Efficient quantum circuit implementation of the SM4 S-box
LIU JiaHong, Xiaoqing Tan, LI Ming, BAO DaiPengWei · Zhongguo kexue. Wulixue Lixue Tianwenxue · 2023
In recent years, the quantum circuit implementation in symmetric cryptography has attracted widespread attention. The SM4 block cipher algorithm is China's first commercial cipher standard and was accepted as an ISO/IEC international standard in 2021. S-box is the most complex component in the SM4 block cipher algorithm. This study investigates the quantum circuit implementation of the SM4 S-box. Based on the algebraic structure, using tower filed decomposition technology, the quantum circuit of the SM4 S-box is built. Based on the number of NCT gate sets, our quantum circuit requires 20 qubits, 52 Toffoli gates, 196 CNOT gates, and 13 X gates. The Toffoli depth of our circuit is 36. Compared with previous literature, the quantum circuit proposed herein requires fewer quantum resources.