A quantum color image encryption algorithm based on geometric transformation and intensity channel diffusion was designed. Firstly, a plaintext image was transformed into a quantum state form using the quantum image representation based on HSI color space (QIRHSI) representation as a carrier. Next, a pseudo-random sequence was generated using the generalized logistic map, and the pixel positions permuted multiple two-point swap operations. Immediately afterward, the intensity values were changed by an intensity bit-plane cross-swap and XOR, XNOR operations. Finally, the intensity channel of the above image was diffused in combination with the pseudo-confusion sequence as produced by the quantum logistic map to perform a diffusion operation on the intensity bit-plane to obtain the ciphertext image. Numerical simulations and analyses show that the designed algorithm is implementable and robust, especially in terms of outstanding performance and less computational complexity than classical algorithms in terms of security perspective.
A quantum color image encryption algorithm based on geometric transformation and intensity channel diffusion was designed. Firstly, a plaintext image was transformed into a quantum state form using the quantum image representation based on HSI color space (QIRHSI) representation as a carrier. Next, a pseudo-random sequence was generated using the generalized logistic map, and the pixel positions permuted multiple two-point swap operations. Immediately afterward, the intensity values were changed by an intensity bit-plane cross-swap and XOR, XNOR operations. Finally, the intensity channel of the above image was diffused in combination with the pseudo-confusion sequence as produced by the quantum logistic map to perform a diffusion operation on the intensity bit-plane to obtain the ciphertext image. Numerical simulations and analyses show that the designed algorithm is implementable and robust, especially in terms of outstanding performance and less computational complexity than classical algorithms in terms of security perspective.
In this paper, a quantum image encryption scheme is proposed by using the inter–intra bit-level permutation strategy. The image to be encrypted is first represented by a novel enhanced quantum representation model, and then, the intra and inter permutation operations are successively performed on bit planes. The intra bit permutation is achieved by sorting chaotic sequence, and the inter bit permutation is accomplished with qubit XOR operations between the two selected bit planes. The ciphertext image is finally obtained through a chaotic diffusion procedure implemented with a quantum image XOR operation. The XOR operation is realized by controlled- NOT gates, which is controlled by a chaotic sequence generated with a logistic map. The parameters of the logistic map are sensitive, which makes the key space large enough to resist brute-force attack. The proposed scheme not only modifies the pixel positions and gray values but also makes the bit distribution more uniform. The quantum circuits for the proposed encryption algorithm are devised. The simulation results and theoretical analysis show that the proposed method is more efficient than its classical counterpart, and its security is verified by the statistical analysis, keys sensitivity, and key space analysis.
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 Data encryption is one of the main factors in their transmission. In this paper, we have described an algorithm for color image encryption, some quantum encryption and image scrambling operations will be performed based on bitplane representation of quantum images (BRQI). Next, the image created using the logistic map (key image) is blended with the output of the first step, which was possible with the help of a quantum comparator circuit. Finally we create a secure image as the output of the encryption algorithm. Experiments with simulation and analysis of parameters such as entropy and correlation coefficient of adjacent pixels in three main positions show that the proposed algorithm has been very efficient and effective in securing and encrypting color images.
In order to further improve the security and efficiency of quantum image encryption, a three-layer encryption scheme for quantum color images based on 6D hyperchaos is proposed for the improved quantum representation model. The sequences generated by the 6D hyperchaotic system are applied to each layer of image encryption as keys. First, the quantum Fibonacci matrix is used to scramble the pixel value positions of the image to achieve the spatial scrambling of the quantum image; then, the position exchange of red, green, and blue channels and the bit-level cycle shift of pixel value are carried out alternately to realize the bit-level scrambling of quantum images; Finally, the XOR operation is performed on the quantum image whose position has been scrambled to realize the bit-level diffusion of the quantum image and obtain the final encrypted image. Simulation results show that the encryption algorithm is highly sensitive to the initial key, and the pixel values of the encrypted image are evenly distributed. In addition, quantum circuits are designed to implement the image encryption steps of each layer.
The advent of quantum computers could enable the resolution of complex computational problems that conventional cryptographic protocols find challenging. As a result, the formidable computing capabilities of quantum computers may render all present-day cryptographic schemes that rely on computational complexity ineffectual. Inspired by these possibilities, the primary purpose of this paper is to suggest a quantum image encryption scheme based on quantum cellular automata with mixed multi-chaos hybrid maps and a hyperchaotic system with quantum operations. To achieve desirable encryption outcomes, we designed an encryption scheme involving two main operations: (1) pixel-level diffusion and (2) pixel-level permutation. Initially, the secret keys generated using the hyperchaotic system were closely tied to the original image. During the first phase, the establishment of correlations among the image pixels, in addition to the three chaotic sequences obtained from the hyperchaotic system, was achieved with the application of a quantum-state superposition and measurement principle, wherein the color information of a pixel is described using a single qubit. Therefore, the three channels of the plain image were subjected to quantum operations, which involve Hadamard transformation and the quantum-controlled NOT gate, before the diffusion of each color channel with the hyperchaotic system. Subsequently, a quantum ternary Toffoli gate was used to perform the diffusion operation. Next, the appropriate measurement was performed on the three diffused channels. To attain the confusion phase, a blend of mixed multi-chaos hybrid maps and a two-dimensional quantum cellular automaton was used to produce random and chaotic sequence keys. Subsequently, the circular shift was utilized to additionally shuffle the rows and columns of the three diffused components, in order to alter the positions of their pixel values, which significantly contributes to the permutation process. Lastly, the three encoding channels, R, G, and B, were merged to acquire the encrypted image. The experimental findings and security analyses established that the designed quantum image encryption scheme possesses excellent encryption efficiency, a high degree of security, and the ability to effectively withstand a diverse variety of statistical attacks.
In order to improve the security of traditional encryption systems, hyper-chaotic systems are introduced into the field of quantum image encryption. Firstly, the image is bitwise XOR by He fractional order hyper-chaotic Rabinovich system, and then the color image is represented as a quantum superposition state. The quantum image is scrambled by the unitary matrix generated by Logistic hyper-chaotic sequence, and then a hyper-chaotic sequence is generated to randomly replace the red, green and blue primary colors of each pixel to achieve the purpose of quantum image encryption. Finally, numerical simulation experiments are carried out on a computer. The experimental results show that the histogram of the encrypted image is flatter and even, the pixels are evenly distributed between 0 and 255, the correlation between adjacent pixels of the image is low. The average correlation coefficients of the red, green, and blue pixels of the encrypted image are 0.0012, 0.0025, and 0.0018. The system has high key sensitivity and can effectively resist statistical analysis attacks. The algorithm has good security and robustness.