A high_performance steganographic method using JPEG and PSO algorithm

In this paper, we present a novel method to embed secret message in the cover-image so that the interceptors will not notice about the existence of the hidden data. The basic concept of the proposed method is by simple Least Significant Bit (LSB) substitution. In order to improve the quality of stego-image and to increase the secret message capacity and security level, we inspire by the work of Li and Wang which splits the cover-image into n blocks of 8 times 8 pixels and the secret message into n partitions. Then we apply Particle Swarm Optimization (PSO) algorithm to search approximate optimal solutions and to find an optimal substitution matrix for transforming the secret message in each block, instead of finding only one optimal substitution matrix for the whole cover-image as in. The quality of the resulting stegoimage, the secret message capacity and the security level of the proposed method are calculated and compared to other methods. Experimental results show that the proposed method outperforms the JPEG and Quantization Table Modification (JQTM) method and the Li and Wang´s work in image quality, embedding capacity and security level.