Abstract: Cryptography is very important in the information security area.Many problems in the cryptology can be represented as optimizationproblems in mathematics.This paper applies Particle Swarm Optimization(PSO) algorithm in the cryptology area to design Boolean function in cryptography.According to the original thought of the PSO algorithm，this paper imports swap operator and swap sequence concept，designs the PSO algorithm which can search directly on the discrete domain.By the improved method，it is easy to automatically design Boolean function which satisfies hign non-linearity and low autocorrelation to construct more securely cipher.Compared with the general mathematic construction method，this method has the superiority in automatic design and more effectively.

Key words: information security, cryptography, Boolean function, Particle Swarm Optimization(PSO)

摘要： 密码学在信息安全显得非常重要。密码学中的大量问题在数学上可以表现为困难的优化问题。将粒子群(Particle Swarm Optimization，PSO)算法应用于密码学领域，设计密码学中的密码函数—布尔函数。根据PSO算法的基本思想，引入交换子和交换序概念，设计出可以直接在离散领域进行搜索的PSO算法，自动化设计高非线性度、低自相关免疫性的密码函数，从而构造更安全的密码。与数学构造方法相比，该方法具有设计自动化、高效的优点。

关键词: 信息安全, 密码学, 布尔函数, 粒子群