5 - Image steganography using add-sub based QVD and side match

Abstract

Fall off boundary problem (FOBP) arises in many steganography schemes that use the concept of differencing between two pixel values. This chapter presents a new steganography scheme using add-sub based quotient value differencing (ASQVD) and side match (SM) to address the FOBP. It performs two stages of embedding on 3×3 size disjoint pixel blocks. In stage 1, it performs ASQVD and remainder substitution on the central pixel and its left, right, lower, and upper neighbor pixels. Based on new values of these five pixels, in stage 2, it performs SM embedding approach on four corner neighbors. From experimental observations it has been derived that this scheme hides relatively larger amounts of data. The principles of differencing and substitution have been used in this scheme, so pixel difference histogram (PDH) and regular-singular (RS) tests have been utilized to verify the security of this new scheme. Fortunately, these two tests fail to detect this steganography technique. The average hiding capacity is 3.55 BPB. It is greater than in the existing techniques.