Reversible data hiding in encrypted images without additional information transmission

Reversible data hiding in encrypted images (RDHEI) is an essential branch of image reversible data hiding. Over the past decade, many significant achievements have been made. However, for most RDHEI researches, the cloud service user (CSU) demands either an encryption method specified by the cloud service provider (CSP) or prior knowledge about the original image to indicate the preprocessing operation. This characteristic may lead to some security issues like information leakage that may limit the use of this type of technology. To solve this problem, we propose a simple but effective RDHEI method that separates the CSU and CSP. The owner CSU exclusively sends the standard stream cipher image to the CSP, while the CSP can embed message data into the encrypted image through a simple MSB replacement without knowing the encrypted method or prior knowledge about the original image. The embedded message data can be extracted; meanwhile, the image can be approximately recovered by another authentic CSU. Since the proposed fundamental method is not error-free in most circumstances, we provide an alternative option to achieve reversibility by transmitting a perfect recovery key from the owner CSU to any authentic CSU. The experimental results demonstrate the efficacy of the proposed method.