An Efficient Structural Analysis of SAS and its Application to White-Box Cryptography
| Title | An Efficient Structural Analysis of SAS and its Application to White-Box Cryptography |
| Publication Type | Conference Paper |
| Year of Publication | 2021 |
| Authors | Yim, Hyoungshin, Kang, Ju-Sung, Yeom, Yongjin |
| Conference Name | 2021 IEEE Region 10 Symposium (TENSYMP) |
| Keywords | composability, cryptography, Encryption, IEEE Regions, Metrics, pubcrawl, resilience, Resiliency, SAS strcuture, security, structural analysis, Synthetic aperture sonar, Table lookup, Time complexity, white box cryptography, White Box Security, white-box |
| Abstract | Structural analysis is the study of finding component functions for a given function. In this paper, we proceed with structural analysis of structures consisting of the S (nonlinear Substitution) layer and the A (Affine or linear) layer. Our main interest is the S1AS2 structure with different substitution layers and large input/output sizes. The purpose of our structural analysis is to find the functionally equivalent oracle F* and its component functions for a given encryption oracle F(= S2 A S1). As a result, we can construct the decryption oracle F*1 explicitly and break the one-wayness of the building blocks used in a White-box implementation. Our attack consists of two steps: S layer recovery using multiset properties and A layer recovery using differential properties. We present the attack algorithm for each step and estimate the time complexity. Finally, we discuss the applicability of S1AS2 structural analysis in a White-box Cryptography environment. |
| DOI | 10.1109/TENSYMP52854.2021.9550967 |
| Citation Key | yim_efficient_2021 |