Efficient Software Implementation of ZUC Stream Cipher

Abstract

ZUC stream cipher is the first stream cipher developed independently by Chinese cryptologists as an international standard. The fast implementation of encryption algorithm is an important issue in cryptography application. At present, the research on ZUC stream cipher is mainly based on hardware implementation, and there are many efficient hardware implementations of ZUC stream cipher, but there are few efficient software implementations at present. This paper presents an efficient software design and implementation of ZUC stream cipher. Firstly, we propose the delayed modular, sliding window, and S-box optimizations to reduce the computational cost without modifying the calculation result of ZUC stream cipher. Secondly, single instruction multiple data instructions, reducing the times of memory access, loop unrolling optimization and other code optimization methods can improve the speed of encryption and decryption. Finally, we design and implementation a genetic algorithm to find the optimal sequence of optimizations in compiler. Experiments show that compared with the implementation of ZUC stream cipher given in the official document, these methods can give 102% performance improvement.