Reversible Data Hiding in Encrypted Images Using POB Number System

Prediction-error expansion (PEE) methods usually involve the shifting process between peak points and zero points in order to vacate room for embedding. This occurrence will inevitably impose a troublesome because overflow/underflow issue after data embedding may occur, in turn, it dramatically increases the amount of auxiliary information to be transmitted or map information to be embedded. Besides, PEE-based reversible data hiding in encrypted images (RDHEI) methods usually adopt a block-size encryption strategy, but the correlation reservation of intra-block for subsequently embedding may leave opportunities for potential attacks. To deal with these issues, we proposed a novel RDHEI method with the functionality of embedding synchronized with re-encryption, which is well carried out by a data hider using a permutation ordered binary (POB) number system. Unlike conventional PEE-based RDHEI techniques, this scheme takes advantage of two peak points for embedding, but thoroughly abandons the former idea of shifting process. Experimental results verify the superiority of the proposed method, which not only may extend the applications of PEE-based RDHEI schemes substantially, but also vastly extend POB number application scenarios in practice.