Paper 2019/1098

Full-Threshold Actively-Secure Multiparty Arithmetic Circuit Garbling

Eleftheria Makri and Tim Wood

Abstract

We continue the study of Ben-Efraim (Asiacrypt 2018) on multiparty garbled circuits that contain both Boolean and arithmetic gates. Concretely, we extend the work of Ben-Efraim from the semi-honest, honest majority security model to the full-threshold actively secure equivalent. We further improve Ben-Efraim's selector gate. A selector gate is a gate that given two arithmetic inputs and one binary input, outputs one of the arithmetic inputs, based on the value of the selection bit input. Our new construction for the selector gate reduces the communication cost to almost half of that of Ben-Efraim's gate. This result applies both to the semi-honest and to the active security model.