改进的广义Feistel结构轻量级分组密码算法

Lightweight block cipher algorithm based on the improved generalized Feistel structure

中文关键词  分组密码算法  广义Feistel结构  ARX结构

英文关键词  block cipher algorithm  generalized Feistel structure: ARX structure

中文摘要

      随着复杂环境信息物理系统的更加开放, 数据的安全传输问题备受关注. 轻量级分组密码算法是保证信息 物理系统数据安全传输的重要方法之一, 但其仍存在软件实现速率低、硬件实现复杂和灵活性缺乏等问题. 针对上 述问题, 提出了一种基于四分支的广义Feistel结构的高性能轻量级分组密码算法. 相较于传统的广义Feistel结构算 法, 该算法进行了以下优化: 1) 采用由模加、循环位移和异或3种操作组合成的ARX (modular addition, rotation and XOR)结构替换传统广义Feistel结构中的S盒(非线性替换层)和P盒(线性置换层), 简化了算法的轮函数结构; 2) 增加 非对称双子密钥以处理每轮加密的明文中间状态, 使得中间状态不存在未处理的分支, 提高了算法的安全性; 3) 设 计了可扩展的轮常数加模块, 提高了算法的灵活性; 4) 分支中增加混淆扩散结构fx, 加快了算法的混淆和扩散速度; 5) 灵活设计了6个版本的轻量级分组密码算法, 以适应不同位数的CPU平台. 实验和分析表明, 该算法实现效率高, 具有良好的混淆和扩散能力, 以及较高的安全性.

英文摘要

      With the openness of cyber-physical systems (CPS) in complex environments, the issue of data secure transmission has attracted much attention. Lightweight block cipher algorithm is one of the important methods to ensure the secure transmission of data in CPS, but it still has problems such as low software implementation rate, complex hardware implementation, and lack of flexibility. To solve such problems, a high-performance lightweight block cipher algorithm based on the four-branch generalized Feistel structure is proposed. Compared with the traditional generalized Feistel structure, the algorithm has the following advantages: 1) Combined by three simple operations of modular addition, rotation and XOR, ARX structure is used to replace the traditional generalized Feistel the S-box (non-linear replacement layer) and P-box (linear replacement layer) in the structure which simplifies the round function structure of the algorithm; 2) Adding an asymmetric dual key to process the intermediate state of the plaintext in each round of encryption, so that the intermediate state has no unprocessed branch, which improves the security of the algorithm; 3) An expandable round-constant plus module is designed to improve the flexibility of the algorithm; 4) The structure fx is added to the branch to speed up the confusion and the diffusion speed of the algorithm; 5) To adapt to the CPU platforms, six versions of lightweight block cipher algorithms are designed. Experiments and analysis show that the algorithm has high efficiency, good confusion and diffusion capabilities, and high security.