Paper 2022/1208 Original: eprint.iacr.org/2022/1208 ↗

Notes on Reusable Garbling

Abstract

Garbling is a cryptographic primitive which has many applications. It is mainly used for scenes of limited authority, such as multi-party computation (MPC), attribute-based encryption (ABE), functional encryption (FE), indistinguishability obfuscation (IO), etc. Garbling schemes before 2013 are of one-time garbling. Goldwasser et al and Agrawal presented a reusable garbling scheme, which made use of a symmetric encryption scheme and an FE scheme as the components. In this paper we discuss the validity and the efficiency of reusable garbling scheme. We present the following three notes on the scheme. (1) Reusable garbling scheme does not provide new applications, and it is still a one-time garbling scheme. (2) Even reusable garbling scheme is taken as a one-time garbling scheme, sometimes it is not usable. More detailedly, it can only be used for Basic Scene 2, and cannot be used for Basic Scene 1. For example, it cannot be used for MPC. (3) Even reusable garbling scheme is taken as a one-time garbling scheme used for Basic Scene 2, there is no evidence to show that its efficiency is better than a former one-time garbling scheme.