Secret data modification based image steganography technique using genetic algorithm having a flexible chromosome structure

Abstract

In all forms of confidential communication, the most significant element is security. Cryptography can be used to secure the information, but it discloses the presence of covert communication. Hence, steganography was invented; steganography is an art of concealed communication. Steganography is performed by inserting the secret information in a cover media to camouflage the presence of covert communication. In image steganography, an image is used as the cover media for secure communication. There are various image steganography techniques invented by many researchers, but a small number of them focus on improving visual quality and increasing payload capacity simultaneously. This paper presents a secret data modification based high capacity image steganography technique using genetic algorithm (GA). This new technique uses the least significant bit (LSB) replacement steganography, to embed the secret data. However, the secret data is rearranged and modified before embedding it in the LSBs of the cover image. The parameters used to rearrange and modify the secret data are controlled by GA. A unique concept called flexible chromosome is introduced which allows GA to interpret the chromosome value in different ways. GA attempts to find the best possible parameter value that yields high visual quality of the stego images. The stego images produced by the proposed technique have an average PSNR value of 46.41 dB and 40.83 dB for 2 bit per pixel (bpp) and 3 bpp data hiding capacity respectively.