Protecting the Unbalanced Oil and Vinegar Signature Scheme against Side-channel Attack

Abstract

With the recent development of quantum computing, there is an urge for Post- Quantum Cryptography(PQC). The National Institute of Standards and Technology( NIST) initiated a public process to standardize PQC algorithms to address this issue in 2016. To search for new signature schemes with diverse hardness problems, short signature sizes and fast verification, NIST called for additional digital signature schemes for the PQC in 2022. Based on multivariate cryptography, the Unbalanced Oil and Vinegar(UOV) signature scheme is a candidate for this additional round. This scheme has stood out for two decades of cryptanalysis and has a short signature size and fast verification. We believe this is a potential candidate for this round. As usual, this scheme is mainly designed to resist mathematical attacks; however, deploying this scheme in an actual device leaks unintended information through side-channels such as power consumption. Side-channel analysis helps to exploit those unintended information and recover the secrets of the scheme. Recently, a few attacks have been shown using correlation power analysis in this scheme. Masking is a well-known and provably secure countermeasure against such attacks. In this thesis, we describe the first masked implementation of the UOV scheme. We also produce security proof of our implementation in the probing model.