密码组件安全指标测试工具设计与实现

Design and implementation of cipher component security criteria testing tool

对称密码是信息系统中数据保密的核心技术,而非线性S盒通常是其中的关键密码组件,广泛用于分组密码、序列密码和MAC(Message Authentication Code)算法等设计。为了保障密码算法设计的安全性,首先,研究了差分均匀度、非线性度、不动点数、代数次数与项数、代数免疫度、雪崩特性、扩散特性的指标测试方法;其次,通过可视化窗口设计输出S盒的各个安全指标结果,并以弹窗形式给出对应安全指标的细节描述;再次,重点设计了S盒非线性度和代数免疫度的子模块,并对应非线性度简化了线性分布表,且基于定理对代数免疫度计算过程进行了优化和举例说明;最后,实现了S盒的测试工具,并给出了7种安全指标测试和案例演示。所提测试工具主要应用于对称密码算法的非线性组件S盒安全指标的测试,进而为算法整体提供安全保障。

Symmetric cryptography is the core technology of data confidentiality in information systems.At the same time,nonlinear S-box is usually the key cryptographic component,and is widely used in the design of block cipher,stream cipher,MAC(Message Authentication Code)algorithm,etc.In order to ensure the security of the cryptographic algorithm design,firstly,the criteria testing methods for differential uniformity,nonlinearity,fixed point number,algebraic degree and item number,algebraic immunity,avalanche characteristic and diffusion characteristic were researched.Secondly,the results of each security criterion of the S-box were designed and output in the visual window,and the detailed descriptions of the corresponding security criterion were given in a pop-up window way.Thirdly,the design of the sub-components of nonlinearity and algebraic immunity was focused,and the linear distribution table was simplified according to the nonlinearity.At the same time,based on the theorem,the calculation process of algebraic immunity was optimized and illustrated with an example.Finally,the S-box testing tool was implemented with seven security criteria,and the test cases were demonstrated.The proposed tool is mainly used to test the security criteria of the nonlinear component S-box in the symmetric cryptographic algorithm,and then provides a guarantee for the security of the overall algorithm.