Reversible data hiding technique using histogram shifting

Reversible data hiding, in which the stego-media can be reversed to the original cover media exactly, has attracted increasing interests from the data hiding community. Recently, reversible data hiding (RDH) in encrypted images has gained attention form researchers, since it losslessly recovers original image from stego image after extraction of embedded data while it also protects confidentiality of image's content (Sreekuttyetal, 2014). Kyung etal in their paper “Histogram based reversible data hiding technique using subsampling” discussed that reversible data hiding technique guarantees that the original cover image is completely recovered from the marked image after the hidden data are extracted. Medical imaging and law enforcement are some of the areas where this technique can be applied as distortions to original image are not acceptable in such fields. In this paper, various reversible data hiding algorithms based on histogram shifting have been discussed. In 2006, the reversible data hiding algorithm is proposed by Ni, etal (NSAS). However, recovery of embedded secret data is not possible unless knowledge of peak point and zero point of histogram are transmitted to the receiver (Samriti Sharma etal, 2003). In order to improve this shortcoming, Hwang, etal (HKC) proposed a new robust reversible data hiding scheme but it decreased the data hiding capacity. In this paper an efficient location map scheme by using only one bit is proposed, which can improve image recovery.