Comprising Survey of Steganography & Cryptography: Evaluations, Techniques and Trends in Future Research

At the moment, multimedia data protection has become a critical activity. It is primarily utilized when information confidentiality is vital, which can be accomplished through cryptography and Steganography. These methods conceal not only the message itself but also its existence. These techniques have a variety of services in various sectors, including defense, medicine, and online transactions. Both approaches must have an ample key space resistant to brute force searches, low execution time complexity/high speed, and the ability to generate substantial confusion and diffusion for adequate security. Various encryption and steganography techniques have been employed to safeguard confidential digital data from those attempting to gain access illegally. This research paper includes an in-depth analysis of existing types of cryptography and steganography techniques and recent advances to both categories in numerous modalities, most notably image and audio data. The research highlights the security improved by applying various cryptography and Steganography techniques. Also, a brief classification of the multiple methods used in both approaches is done. In the case of cryptography, this classification is based on classic and modern techniques. Apart from cryptography, various existing steganography techniques are classified based on retrieval, embedding domain, adaptive nature, and theory or a key idea.