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 recipient, suspects the existence of the hidden message. The Least Significant Bit (LSB) insertion is the well-established method for embedding the secret message that is known for its superiority in terms of imperceptibility; however, it suffers from robustness against the Chi-square attack. In this study, a new colour image steganography technique is proposed using the LSB insertion and coupled with a halftone image, which is used to determine embedding 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. The experimental results have revealed that the method yielded very high imperceptibilty with Peak Signal-to-Noise Ratio averaged at 67dB, and was able to withstand against the Chi-square attack