Novel quantum circuit implementation of Advanced Encryption Standard with low costs

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2022-09, Vol.65 (9), p.290311, Article 290311
• Main Authors: Li, ZhenQiang, Cai, BinBin, Sun, HongWei, Liu, HaiLing, Wan, LinChun, Qin, SuJuan, Wen, QiaoYan, Gao, Fei
• Format: Article
• Language: English
• Subjects: Astronomy; Circuits; Classical and Continuum Physics; Observations and Techniques; Physics; Physics and Astronomy; Qubits (quantum computing)
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-022-1921-y

In this study, we examine how the quantum circuit of the Advanced Encryption Standard (AES) can be optimized from two aspects, i.e., number of qubits and T -depth. To reduce the number of qubits, we present three kinds of improved quantum circuits of S-box for different phases in the AES. We found that the number of qubits in the round function can be decreased by introducing the circuit sending | a 〉 to | S ( a )〉. As a result, compared with the previous quantum circuits where 400/640/768 qubits are required, our circuits of AES-128/-192/-256 only require 270/334/398 qubits. To reduce the T -depth, we propose a new circuit of AES’s S-box with a T -depth of 4. Accordingly, the T -depth of our AES-128/-192/-256 quantum circuits become 80/80/84 instead of 120/120/126 in a previous study.