A survey of reversible data hiding in encrypted images – The first 12 years

International audience; In the last few years, with the increasing popularity of cloud computing and the availability of mobile smart devices as well as ubiquitous network connections, more and more users are uploading their personal data to remote servers. However, this can lead to significant security breaches, where confidentiality, integrity and authentication are constantly threatened. To overcome these multiple problems, multimedia data must be secured, for example by means of encryption before transmission and storage. In this survey, we look into the issues involved in handling encrypted multimedia data, and more specifically we focus on reversible data hiding in encrypted images (RDHEI). The aim of this survey is to present the birth and evolution of RDHEI methods over the last 12 years. We first highlight different classes and characteristics of RDHEI, then describe representative RDHEI methods. A comparison table is presented to summarize the key features and achievements of each representative RDHEI method considered in this survey. Finally, we share the future outlook of emerging applications and open research topics relevant to RDHEI for the next 12 years and beyond.