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Cryptography for Pragmatic Distributed Trust and the Role of Blockchain

Quentin Santos 1, 2
1 CASCADE - Construction and Analysis of Systems for Confidentiality and Authenticity of Data and Entities
DI-ENS - Département d'informatique de l'École normale supérieure, CNRS - Centre National de la Recherche Scientifique : UMR 8548, Inria de Paris
Abstract : In this thesis, we explore cryptographic methods to solve concrete problems. First, we study the technology “Blockchain”, recently introduced by the cryptocurrency “Bitcoin”. In particular, we ponder whether this technology can help in solving new problems or in providing more efficient solutions. We clarify which properties are brought by cryptography, and which are particular to Blockchain. We consider the use case of organ donation and the conditions that donors and recipients must meet. We then offer a solution that makes a reasonable trade-off between speed and security. This takes the form of a new cryptographic primitive tailored to the specificities of the problem. Furthermore, we consider the use case of online and electronic voting and the possibilities offered by the more advanced voting systems. We then design a cryptographic protocol that guarantees confidentiality and integrity to implement Majority Judgment. Along with the theoretical construction, we implement a proof of concept and provide benchmarks that show reasonable running times. In the end, it appears that Blockchain does not adapt well to these use cases, but that currency cryptographic techniques can do more that usually assumed by non-specialists.
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Submitted on : Thursday, December 27, 2018 - 2:49:47 PM
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Cryptography for Pragmatic Dis...
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  • HAL Id : tel-01966109, version 1



Quentin Santos. Cryptography for Pragmatic Distributed Trust and the Role of Blockchain. Cryptography and Security [cs.CR]. PSL Research University; École Normale Supérieure, 2018. English. ⟨tel-01966109⟩



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