Encrypted Image based Reversible Data hiding using Invertible Image Conversion

In recent years, with the growing recognition of cloud computing, data outsourcing has become a widely used service. Also, to preserve privacy and security of sensitive data, it is important to encrypt the data before outsourcing it to the cloud. Due to such requirements, reversible data hiding in encrypted image (RDH-EI) has received significant interest from the researchers. In this paper, a new technique for RDH- EI is suggested based on invertible image conversion unlike the conventional RDH-EI techniques. In this method, instead of generating and storing the encrypted image in unintelligible form (cipher formed image) which may easily attract the attention of intruders or hackers, it allows the user to convert the semantical content of original image into the semantical content of a freely selected target image of the same size. Image block mapping is performed between original and target images using mean absolute deviation and a compression technique is applied for reducing the information of image block position by grouping the blocks into two uneven proportion i.e. 0 or 1 based on the sorted mean absolute deviation value for both original and target image blocks respectively. Comparison with the existing techniques shows that the proposed method yields better results.