Faster Image Encryption: A Semi-Tensor Product Approach

Due to the large-scale of the images, they suffer from a long time to finish the process of encryption and decryption. In this paper, we propose a novel image-encryption algorithm to improve the performance of processing time based on the semi-tensor product (STP). The STP is a novel matrix product that works by extending the conventional matrix product in cases of unequal dimensions. In paper, we construct a small reversible key matrix by using the Kronecker product. Then, we use this key matrix to change the values of pixels in the original image by applying the semi-tensor product. As a result, the dimensions of the original image are much larger than the dimensions of the key matrix, and the amount of data that is calculated during the encryption and decryption process is effectively reduced. Meanwhile, the proposed algorithm can be used to encrypt and decrypt images of different sizes. Experiments were carried out using images of various sizes. The experimental results were compared with previous methods and the proposed method outperformed the others in terms of security and processing time.