2021/08/24 by Yangpan Zhang, Zhang, Yangpan, Maozhi Xu +1
Computer Science · Mathematics · #Cryptography and Security (cs.CR) #FOS: Computer and information sciences #Information Theory (cs.IT) #cs.CR #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.2108.10770
18 pages, 1 figures. This paper was accepted by inscrypt2021(The 17th International Conference on Information Security and Cryptology)
arxiv created 2021/08/24 · arxiv updated 2021/08/25
As a research field of stream ciphers, the pursuit of a balance of security and practicality is the focus. The conditions for security usually have to satisfy at least high period and high linear complexity. Because the feedforward clock-controlled structure can provide quite a high period and utility, many sequence ciphers are constructed based on this structure. However, the past study of its linear complexity only works when the controlled sequence is an m-sequence. Using the theory of matrix over the ring and block matrix in this paper, we construct a more helpful method. It can estimate the lower bound of the linear complexity of the feedforward clock-controlled sequence. Even the controlled sequence has great linear complexity.