Improved least significant bit algorithm based on RS-code

Abstract

As a widely applied data hiding method, least significant bit (LSB) algorithm is a spatial steganography which uses the lowest bits of each pixel’s grayscale value to hide messages. In spite of its high capacitance, high load rate and imperceptibility is remarkable, the lack of robustness is the fatal problem which prevents the LSB algorithm’s further application. This paper proposes a new high-robustness LSB method based on the Reed-Solomon (RS) code and provides higher immunity of attack with slight cost of imperceptibility and capacity. This algorithm exploits the considerable error correction ability of RS-code to encode the watermark message before embedding them to the carrier image. Despite the size of the encoded message increases times to the original, this method makes self-correction of encrypted images feasible, which would provide more superiority among the algorithms that require carrier image as reference to extract watermark message. This paper provides the testing results of the LSB algorithm based on RS-code in Matlab and verifies the immunity of both the proposed method and original method against noise and rotation attack, and finally determines that this algorithm is able to substantially enhance the robustness of encrypted image under a certain range of noise density.