Partial image encryption for smart camera

Smartness of camera can be increased by adding extra feature to it. Selective encryption employs portion of original image in encryption process, but there is no control over amount of encryption. Novelty of this proposed two-stage Hill cipher method includes selection of square blocks to manipulate self invertible matrix. Which leads to control the amount of encryption with step size of 12.5% with respect to number of pixel changing rate (NPCR). This paper describes the lossless partial image encryption in two ways. First method uses two-stage Hill cipher to produce partially encrypted image. Here Latin Square Image Cipher technique is used to generate basic block of self invertible matrix which is used in hill cipher. Second method uses four stage Hill cipher (Two two-stage Hill cipher) to produce partially encrypted image. Decryption follows the reverse process of encryption. The analysis and experimental results show that the proposed scheme can achieve the concept of partial encryption.