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.
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.
Quantum image encryption offers major advantages over its classical counterpart in terms of key space, computational complexity, and so on. A novel double quantum image encryption approach based on quantum Arnold transform (QAT) and qubit random rotation is proposed in this paper, in which QAT is used to scramble pixel positions and the gray information is changed by utilizing random qubit rotation. Actually, the independent random qubit rotation operates once, respectively, in spatial and frequency domains with the help of quantum Fourier transform (QFT). The encryption process accomplishes pixel confusion and diffusion, and finally the noise-like cipher image is obtained. Numerical simulation and theoretical analysis verify that the method is valid and it shows superior performance in security and computational complexity.
In the wake of the information security era, ensuring the privacy, accuracy, and reliability of images has become imperative. In this paper, a quantum image encryption method combining quantum Arnold transform and a hyper 5D chaotic system is devised. Furthermore, first, a nonlinear color quantization model (NCQI) is used to convert digital images in standard RGB format into quantum color images. Then, based on the size of the converted quantum color image, the corresponding encryption key is generated using the hyper 5D chaotic system. In the encryption stage, we use the key to encrypt the converted quantum color image. This process entails two principal steps: First, we use quantum Arnold transform to scramble the pixel positions in the image and, subsequently, diffuse the pixel values through a carefully designed cyclic shift strategy to achieve the preliminary encryption of the image. To further strengthen the encryption security, we use a quantum rotation gate to perform quantum rotation transformation on the color channel of each pixel point in the encrypted image separately. These well-designed encryption processes, in succession, significantly enhance the security of the image. This paper provides the corresponding quantum circuit design and validates both the efficacy and security of the quantum image encryption scheme through simulation experimental results.
Background: Quantum image processing is rapidly developing in the field of quantum computing, and it can be successfully implemented on the Noisy Intermediate-Scale Quantum (NISQ) device. Quantum image encryption holds a pivotal position in this domain. However, the encryption process often encounters security vulnerabilities and entails complex computational complexities, thereby consuming substantial quantum resources. To address this, the present study proposes a quantum image encryption algorithm based on four-dimensional chaos. Methods: The classical image is first encoded into quantum information using the Generalized Quantum Image Representation (GQIR) method. Subsequently, the trajectory of the four-dimensional chaotic system is randomized, and multi-dimensional chaotic keys are generated to initially encrypt the pixel values of the image. Then, the Arnold transformation is applied to randomly encrypt the pixel positions, resulting in the encrypted image. During the decryption process, the inverse process of encryption is employed to restore the original image. Results: We simulated this process in the Python environment, and the information entropy analysis experiment showed that the information entropy of the three encrypted images reached above 7.999, so the system has good encryption. At the same time, the correlation of the pixel distribution after the encryption algorithm is weak, which proves that the control parameters of the chaotic system can effectively reduce the correlation between pixels in the image. In the final key space analysis, the key space issued by our encryption can reach $10 140 \gg 2 128 $. Conclusion: Our method is resistant to destructive attacks and can produce scrambled images with higher encryption and usability. This algorithm solves the problems of general encryption algorithms such as periodicity, small key space, and vulnerability to statistical analysis, and proposes a reliable and effective encryption scheme. By making full use of the characteristics of Arnold transformation permutation, ergodicity and the randomness of the four-dimensional chaotic system, the encryption algorithm uses the larger key space provided by the four-dimensional Lorenz system.
Abstract The parallel computing power of quantum computing and the special properties of qubits provide an effective solution for image processing tasks. This paper presents a quantum image encryption algorithm based on Fisher-Yates algorithm and Logistic mapping. Firstly, the Fisher-Yates algorithm is used to generate three key sequences, one of which is used to encode the coordinate qubits of the image. Using the other two keys and the preset rules, the quantum coordinate scrambling operation is designed based on the encoded coordinate qubit, which effectively scrambles the spatial information of the plaintext image. Next, another set of key sequences is generated, one of which is used to encode the color qubits of the image. Using two other key sequences and different rules, a qubit plane scrambling operation based on coded color qubits is designed, and the color information of image is scrambled successfully. Finally, the quantum key image is generated based on Logistic mapping, and the key image is scrambled based on Fisher-Yates algorithm to improve the key complexity. The final ciphertext image is obtained by performing XOR operation between the original image and the scrambled key image. The complete quantum circuit diagram of the scheme is given in this paper. The experimental results and security analysis prove the effectiveness of the scheme, which provides a large key space and the computational complexity is only O(n).
Abstract In the field of Internet, an image is of great significance to information transmission. Meanwhile, how to ensure and improve its security has become the focus of international research. We combine DNA codec with quantum Arnold transform (QArT) to propose a new double encryption algorithm for quantum color images to improve the security and robustness of image encryption. First, we utilize the biological characteristics of DNA codecs to perform encoding and decoding operations on pixel color information in quantum color images, and achieve pixel-level diffusion. Second, we use QArT to scramble the position information of quantum images and use the operated image as the key matrix for quantum XOR operations. All quantum operations in this paper are reversible, so the decryption operation of the ciphertext image can be realized by the reverse operation of the encryption process. We conduct simulation experiments on encryption and decryption using three color images of “Monkey”, “Flower”, and “House”. The experimental results show that the peak value and correlation of the encrypted images on the histogram have good similarity, and the average normalized pixel change rate (NPCR) of RGB three-channel is 99.61%, the average uniform average change intensity (UACI) is 33.41%, and the average information entropy is about 7.9992. In addition, the robustness of the proposed algorithm is verified by the simulation of noise interference in the actual scenario.
In order to improve the security of quantum color images, this study proposes a novel algorithm for quantum color image encryption based on three-dimensional chaotic systems. The encrypted quantum color image is represented by the novel quantum image representation for color digital image model. The original image is first perturbed by the Arnold transform and then the RGB channel is perturbed separately from the chaotic sequence generated by the new three-dimensional chaotic system by the xor operation. Evaluation metrics such as histogram, information entropy, and correlation of neighboring pixels of the image are analyzed using MATLAB. The simulation results show that the pixel values of the encrypted image are uniformly distributed and the algorithm enhances the security of quantum color images. The specific quantum circuit diagram of the encryption algorithm is given in the paper. The superposition and entanglement properties of quantum physics greatly improve the efficiency of complex image processing algorithms, and the overall complexity of the circuit is O(n), which is efficient and implementable.