Optimized implementations of stream cipher ZUC-256 algorithm

ZUC-256 is a more secure stream cipher based on ZUC-128 developed independently by China, which emerged mainly to cope with the advent of 5G communication and the post-quantum cipher era. Based on the ZUC-256 encryption algorithm, this paper focuses on its working phase and proposes two optimization methods for the working phase, one is a pipelined structure that focuses more on increasing the frequency, and the other is based on the specificity of the modulo operation in the algorithm, which focuses on reducing the resource overhead. The final validation results show that the first method increased frequency by 37.2% and the second method reduced resource overhead by 18.7%. These two optimization methods show that the ZUC algorithm is quite flexible in balancing different throughputs with resource overheads.