IMPROVED STEGANALYSIS OF LSB EMBEDDED COLOR IMAGES BASED ON STEGO-SENSITIVE THRESHOLD CLOSE COLOR PAIR SIGNATURE

摘要

This paper proposes a method for the detection of the Least Significant Bit (LSB) steganography using images as cover objects. Steganography methods attempt to insert data in multimedia signals in an undetectable manner. But these methods distort the underlying signal characteristics, thus allowing detection under careful steganalysis. When embedding is carried out repeatedly, distortion in signal characteristics is highest during the first embedding and decreases subsequently. This principle is used to detect the presence of hidden messages in 24 bit bmp images. This paper proposes improvement to close color pair analysis with stego-sensitive threshold to detect stego objects. Stego-sensitive threshold is calculated based on the structural similarity index measure of the samples. This threshold can be further varied in a range to improve the detection rate. Experimental results indicate thar this approach is able to distinguish clean and stego images with promising accuracy.