An efficient technique for reversible data hiding using bidirectional histogram shifting and multistage embedding

Reversible Data Hiding has been extensively investigated due to its myriad applications in different fields such as defense, medical, cloud storage, and secure data communication over public networks. However, most of the techniques suffer due to concerns about data capacity, communication overhead, and data security. To solve these concerns, a novel technique has been proposed that ensures high security and optimum capacity, wherein no additional overhead is required to be transmitted through a separate channel. For this, bidirectional embedding of secret data has been proposed wherein both the left and right peaks from the main histogram peak have been exploited for data embedding, thereby achieving high embedding capacity. Data embedding is performed in multistage in both plain and encrypted domains to achieve not only optimum quality but also high security. The secret data embedding capacity is also tunable, wherein the number of bits per pixel can be determined from the size of the cover and the amount of secret data. In addition, block-wise embedding of secret data further enhances the data embedding capacity. The proposed technique is demonstrated to perform better in comparison to the state-of-the-art techniques while, experimental analysis over different types of cover by different performance metrics was done. On average, the PSNR (Peak Signal-to-Noise Ratio) and SSIM (Structural Similarity Index) values of 43.22 dB and 0.9984 respectively, is obtained for one bit per peak pixel embedding.