Design and Implementation of Color Image Encryption Based on Qubit Rotation About Axis

Abstract

Currently, almost all color image encryption/decryption algorithms are designed based on a classical computer, in which the key space is relatively small, and the huge gains from quantum parallelism are not obtained. To address this problem, we propose a novel color image encryption/decryption method based on random rotation of qubit and Quantum Fourier transform (QFT). First, the color image is represented in a quantum superposition state |Image⟩, in which the color information of each pixel is described by only one qubit |c⟩. Then, the |c⟩ are randomly rotated on the Bloch sphere about three coordinate axis, and the QFT is performed on the |Image⟩. Once again, the |c⟩ is randomly rotated on the Bloch sphere and then the inverse QFT is performed on the |Image⟩, which the encryption process is implemented. The keys are the rotation angles of two above-mentioned rotations. The decryption is the inverse process of the encryption. Our method may run on a quantum computer in the future. The simulation results on the classic computer show that our approaches have better security.