International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: SCALES: MPC with Small Clients and Larger Ephemeral Servers

Anasuya Acharya , Bar-Ilan University
Carmit Hazay , Bar-Ilan University
Vladimir Kolesnikov , Georgia Institute of Technology
Manoj Prabhakaran , Indian Institute of Technology Bombay
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Presentation: Slides
Conference: TCC 2022
Abstract: The recently proposed YOSO model is a groundbreaking approach to MPC, executable on a public blockchain, circumventing adaptive player corruption by hiding the corruption targets until they are worthless. Players are selected unpredictably from a large pool to perform MPC sub-tasks, in which each selected player sends a single message (and reveals their identity). While YOSO MPC has attractive asymptotic complexity, unfortunately, it is concretely prohibitively expensive due to the cost of its building blocks. We propose a modification to the YOSO model that preserves resilience to adaptive server corruption, but allows for much more efficient protocols. In SCALES (Small Clients And Larger Ephemeral Servers) only the servers facilitating the MPC computation are ephemeral (unpredictably selected and ``speak once''). Input providers (clients) publish problem instance and collect the output, but do not otherwise participate in computation. SCALES offers attractive features, and improves over YOSO in outsourcing MPC to a large pool of servers under adaptive corruption. We build SCALES from rerandomizable garbling schemes, which is a contribution of independent interest, with additional applications.
  title={SCALES: MPC with Small Clients and Larger Ephemeral Servers},
  author={Anasuya Acharya and Carmit Hazay and Vladimir Kolesnikov and Manoj Prabhakaran},