Divisible e-cash made practical

Sébastien Canard 1 David Pointcheval 2, 3 Olivier Sanders 1, 2, 3 Jacques Traoré 1
3 CASCADE - Construction and Analysis of Systems for Confidentiality and Authenticity of Data and Entities
DI-ENS - Département d'informatique de l'École normale supérieure, Inria Paris-Rocquencourt, CNRS - Centre National de la Recherche Scientifique : UMR 8548
Abstract : Divisible e-cash systems allow users to withdraw a unique coin of value 2 n units from a bank, but then to spend it in several times to distinct merchants. In such a system, whereas users want anonymity of their transactions, the bank wants to prevent, or at least detect, double-spending, and trace defrauders. While this primitive was introduced two decades ago, quite a few (really) anonymous constructions have been proposed. In addition, all but one were just proven secure in the random oracle model, but still with either weak security models or quite complex settings and thus costly constructions. The unique proposal, secure in the standard model, appeared recently and is unpractical. As evidence, the authors left the construction of an efficient scheme secure in this model as an open problem. In this study, the authors answer it with the first efficient divisible e-cash system secure in the standard model. It is based on a new way of building the coins, with a unique and public global tree structure for all the coins. Actually, they propose two constructions which offer a tradeoff between efficiency and security. They both achieve constant time for withdrawing and spending amounts of 2ℓ units, while allowing the bank to quickly detect double-spendings by a simple comparison of the serial numbers of deposited coins to the ones of previously spent coins.
Type de document :
Article dans une revue
IET Information Security, Institution of Engineering and Technology, 2016, 〈10.1049/iet-ifs.2015.0485〉
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Contributeur : David Pointcheval <>
Soumis le : samedi 8 octobre 2016 - 12:35:59
Dernière modification le : jeudi 11 janvier 2018 - 06:22:10




Sébastien Canard, David Pointcheval, Olivier Sanders, Jacques Traoré. Divisible e-cash made practical. IET Information Security, Institution of Engineering and Technology, 2016, 〈10.1049/iet-ifs.2015.0485〉. 〈hal-01377998〉



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