A New Approach to Practical Active-Secure Two-Party Computation

TL;DR

This paper introduces a novel OT-based protocol for active-secure two-party computation that outperforms previous methods in efficiency, enabling practical evaluation of large circuits with significant speed improvements.

Contribution

The authors develop a new OT extension technique within the random oracle model, achieving practical active-secure two-party computation without relying on Yao's garbled circuits.

Findings

Over 20,000 gates per second for large circuits

AES encryption evaluated in under 3 seconds after repetition

Protocol surpasses all previous efficiency benchmarks

Abstract

We propose a new approach to practical two-party computation secure against an active adversary. All prior practical protocols were based on Yao's garbled circuits. We use an OT-based approach and get efficiency via OT extension in the random oracle model. To get a practical protocol we introduce a number of novel techniques for relating the outputs and inputs of OTs in a larger construction. We also report on an implementation of this approach, that shows that our protocol is more efficient than any previous one: For big enough circuits, we can evaluate more than 20000 Boolean gates per second. As an example, evaluating one oblivious AES encryption (~34000 gates) takes 64 seconds, but when repeating the task 27 times it only takes less than 3 seconds per instance.