International Association for Cryptologic Research (IACR)
Doi
Abstract
We construct a simulator for the simulating auxiliary input problem with
complexity better than all previous results and prove the optimality up to
logarithmic factors by establishing a black-box lower bound. Specifically, let
ℓ be the length of the auxiliary input and ϵ be the
indistinguishability parameter. Our simulator is
O~(2ℓϵ−2) more complicated than the distinguisher family.
For the lower bound, we show the relative complexity to the distinguisher of a
simulator is at least Ω(2ℓϵ−2) assuming the simulator is
restricted to use the distinguishers in a black-box way and satisfy a mild
restriction