Cryptology ePrint Archive: Report 2021/042

Correcting Subverted Random Oracles

Alexander Russell and Qiang Tang and Moti Yung and Hong-Sheng Zhou and Jiadong Zhu

Abstract: The random oracle methodology has proven to be a powerful tool for designing and reasoning about cryptographic schemes. In this paper, we focus on the basic problem of correcting faulty—or adversarially corrupted—random oracles, so that they can be confidently applied for such cryptographic purposes.

We prove that a simple construction can transform a “subverted” random oracle—which disagrees with the original one at a small fraction of inputs—into an object that is indifferentiable from a random function, even if the adversary is made aware of all randomness used in the transformation. Our results permit future designers of cryptographic primitives in typical kleptographic settings (i.e., those permitting adversaries that subvert or replace basic cryptographic algorithms) to use random oracles as a trusted black box.

Category / Keywords: foundations / kleptography, cliptography, random oracles, indifferenttiability

Original Publication (with major differences): IACR-CRYPTO-2018

Date: received 11 Jan 2021

Contact author: qtang84 at gmail com,jiadong zhu@uconn edu

Available format(s): PDF | BibTeX Citation

Version: 20210112:131524 (All versions of this report)

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