THE SMART CONTRACT MODEL OF ASYNCHRONOUS, ROBUST MPC

Gandlur, Shreyas

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https://hdl.handle.net/2142/125095 Copy

Description

Title

THE SMART CONTRACT MODEL OF ASYNCHRONOUS, ROBUST MPC

Author(s)

Gandlur, Shreyas

Issue Date

2020-05-01

Keyword(s)

multiparty computation; cryptographic protocols; universal composability; protocol security

Abstract

Over the past few years, massive cyberattacks have dominated the public imagination. Most Americans have been directly affected by data breaches and an overwhelming majority believe that they are no longer in control of their data. At the same time, there are important applications in which the aggregation of private data is unavoidable. Not surprisingly, there has been considerable interest in developing protocols for secure multi-party computation (MPC), i.e., N parties providing private inputs to jointly compute some function f. Recent developments in MPC have led to leaps in efficiency and MPCisquickly becoming a practical approach for privacy-centric distributed applications. As MPC applications become deployed, guaranteeing the security of these protocols, even when interacting with other applications, is essential. The standard approach to showing security of MPC protocols under arbitrary composition is through the universal composability (UC) framework. There has been much prior work on this topic; however, most previous work either makes synchronicity assumptions or does not guarantee output delivery in the presence of even one fault. For practical MPC applications, though, dealing with asynchronicity and robustness is essential. In this thesis, we describe two new keywords, eventually and leak, that aid in defining protocols in the asynchronous world and define wrappers that implement these within the UCframework. We then use this novel wrapper to give a UC-realization of a reliable broadcast primitive, by means of Bracha’s classic protocol. Finally, we define and prove a realization of what we call the smart contract model of MPC, which serves as a UC-idealization of asynchronous, robust MPC.

Type of Resource

text

Language

eng

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