A digital signature scheme secure against adaptive chosen-message attacks
SIAM Journal on Computing - Special issue on cryptography
Optimistic protocols for fair exchange
Proceedings of the 4th ACM conference on Computer and communications security
Simple and fast optimistic protocols for fair electronic exchange
Proceedings of the twenty-second annual symposium on Principles of distributed computing
Constructing fair-exchange protocols for E-commerce via distributed computation of RSA signatures
Proceedings of the twenty-second annual symposium on Principles of distributed computing
Breaking and repairing optimistic fair exchange from PODC 2003
Proceedings of the 3rd ACM workshop on Digital rights management
Universally Composable Protocols with Relaxed Set-Up Assumptions
FOCS '04 Proceedings of the 45th Annual IEEE Symposium on Foundations of Computer Science
An abuse-free fair contract signing protocol based on the RSA signature
WWW '05 Proceedings of the 14th international conference on World Wide Web
Multi-party stand-alone and setup-free verifiably committed signatures
PKC'07 Proceedings of the 10th international conference on Practice and theory in public-key cryptography
Efficient ring signatures without random oracles
PKC'07 Proceedings of the 10th international conference on Practice and theory in public-key cryptography
Aggregate and verifiably encrypted signatures from bilinear maps
EUROCRYPT'03 Proceedings of the 22nd international conference on Theory and applications of cryptographic techniques
Stand-Alone and setup-free verifiably committed signatures
CT-RSA'06 Proceedings of the 2006 The Cryptographers' Track at the RSA conference on Topics in Cryptology
Evaluating 2-DNF formulas on ciphertexts
TCC'05 Proceedings of the Second international conference on Theory of Cryptography
Efficient identity-based encryption without random oracles
EUROCRYPT'05 Proceedings of the 24th annual international conference on Theory and Applications of Cryptographic Techniques
Sequential aggregate signatures and multisignatures without random oracles
EUROCRYPT'06 Proceedings of the 24th annual international conference on The Theory and Applications of Cryptographic Techniques
Ring signatures: stronger definitions, and constructions without random oracles
TCC'06 Proceedings of the Third conference on Theory of Cryptography
Optimistic fair exchange of digital signatures
IEEE Journal on Selected Areas in Communications
Ring signatures of sub-linear size without random oracles
ICALP'07 Proceedings of the 34th international conference on Automata, Languages and Programming
Ambiguous Optimistic Fair Exchange
ASIACRYPT '08 Proceedings of the 14th International Conference on the Theory and Application of Cryptology and Information Security: Advances in Cryptology
Fair exchange protocol of Schnorr signatures with semi-trusted adjudicator
Computers and Electrical Engineering
A new construction of designated confirmer signature and its application to optimistic fair exchange
Pairing'10 Proceedings of the 4th international conference on Pairing-based cryptography
One-time trapdoor one-way functions
ISC'10 Proceedings of the 13th international conference on Information security
Group-oriented fair exchange of signatures
Information Sciences: an International Journal
Fair and abuse-free contract signing protocol from Boneh-Boyen signature
EuroPKI'10 Proceedings of the 7th European conference on Public key infrastructures, services and applications
Concurrent signatures with fully negotiable binding control
ProvSec'11 Proceedings of the 5th international conference on Provable security
Further observations on optimistic fair exchange protocols in the multi-user setting
PKC'10 Proceedings of the 13th international conference on Practice and Theory in Public Key Cryptography
PKC'12 Proceedings of the 15th international conference on Practice and Theory in Public Key Cryptography
Perfect ambiguous optimistic fair exchange
ICICS'12 Proceedings of the 14th international conference on Information and Communications Security
Information Sciences: an International Journal
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Optimistic fair exchange is a kind of protocols to solve the problem of fair exchange between two parties. Almost all the previous work on this topic are provably secure only in the random oracle model. In PKC 2007, Dodis et al. considered optimistic fair exchange in a multiuser setting, and showed that the security of an optimistic fair exchange in a single-user setting may no longer be secure in a multi-user setting. Besides, they also proposed one and reviewed several previous construction paradigms and showed that they are secure in the multi-user setting. However, their proofs are either in the random oracle model, or involving a complex and very inefficient NP-reduction. Furthermore, they only considered schemes in the certified-key model in which each user has to show his knowledge of the private key corresponding to his public key. In this paper, we make the following contributions. First, we consider a relaxed model called chosen-key model in the context of optimistic fair exchange, in which the adversary can arbitrarily choose public keys without showing the knowledge of the private keys. We separate the security of optimistic fair exchange in the chosen-key model from the certified-key model by giving a concrete counterexample. Second, we strengthen the previous static security model in the multi-user setting to a more practical one which allows an adversary to choose a key adaptively. Third, we propose an efficient and generic optimistic fair exchange scheme in the multi-user setting and chosen-key model. The security of our construction is proven without random oracles. We also propose some efficient instantiations.