Reversible Watermarking based on Histogram Shifting Modification:A Review

When we talk about the data communication or exchange of information from sender to receiver, the major concern is DATA. This (data) being of high importance, prone to various kinds of attacks. In order to protect it, data hiding techniques are used. Some of the data hiding techniques available are digital watermarking, steganography, etc. By digital watermarking, data is hidden in any type of multimedia like images, audio, etc. Watermarking is one of the major solution to provide authenticity and copyright protection to the digital data. But watermarking causes damage to the cover signal (signal in which data are embedding), therefore recovery of the original cover signal is not possible at the receiving end, which is not tolerable in many fields like medical, military, etc. To reduce the degradation in the watermarked signal "Reversible watermarking techniques" are used. In reversible watermarking original cover signal and the message are retrieved with fewer errors. Reversible data hiding techniques are also known as the Lossless data hiding techniques. This technique is getting high importance day by day because of some fields like military, medical, etc. This paper describes the various reversible watermarking techniques which are already existing. Index Terms: Reversible watermarking, Histogram shifting, Authentication.