“…Many RDH algorithms have been developed in various methods and applications, which are analyzed from different aspects, like in encrypted images [5], digital audio-based classification [6], trends of digital image-based data hiding [7], attack to cipher images [8], two-layer embedding [9], and predictor-based RDH [10]. In detail, the introduced methods include difference expansion (DE), histogram shifting (HS), and pixel value ordering (PVO), for various purposes, like file tampering detection [11] and watermarking [12]. Furthermore, RDH can be developed in various media, like image [7], audio [6], and video [13], with either spatial or frequency domain.…”