Quantum Circuit Design of RECTANGLE Lightweight Cipher

Quantum computers will have a significant impact on the security aspects of many conventional cryptographic algorithms as the quantum circuit implementation of the cryptographic algorithms can be attacked with the help of Grover’s key search algorithm. This work proposes quantum circuit design of RECTANGLE lightweight cipher for 80-bit and 128-bit key variants. All the individual modules of the cipher are designed with minimal quantum resources and finally they are integrated together to build the complete quantum circuit. The quantum circuit synthesis is performed with Toffoli family of quantum gates. The proposed design outperforms the existing design by achieving low-latency. The quantum resources are also estimated to mount the quantum attack by using Grover’s key search algorithm.