密码函数是对称密码学中的一个重要研究内容，本项目主要研究具有Niho型指数的非线性密码函数。具体地，结合Niho型指数的特点，运用代数等工具研究Niho型Bent函数和半Bent函数的构造；探索Niho型低差分置换多项式的构造方法以及特殊形式Niho型函数Walsh谱值的新计算方法。通过对具有Niho型指数函数的研究以期望构造出参数多样、性能优良的密码函数，为对称密码提供更多可供选择的优良非线性部件候选函数。因此本项目具有重要的理论意义和实际价值。

The cryptographic functions are an important research topic in symmetric cryptography and this project mainly studies the nonlinear cryptographic functions with Niho-type exponents. Concretely, by using the property of Niho-type exponents and applying mathematical tools such as algebra, this project aims to explore new constructions of Niho-type Bent and semibent functions and Niho-type permutation polynomials with low differential property as well as to find new methods of computing the Walsh spectra of Niho-type functions with special forms. The objective of this project is to provide more nonlinear candidate functions for symmetric cryptography by constructing cryptographic functions with diverse parameters and excellent properties, and it is therefore of theoretical and practical significance.