An optimistic fair exchange protocol with active intermediaries

Draper-Gil, Gerard; Zhou, Jianying; Ferrer-Gomila, Josep Lluís; Hinarejos, M. Francisca

doi:10.1007/s10207-013-0194-9

Cited by 6 publications

(5 citation statements)

References 25 publications

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“…Some authors [19,[21][22][23][24][25][26][27][28][29][30][31] used definitions that fit the definition we have called hard-timeliness. While other authors [8,9,13,15,[32][33][34][35][36][37][38][39][40][41][42][43][44][45] used definitions that fit the definition we have called soft-timeliness. Some introduced nuance: predetermined time [34,37], agreed time [35,36], bounded time [39], or that the protocol defines a deadline [45].…”

Section: Timelinessmentioning

confidence: 99%

A Hard-Timeliness Blockchain-Based Contract Signing Protocol

Ferrer-Gomila,

Hinarejos

2023

Computers

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In this article, we present the first proposal for contract signing based on blockchain that meets the requirements of fairness, hard-timeliness, and bc-optimism. The proposal, thanks to the use of blockchain, does not require the use of trusted third parties (TTPs), thus avoiding a point of failure and the problem of signatories having to agree on a TTP that is trusted by both. The presented protocol is fair because it is designed such that no honest signatory can be placed at a disadvantage. It meets the hard-timeliness requirement because both signatories can end the execution of the protocol at any time they wish. Finally, the proposal is bc-optimistic because blockchain functions are only executed in case of exception (and not in each execution of the protocol), with consequent savings when working with public blockchains. No previous proposal simultaneously met these three requirements. In addition to the above, this article clarifies the concept of timeliness, which previously has been defined in a confusing way (starting with the authors who used the term for the first time). We conducted a security review that allowed us to verify that our proposal meets the desired requirements. Furthermore, we provide the specifications of a smart contract designed for the Ethereum blockchain family and verified the economic feasibility of the proposal, ensuring it can be aligned with the financial requirements of different scenarios.

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Section: Timelinessmentioning

confidence: 99%

A Hard-Timeliness Blockchain-Based Contract Signing Protocol

Ferrer-Gomila,

Hinarejos

2023

Computers

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“…(11) = ( , , ): the evidence of signatured cryptograph from originator to ; (12) = ( , , ): signatured cryptograph from originator to receives evidence;…”

Section: 1mentioning

confidence: 99%

“…In the recent years, some formal methods have been developed which are suitable for the analysis of nonrepudiation protocols; see, for example, [9][10][11]. However, fairness analysis for multi-party nonrepudiation protocols seems to be more complex, and only nonformal analysis for fairness, 2 Discrete Dynamics in Nature and Society and so on, has been done by utilizing various typical kinds of nonrepudiation protocols in [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Fairness Analysis for Multiparty Nonrepudiation Protocols Based on Improved Strand Space

Wang

Chen

et al. 2014

Discrete Dynamics in Nature and Society

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Aimed at the problem of the fairness analysis for multiparty nonrepudiation protocols, a new formal analysis method based on improved strand space is presented. Based on the strand space theory, signature operation is added; the set of terms, the subterm relation and the set of penetrator traces are redefined and the assumption of free encryption is extended in the new method. The formal definition of fairness in multi-party non-repudiation protocols is given and the guideline to verify it based on improved strand space is presented. Finally, the fairness of multi-party non-repudiation protocols is verified with an example of Kremer-Markowitch protocol, which indicates that the new method is suitable for analyzing the fairness of multiparty nonrepudiation protocols. Hindawi Publishing Corporation

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“…Fair exchange protocols [1][2][3][4][5] are mainly used to ensure the security and fairness of online transactions and they are very important. A good fair exchange protocol can make both parties exchange information in a fair way, i.e., after the completion of exchange, either each party gets the other's information or neither party does.…”

Section: Introductionmentioning

confidence: 99%

“…Early fair exchange protocols are usually gradual exchange protocols [1][2], and they always take both parties many steps to finish the exchange and are very inefficient. Another class of fair exchange protocols [3][4][5] use a trusted third party (TTP) to achieve fairness, but since these protocols require the TTP must be fully trusted, it is sometimes hard for us to find such a TTP. In 2004, Chen et al [6] introduced the notion of concurrent signature.…”

Section: Introductionmentioning

confidence: 99%

Improved Fair Exchange Protocol Based on Signcryption-Based Concurrent Signature

Ye¹,

Guo²,

Yang³

et al. 2013

JSW

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Through analysis, we point out Luo et al.’s and Sun et al.’s signcryption-based concurrent signature schemes have the same defect in ambiguity and therefore the fair exchange protocols based on their schemes are not fair. Thus based on the notions of signcryption and concurrent signature, a new signcryption-based concurrent signature scheme from bilinear pairing is presented, and based on this scheme, a new fair exchange protocol is proposed. Since we adopt a new method to construct the new signcryption-based concurrent signature scheme, the new scheme redresses the flaw of Luo et al.’s and Sun et al.’s schemes, and the fair exchange protocol based on the new scheme is also fair. Besides, due to the new scheme’s independence of the ring signature and simplification of encryption operations, the new scheme has the advantage of short signatures and low computation cost. We improve Luo et al.’s definition of the security model of a signcryption-based concurrent signature scheme and prove the proposed scheme and protocol are secure under the computational Diffie-Hellman assumption in the random oracle model.

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An optimistic fair exchange protocol with active intermediaries

Cited by 6 publications

References 25 publications

A Hard-Timeliness Blockchain-Based Contract Signing Protocol

A Hard-Timeliness Blockchain-Based Contract Signing Protocol

Fairness Analysis for Multiparty Nonrepudiation Protocols Based on Improved Strand Space

Improved Fair Exchange Protocol Based on Signcryption-Based Concurrent Signature

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