Paper 2017/267

A Masked White-box Cryptographic Implementation for Protecting against Differential Computation Analysis

Seungkwang Lee

Abstract

Recently, gray-box attacks on white-box cryptographic implementations have succeeded. These attacks are more efficient than white-box attacks because they can be performed without detailed knowledge of the target implementation. The success of the gray-box attack is due to the unbalanced encoding used to generate the white-box lookup table. In this paper, we propose a method to protect the gray-box attack against white-box implementations. The basic idea is to use Boolean masking before encoding intermediate values during the white-box lookup table generation. Compared to the existing white-box AES implementation, the lookup table size and the table lookups increase by about 1.5- and 1.6 times, respectively.