Novel quantum circuit implementation of Advanced Encryption Standard with low costs

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 of120/120/126 in a previous study.