The benefit of using chaos in key schedule algorithm

作     者：Harmouch, Youssef El Kouch, Rachid 

作者机构：INPT Lab Multimedia Signal & Commun Syst Dept Math Comp & Networks Rabat Morocco 

出 版 物：《JOURNAL OF INFORMATION SECURITY AND APPLICATIONS》 (J. Inf. Secur. Appl.)

年 卷 期：2019年第45卷

页      面：143-155页

核心收录：

学科分类：08[工学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

主　　题：Logistic maps Key schedule algorithm Weak-key Independent sub-key One-way function 

摘      要：Many ciphers suffer from weak-key issues. This problem is due to the simplicity of the key schedule algorithm. Unfortunately, the cipher designers have not paid much attention to the sub-keys generation as the cipher itself. Thus, any attacker can find many attractive properties between sub-keys such as statistical pattern, linearity, low avalanche criteria, etc. Many ciphers use a large key during encryption (e.g. 128 bits). This makes it practically impossible to test all keys, allowing all of today s ciphers to be potentially vulnerable to the weak-key issue, including AES. Accordingly, this paper sheds light on the advantage of using chaos in sub-keys generation by developing a new key schedule algorithm based on the logistic maps. We name this algorithm CKSA. Compared to several existing key schedule algorithm, CKSA provides a good avalanche effect. It is a one-way function, and its size is flexible, i.e. the size of the sub-keys is not fixed, which allows to many ciphers the possibility of using it. Further, CKSA ensures confusion and diffusion. It resists differential attacks and avoids linear key correlation between sub-keys while ensuring a high degree of randomization among them. (C) 2019 Elsevier Ltd. All rights reserved.