Reversible data hiding in encrypted images based on bidirectional encoding for payload enhancing

Abstract

Reversible data hiding in encrypted images (RDHEI) has received substantial attention as a pivotal research domain in the field of secure data embedding. This paper presents a novel RDHEI approach using bidirectional flag encoding. Our method substantially enhances embedding capacity while ensuring both lossless image recovery and accurate extraction of hidden data. The original image is processed using a hybrid prediction model to derive prediction error values. Subsequently, the image undergoes encryption through a combination of a stream cipher technique and block scrambling to guarantee robust security. Finally, the bidirectional flag encoding technique is employed to vacate the room for data embedding. By leveraging spatial correlation among pixels, this scheme achieves an improved embedding rate. Experimental evaluations reveal that the proposed method achieves an enhanced payload capacity in comparison to existing state-of-the-art RDHEI techniques. The average embedding rates on datasets of BOSSbase and BOWS-2 are 3.76 bpp and 3.37 bpp, respectively.