ABY – A Framework for Efficient Mixed-Protocol Secure Two-Party Computation
Download: Paper (PDF)
Date: 7 Feb 2015
Document Type: Briefing Papers
Additional Documents: Slides
Associated Event: NDSS Symposium 2015
Secure computation enables multiple mutually distrusting parties to jointly evaluate functions on their private inputs without revealing anything but the result. Generic secure computation protocols in the semi-honest model have been studied extensively and several best practices have evolved. In this work, we design and implement a mixed-protocol framework, called ABY, that efficiently combines secure computation schemes based on Arithmetic sharing, Boolean sharing, and Yao’s garbled circuits and that makes available best practice solutions in secure two-party computation. Our framework allows to pre-compute almost all cryptographic operations and provides novel highly efficient conversions between secure computation schemes based on pre-computed oblivious transfer extensions. ABY supports several standard operations and we perform benchmarks on a local network and in a public intercontinental cloud. From our benchmarks we deduce new insights on the efficient design of secure computation protocols, most prominently that oblivious transfer-based multiplications are much more efficient than using homomorphic encryption. We use our framework to construct mixed-protocols for three example applications, private set intersection, biometric matching, and modular exponentiation, and show that they are much more efficient than using a single protocol.