Advancements in Reversible Data Hiding in Encrypted Images Using Public Key Cryptography

With the evolving needs of cloud-based information exchange, the challenge of a reliable and secure communication channel has also been the center of attention recently. Although cryptography has been a traditional tool for secure communication; yet it also carries a possibility of attacks aimed to gain access to the sensitive information. As an alternative, the use of reversible data hiding (RDH) technique has been proposed. RDH scheme involves concealment of the data in the cover image, both of which are retrieved in a lossless manner at the receiver end. Over an insecure channel in cloud communication, the cover content is encrypted; thus resulting in Reversible Data Hiding in Encrypted Images (RDHEI). RDHEI traditionally uses symmetric key cryptography involving a drawback of key management overhead. Public key cryptography (PKC) offers an alternate and efficient solution for cloud-based environments in which the homomorphic properties of public key are utilized. This paper provides an overview of the recent advancements in research in the context RDHEI based on PKC; discussing several proposed schemes addressing the core challenges of data expansion and complex computations using public key encryption. In addition to this, the shortcomings of the discussed schemes are highlighted along with possible remedies that will also guide new directions for future work.