A novel symmetric image encryption approach based on an invertible two-dimensional map

This paper proposes a new invertible two-dimensional map, called Line map, for image encryption and decryption. It maps an image to an array of pixels and then, maps it back from the array to a same sized image. A Line map consists of two submaps: the left Line map and the right Line map, which are used for image encryption and decryption. In order to overcome the shortcoming of conventional image encryption approaches based on two-dimensional (2-D) maps which can be used only for permutation, this paper presents a novel image encryption approach based on the Line maps, which can perform two processes of image encryption simultaneously, permutation and substitution, using the same maps. The proposed image encryption does not have information loss. Other advantages include that it is fast and there is no restriction on the length of security key that is desirable for different security requirements. Simulation results show the effectiveness of the new image encryption scheme.