In this work, a new approach to image encryption is proposed. This crypto system is composed of two stages of the Hill cipher. First, a passage in vector of the original image is carried out, followed by a subdivision in blocks of three pixels, then, an invertible (3×3) order matrix is generated from the chaotic maps will be used for implementation an encryption process based on an affine transformation. Finally, another complete order matrix (3×3) not necessarily invertible is used to install a diffusion phase using a new mode enhancement (CBC) whose purpose is to protect our approach against any differential attack. Simulations on a large number of images prove that our algorithm has excellent security performance.