Prabhash Kumar Singh
The internet has made distances shorter and the world smaller for communication. As per the survey done by Internet World Stats in June 2019, 58.8% (i.e. approximately 4.5 billion) of the total world population are using the internet. World Economic Forum report of 2018 suggests that by 2030, nine out of ten persons above fifteen would be online and digital conscious. Nowadays, the internet has become essential for living and running businesses smoothly. The latest web-enabled devices and high-speed communication technology have revolutionised the sharing of multimedia documents. It can be for various purposes, including social, commercial and industrial applications. Therefore, the first requirement is to protect the digital content from unauthorised access. As a result of rising cyber-terrorism and the widespread availability of the internet, data integrity is jeopardised. It can cause financial and emotional damage by stealing data or manipulating it. Thus, it is necessary to provide comprehensive security solutions with continual updates to counter fraud and evil intents. Effective prevention of forgery of digital works and identification of intellectual property rights of digital media have become an urgent problem which needs to be solved. A possible solution leads to data hiding technologies which embed valuable secret data within the multimedia objects such as image, audio or video to protect from adversaries. Data hiding can be achieved through cryptography, steganography and watermarking techniques. Each has its own advantages and disadvantages. Over the years, various data hiding techniques developed can be classified as reversible or irreversible. In reversible techniques, original host file, referred as cover, can be recovered after extraction of the secret message from the media in which the secret data was hidden (stego). Medical and military fields where the original image is as vital as the secret message prefers reversible techniques. Any changes to the original cover during transmission can affect the recoverability of the secret message. An irreversible data hiding algorithms enables the recovery of the hidden secret data however, fails to recover the original cover image.
