Low-Delay AES Key Expansion Units Based on DDBT Structure
Xinxing Zheng, Han Yan, Zhiwei Peng, Xiaoqiang Zhang · Electronics · 2025
Advanced Encryption Standard (AES) key expansion unit is usually implemented by chain structure with a long critical path length. That makes key expansion unit become the bottleneck of high-speed AES implementations. In this paper, a design method of low-delay AES key expansion unit is proposed. The proposed design method is based on a delay-drive binary tree (DDBT) structure, which has been proven that it has the shortest critical path length. Based on the proposed design method, a low-delay AES encryption key expansion unit and a low-delay AES encryption/decryption unified key expansion unit are designed in this paper. Both hardware complexity analysis and integrated circuit synthesis indicate that our DDBT-structure-based designs can reduce the delay greatly compared to traditional chain structures. Furthermore, compared to previous works, our designs can achieve the largest throughput.