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Theses

Signatures pour l'anonymat fondées sur les couplages et applications

Abstract : Anonymity issues arise in several situations, in the Internet context and specifically for electronic transactions. It is then advisable to protect the users' identities to avoid the construction of commercial information databases or the constitution of consumers' profiles. Many cryptographic solutions have been proposed to strengthen the users' confidence in these systems. A new approach in the elaboration of secure and efficient anonymous mechanisms is based on bilinear maps (Weil and Tate's pairings on elliptic curves). In this thesis, we first present a literature review of different signatures used for anonymity in cryptography, specially group signatures, blind signatures and ring signatures. Following this presentation, we describe a new protocol for authentication and show how it can be turned into a ring signature. We then focus our study on fair blind signatures. These are blind signatures enabling an authority to revoke their anonymity and untraceability. We propose the first actual security model for these signatures and a new construction based on bilinear maps, we then prove its security in this model. Our final works concern multi-coupon and electronic cash systems. The use of pairings allows us to introduce new properties aimed to simplify their utilization. For each of these systems we describe a security model, then describe a scheme and prove its security in this model.
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https://tel.archives-ouvertes.fr/tel-00258773
Contributor : Hal System <>
Submitted on : Monday, February 25, 2008 - 11:42:05 AM
Last modification on : Tuesday, February 5, 2019 - 12:12:10 PM
Long-term archiving on: : Thursday, May 20, 2010 - 11:30:43 PM

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  • HAL Id : tel-00258773, version 1

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Emeline Hufschmitt. Signatures pour l'anonymat fondées sur les couplages et applications. Autre. Université de Caen, 2007. Français. ⟨tel-00258773⟩

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