Data Hiding and Integrity Verification based on Quotient Value Differencing and Merkle Tree

The three important quality aspects of image steganography mechanisms are hiding capacity (HC), peak signal-to-noise ratio (PSNR), and attack resistance. While the stego-image (SI) is on transit from sender to receiver, the camouflaged data may be altered due to several reasons. No existing steganography technique focuses on evaluating the integrity of extracted data at the receiver. Therefore, there is a need to develop techniques to check the integrity of the extracted bits from the SI at the receiver. This article offers a steganography technique with integrity check at the receiver. The image is sliced into various non-overlapping blocks of size 3 x 3. The secret information is camouflaged using bit replacement and differencing mechanisms in 7 MSBs of the 9 pixels. After bits are camouflaged in these 7 MSBs of all the pixels, the verification bits are generated using Merkle tree concept. The root of the tree holds the verification bits and these are camouflaged in the LSBs of various pixels in the block. The experimental outcomes report that without compromising the HC and PSNR values, the extracted data at the receiver could be verified successfully.