Tianren Liu: Information-Theoretic 2-Round MPC without Round Collapsing

Friday, October 23, 2020 - 1:00pm to 2:30pm
Please email dlehto@mit.edu for Zoom Link
Tianren Liu
We present simpler and improved constructions of 2-round protocols for secure multi-party computation (MPC) in the semi-honest setting.  Our main results are new information-theoretically secure protocols for arithmetic NC1 in two settings:
(i) the plain model tolerating up to $t < n/2$ corruptions; and
(ii) in the OLE-correlation model tolerating any number of corruptions.

Our protocols achieve adaptive security and require only black-box access to the underlying field. Moreover, both results extend to polynomial-size circuits with computational and adaptive security, while relying on black-box access to a pseudorandom generator. In the OLE correlation model, the extended protocols for circuits tolerate up to $n-1$ corruptions.  

Along the way, we introduce a conceptually novel framework for 2-round MPC that does not rely on the round collapsing framework underlying all of the recent advances in 2-round MPC (Benhamouda Lin EC18, Garg Srinivasan EC18, Applebaum Brakerski Tsabary TCC18 etc).

Joint work with Rachel Lin and Hoeteck Wee.
The paper can be downloaded from liutianren.com.