Efficient public-key operation in multivariate schemes

Abstract

The public-key operation in multivariate encryption and signature schemes evaluates \begin{document}$ m $\end{document} quadratic polynomials in \begin{document}$ n $\end{document} variables. In this paper we analyze how fast this simple operation can be made. We optimize it for different finite fields on modern architectures. We provide an objective and inherent efficiency measure of our implementations, by comparing their performance with the peak performance of the CPU. In order to provide a fair comparison for different parameter sets, we also analyze the expected security based on the algebraic attack taking into consideration the hybrid approach. We compare the attack's efficiency for different finite fields and establish trends. We detail the role that the field equations play in the attack. We then provide a broad picture of efficiency of MQ-public-key operation against security.