The need to protect sensitive information privacy duringinformation exchange over the internet/intranet has led towider adoption of cryptography and steganography. The cryptography approaches convert the information into an unreadable format however draws the attention of cryptanalyst owing to the uncommon random nature flow of the bytes when viewing the flowing structured bytes on a computer. While steganography, in contrast, conceals the very existence of covert communication using digital media. Although any digital media (text, image, video, audio) can covey the sensitive information, the media with higher redundant bits are more favorable for embedding the sensitive information without distorting the media. Digital images are majorly used in conveying sensitive information compared to others owing to their higher rate of tolerating distortions, highly available, smaller sizes with high redundant bits. However, the need for maximizing the redundancy bits for the optimum embedding of secret information has been a paramount issue due to the imperceptibility prerequisite which deteriorates with an increase in payload thus, resulting in a tradeoff. This has limited steganography to only applications with lower payload requirements, thus limiting the adoption for wider deployment. This paper critically analyzes the current steganographic techniques, recent trends, and challenges.

翻译：在互联网/内网信息交换过程中保护敏感信息隐私的需求推动了密码学与隐写术的广泛应用。密码学方法将信息转换为不可读格式，但由于计算机上结构化字节流呈现异常随机的特征，容易引起密码分析者的注意。相比之下，隐写术利用数字媒体隐匿隐蔽通信的存在。尽管任何数字媒体（文本、图像、视频、音频）均可承载敏感信息，但冗余位较高的媒体更利于在不扭曲媒体的前提下嵌入敏感信息。相较于其他媒体，数字图像因其对失真的容忍度更高、易获取性更强、体积小巧且包含高冗余位等优势，成为传输敏感信息的主要载体。然而，由于不可感知性要求会随有效载荷增加而劣化，导致性能权衡问题，如何最大化冗余位以实现秘密信息的最优嵌入一直是关键难题。这一局限性使得隐写术仅适用于低有效载荷需求的应用场景，从而制约了其大规模部署。本文对当前隐写技术、研究趋势及挑战进行了批判性分析。