A Weighted Location Based LSB Image Steganography Technique

Steganography is the art of hiding the presence of communication by embedding secret messages into innocent, innocuous looking cover documents, such as digital images, videos, sound files. We present here a novel steganographic method based on affine cipher encryption algorithm and the least significant bit (LSB) substitution in order to provide a strong security and imperceptible visual quality to secret message. We encrypt the 8 bit secret image by changing pixel values using affine cipher. After that each 8 bit pixel of encrypted secret image is divided into 4 groups of 2 bit each. Each part which have a decimal value between 0 to 3 determines the location in each pixel of cover image where to embed the message. We do not store the actual secret message instead we encode the secret message into cover image using the value of each group of secret message. Since, we have two layers of encoding: one using private keys of affine cipher and other for steganography, our methods proves to be more secure than others. Our experimental results also proves that the proposed method has got an acceptable image quality as supported by PSNR values.