Secure multi-party computation: promises, protocols, and practicalities

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Presented at ParisCryptoDay 2017 by

David Evans

Secure multi-party computation (MPC) provides a way for two (or more) parties to compute a function that depends on inputs from both parties, while keeping their inputs private. A general solution to this problem have been known since Yao’s pioneering work on garbled circuits in the 1980s, but only recently has it become conceivable to use this approach in real systems. Over the past decade, the costs of executing MPC protocols have dropped by about 7 orders of magnitude, but real-world deployments remain rare, and mostly unsatisfying. In this talk, I’ll provide a brief introduction to MPC and summarize some of the work our group has done to make secure computation scalable, efficient, and accessible. I’ll describe some attempts to build interesting practical systems with MPC including an ongoing effort to develop a decentralized certificate authority that can produce signed certificates without ever exposing the private signing key. Finally, I’ll discuss the remaining impediments that are holding back MPC from being widely used in practice.