The development of new disciplines in the field of mathematics lies in promoting research on encryption technology and cryptography. The semi-tensor product

a new mathematical tool

is a generalization of the traditional matrix multiplication; it provides a new approach by which high-dimensional matrix digital signal processing can achieve a different dimension. In this paper

a novel image-encryption algorithm based on the semi-tensor product is proposed. The content of the plaintext is used as a key parameter. Then

a small reversible key matrix is constructed by using the Kronecker product; the key matrixis then used 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 those of the key matrix. Experiments are performed by using an 8×8 key matrix featuring images of various sizes. After comparing the experimental results with those of previous methods

the proposed method demonstrated a high level of security with a suitable processing performance. A small encryption matrix is proposedto encrypt and decrypt images

wherein the dimensions of the original image are larger thanthose of the key matrix. The computations of the data are effectively reduced

and the operational efficiency of the encryption process is enhanced. The experimental results also demonstrate that the proposedalgorithm offers secure information protection and satisfies the processing time required by standard applications.