Reversible data hiding

Reversible data hiding, in which the stago-media can be reversed to the original cover media exactly, has attracted increasing interests from the data hiding community. In this study, the existing reversible data hiding algorithms, including some newest schemes, have been classified into three categories: 1) Those developed for fragile authentication; 2) Those developed for achieving high data embedding capacity; 3) Those developed for send-fragile authentication. In each category, some prominent representatives are selected. The principles, merits, drawbacks and applications of these algorithms are analyzed and addressed.