryption and proof of knowledge. Finally, we show that our OFERS solution is provably secure in our security model, and preserving signer-ambiguity of ring signatures. To the best of our knowledge, this is the first (formal) work on this topic.

Original languageEnglish
Title of host publicationSecurity and privacy in communication networks
Subtitle of host publication7th international ICST conference, SecureComm 2011: revised selected papers
EditorsMuttukrishnan Rajarajan, Fred Piper, Haining Wang, George Kesidis
Place of PublicationBerlin
PublisherSpringer, Springer Nature
Number of pages16
ISBN (Electronic)9783642319099
ISBN (Print)9783642319082
Publication statusPublished - 2012
Externally publishedYes
Event7th International ICST Conference on Security and Privacy in Communication Networks, SecureComm 2011 - London, United Kingdom
Duration: 7 Sep 20119 Sep 2011

Publication series

NameLecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering
Volume96 LNICST
ISSN (Print)18678211


Other7th International ICST Conference on Security and Privacy in Communication Networks, SecureComm 2011
Country/TerritoryUnited Kingdom


  • optimistic fair exchange
  • privacy
  • ring signatures
  • verifiably encrypted signatures (VES)


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