Construction of RSBFs with Optimal Algebraic Immunity on Even Variables

As an important technology for protecting data confidentiality and user privacy, block ciphers are widely used in machine learning. In block ciphers, since data is divided into fixed-size blocks, block ciphers can efficiently process large amounts of data and have relatively fast encryption and decryption speeds. Boolean functions is a core component in the design of block ciphers, and algebraic immunity is a key criterion in the design of Boolean functions, and the quality of algebraic immunity can assess the ability of cryptographic algorithms to against algebraic attacks. Rotation Symmetric Boolean Functions (RSBFs) has a special construction that have attracted particular attention in cryptography due to their good cryptographic properties, such as the optimal algebraic immunity and high nonlinearity. In this paper, we construct a RSBFs based on the majority function by modifying its support. And ensure that it has the optimal algebraic immunity, the nonlinearity has also been improved.