International Association for Cryptologic Research

International Association
for Cryptologic Research


How to Obfuscate MPC Inputs

Ian McQuoid , Oregon State University
Mike Rosulek , Oregon State University
Jiayu Xu , Oregon State University
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Presentation: Slides
Conference: TCC 2022
Abstract: We introduce the idea of input obfuscation for secure two-party computation (io2PC). Sup- pose Alice holds a private value x and wants to allow clients to learn f (x, yi), for their choice of yi, via a secure computation protocol. The goal of io2PC is for Alice to encode x so that an adversary who compromises her storage gets only oracle access to the function f (x, ·). At the same time, there must be a 2PC protocol for computing f (x, y) that takes only this encoding (and not the plaintext x) as input. We show how to achieve io2PC for functions that have virtual black-box (VBB) obfuscation in either the random oracle model or generic group model. For functions that can be VBB- obfuscated in the random oracle model, we provide an io2PC protocol by replacing the random oracle with an oblivious PRF. For functions that can be VBB-obfuscated in the generic group model, we show how Alice can instantiate a “personalized” generic group. A personalized generic group is one where only Alice can perform the algebraic operations of the group, but where she can let others perform operations in that group via an oblivious interactive protocol.
  title={How to Obfuscate MPC Inputs},
  author={Ian McQuoid and Mike Rosulek and Jiayu Xu},