| 摘要: |
| FBC分组密码算法是入选2018年全国密码算法设计大赛第2轮的10个分组密码算法之一. FBC主要采用四分支两路Feistel结构设计, 是一个实现效率高的轻量级分组密码算法. 将FBC算法抽象为FBC模型, 并研究该模型的伪随机性和超伪随机性, 在FBC轮函数都是相互独立的随机函数的条件下, 给出能够与随机置换不可区分所需的最少轮数. 结论表明, 在选择明文攻击条件下, 4 轮FBC与随机置换不可区分, 因而具有伪随机性; 在自适应性选择明密文攻击条件下, 5轮FBC与随机置换不可区分, 因而具有超伪随机性. |
| 关键词: 分组密码 FBC模型 伪随机性 超伪随机性 |
| DOI：10.13328/j.cnki.jos.006957 |
| 分类号:TP309 |
| 基金项目:河南省优秀青年科学基金(222300420100); 国家自然科学基金(61772547) |
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| Pseudorandomness and Super-pseudorandomness of FBC Model |
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LIU Nan1, JIN Chen-Hui1, YU Jun-Wei2, CUI Ting1
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1.PLA SSF Information Engineering University, Zhengzhou 450001, China;2.School of Artificial Intelligence and Big Data, Henan University of Technology, Zhengzhou 450001, China
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| Abstract: |
| As one of the ten block cipher algorithms selected for the second round of the 2018 National Cryptographic Algorithm Design Contest, Feistel-based block cipher (FBC) is an efficient and lightweight block cipher algorithm with a four-branch and two-fold Feistel structure. In this study, the FBC algorithm is abstracted as the FBC model, and the pseudorandomness and super-pseudorandomness of the model are studied. It is assumed that the FBC round functions are independent random functions, and a method to find the minimal number of FBC rounds is provided, which will keep FBC indistinguishable from a random permutation. Finally, the study comes to the conclusion that under the chosen-plaintext attack, four rounds of FBC are indistinguishable from random permutation, so the model has pseudorandomness; under the adaptive chosen-plaintext and ciphertext attack, five rounds of FBC are indistinguishable from random permutation, so the model has super-pseudorandomness. |
| Key words: block cipher FBC model pseudorandomness super-pseudorandomness |
