Crypto/Applied Crypto Seminar

Thursday, April 8, 2021 – 4:30pm to 5:30pm


Virtual Presentation – ET Remote Access – Zoom



Malicious Security Comes Free in Honest-Majority Multiparty Computation

Since the notion of Multiparty Computation (MPC) was proposed three decades ago, a lot of research and effort has been done to improve the efficiency of MPC protocols. However, the inefficiency of the current state of the art is still the major barrier which prevents MPC from being used more broadly.

In this talk, we focus on unconditional (or information-theoretical) MPC. A key feature of unconditional MPC is that we do not need any expensive cryptographic primitive (such as public-key encryption or oblivious transfer) and the protocol is secure unconditionally. Comparing with the protocols in the computational setting (i.e., with security relying on cryptographic assumptions), one major benefit is that protocols usually do not require complicated and time-consuming local computations. In particular, local computations are often just a series of linear operations. As a result, the most efficient MPC protocols are in the unconditional MPC paradigm. And the main criterion for the efficiency of unconditional MPC protocols is the amount of communication between every pair of parties.

We will start with a short review of the notion of MPC. Then we will introduce the Damgard and Nielsen protocol (DN protocol), the best-known communication-efficient unconditional MPC protocol in the semi-honest setting. Next, we will show how previous works achieve malicious security using the DN protocol. Finally, we will introduce our techniques, which allows us to achieve malicious security with the same concrete efficiency as the semi-honest DN protocol.

Zoom Participation. See announcement.

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