Reversible data hiding in encrypted images with public key cryptography: a review of its benefits and open issues

Reversible data hiding is a new research direction of data hiding technology. In particular with the adoption of cloud services, reversible data hiding in encrypted images is a well-known notion of achieving privacy protection in the cloud environment. According to the encryption method, it can be classified into symmetric encryption and asymmetric encryption. Compared with symmetric encryption, asymmetric encryption system allows homomorphic addition and homomorphic multiplication to be performed in the ciphertext domain, which makes the information hiding process more secure and the content is more effectively protected. However, there are some problems in existing schemes. The aim of this paper is to analysis recent issues regarding reversible data hiding in encrypted images with public key cryptography, and offer valuable solutions to the aforementioned issues, including feasible theoretical basis. Finally, focused on the technology needs and difficulties, several future directions in this field are proposed.