Very High Capacity Image Steganography Technique Using Quotient Value Differencing and LSB Substitution

This article proposes a very high capacity steganography technique using differencing and substitution mechanisms. It divides the image into non-overlapped 3x3 pixel blocks. For every pixel of a block, least significant bit (LSB) substitution is applied on two LSBs and quotient value differencing (QVD) is applied on the remaining six bits. Thus, there are two levels of embedding: (i) LSB substitution at lower bit planes and (ii) QVD at higher bit planes. If a block after embedding in this fashion suffers with fall off boundary problem, then that block is undone from the above hybrid embedding and modified 4-bit LSB substitution is applied. Experimentally, it is evidenced that the hiding capacity is improved to a greater extent. It is also experimentally proved that pixel difference histogram and RS analysis techniques cannot detect the proposed steganography technique.