Link chain driven reversible data hiding in encrypted images for high payload

In the last decade, data hiding in encrypted image has got a lot of attention within the security and privacy researcher’s communities. This attention has led to the development of various reversible data hiding techniques for encrypted images (RDHEI) which enables separable lossless recovery of cover media and extraction of the secret message, at the receiving end. In this paper, a link chain driven (LCD) RDHEI algorithm for providing high embedding capacity, is proposed. The LCD-RDHEI exploits neighbourhood similarity of image pixels and clubs them in variable size link chains. The pixels in each link chain are estimated either by their average or using two quantization values based on the size of link chains. This helps in reserving a big room inside the image which can be used to fill in the secret information. Additionally, the pixels which are not part of any of the link chains are also utilized for embedding the secret information by adaptive multi MSB prediction and Huffman Coding method. Experimental results show that the LCD-RDHEI provides significantly greater embedding capacity than the existing and related modern data hiding method for encrypted images.