Overview of methods to improve execution time in image steganography and watermarking

The cybersecurity problems remain extremely relevant in the modern world. Every year image steganography and watermarking schemes are proposed that solve the problems of hidden confidential data transfer and image authentication, respectively. The authors attempt to maximize the main embedding indicators, such as capacity, invisibility, and robustness. However, in practice, the time effectiveness of embedding schemes also becomes paramount. Some schemes can provide outstanding embedding quality according to the main embedding indicators but have unsuitable time complexity for real-world applications. Others, on the contrary, aim to satisfy the requirements of real applications, sacrificing the main indicators in the process. Some authors manage to achieve the trade-off between embedding efficiency and algorithm complexity using special measures. Yet, in many works, these solutions are not covered in detail. In this paper, an overview of relevant studies in image steganography and watermarking, the authors of which apply various techniques for speed improvement, is presented. Algorithmic, software, and hardware approaches to improving computation time are analyzed separately, and the most widespread solutions are highlighted. The overview ends with promising research directions for improving the performance of additional information embedding into digital images in the context of execution time.