J4 ›› 2010, Vol. 37 ›› Issue (6): 1017-1021.doi: 10.3969/j.issn.1001-2400.2010.06.007

• 研究论文 • 上一篇    下一篇

一种提高S盒非线性度的新算法

高胜;马文平;郭娜;严亚俊   

  1. (西安电子科技大学 计算机网络与信息安全教育部重点实验室,陕西 西安  710071)
  • 收稿日期:2009-11-04 出版日期:2010-12-20 发布日期:2011-01-22
  • 通讯作者: 高胜
  • 作者简介:高胜(1982-),男,西安电子科技大学博士研究生,E-mail: gaosheng@mail.xidian.edu.cn.
  • 基金资助:

    国家863计划资助项目(2007AA01Z472);国家自然科学基金资助项目(60773002,61072140);教育部留学回国人员科研启动基金资助项目;高等学校创新引智计划资助项目(B08038)

Novel method for increasing the nonlinearity of S-Boxes

GAO Sheng;MA Wen-ping;GUO Na;YAN Ya-jun   

  1. (Ministry of Education Key Lab. of Computer Network and Information Security,
  • Received:2009-11-04 Online:2010-12-20 Published:2011-01-22
  • Contact: GAO Sheng

摘要:

S盒是构成分组密码算法重要的非线性部件.利用交换S盒两个输出向量来达到提高其非线性度的思想,提出一个通过交换S盒3个输出向量来提高其非线性度的方法,即三点爬山法.该方法简洁且执行效率较高,而且在William Millan两点爬山法不能提高S盒非线性度的情况下,能进一步改进非线性度.在此基础上,提出一个基于爬山算法的S盒优化算法,弥补了原有算法不能进一步改善非线性度的缺陷.对一些小变量S盒的实验结果验证了该算法的正确性和高效性.

关键词: S盒, 非线性度, Walsh变换, 爬山算法

Abstract:

An S-box is an important nonlinear component of block cipher algorithms.Using the idea of swapping two output vectors to increase nonlinearity of the S-Boxes, we propose a method for improving the nonlinearity by swapping three output vectors, namely, a new three-point hill-climbing algorithm.This method is simple and more efficient in implementation. Moreover, it could further improve the nonlinearity when William Millan's two-point hill-climbing could not. On the basis of this, an optimization algorithm based on the hill-climbing algorithm for improving the nonlinearity of the S-Boxes is presented, which overcomes the disadvantage of existing algorithms that cannot improve the nonlinearity further. Numerical results of testing for some small variables S-Boxes show the correctness and efficiency of the proposed algorithm.

Key words: S-Boxes, nonlinearity, Walsh transformation, hill-climbing algorithm