A new colour image steganography using LSB approach with halftoning determination embedding position

Abstract

Steganography is the art and science of encoding secret messages in such a way that no one, apart from the sender and intended recipi- ent, suspects the existence of the hidden message. The Least Significant Bit (LSB) insertion is a well-established method for embedding the secret message that is known for its superiority in terms of imperceptibility; however, it suffers from robustness against Chi-square attack. In this study, a new colour image steganography technique is proposed using the LSB insertion coupled with a halftone image, which is used to determine embed- ding pixels. The technique involves four stages: secret message preparation, image halftoning, embedding and extraction. Firstly, the secret message is converted from character to a bit-stream. Secondly, a halftone image is created from the cover image in order to determine the embedding pixels. Thirdly, the secret message’s bit-steam is sequentially embedded onto the embedding pixels until all the bits are exhausted. Upon the embedding, final stage is to extract the embedded secret message; this is done in the same way as embedding process except it is performed in a reverse order. A series of experiments is conducted using a standard dataset to evaluate the performance of the proposed method in terms of both imperceptibility and robustness.