The image is significantly used in applications such as medical area, research area, image conferencing, a military image system, online transactions, digital signatures, passwords etc. But not everyone who uses this network is going to play by the rules or have the best interest at heart. Just as we have physical security like locks, fences and police officers to minimize crime in the real world. We need some security to minimize crime and harm in the virtual world. Three important factors form the security objectives of the digital content: they are Availability, Confidentiality, and Integrity. Watermarking techniques along with some Cryptography are used to protect the confidentiality of data. Watermarking is basically a process of injecting data into an image in such a way that it can depict the authenticity of those possessing it. The digital information hidden inside an image is imperceptible to the user but can be easily detected by a computer or various digital devices. Watermarking Technique has proved to be a powerful technique for image security and a lot of research has been made over the years to how to embed the watermarks and recover the watermarks effectively. These types of technique where watermark can be fully extracted from the image and along with the restoration of the cover are popularly known as Reversible Watermarking techniques. These techniques have significantly gained importance due to this excellent recovering property making them suitable for content authentication based applications. However, they are not able to identify any modifications or changes done in watermark making it susceptible to tamper location-based attacks. Due to the rapid development of watermarking techniques, a concluding review of recent research in this field is highly desirable. However, the major focus of this paper is on tamper localization based reversible watermarking techniques.
Reversible Fragile Watermarking Scheme for Relational Database Based on Prediction-Error Expansion
