Histogram shifting (HS) based scheme was initially presented by Ni et al. [17]. It selects a pair of peak bin (with highest frequency) and zero bin (with zero frequency) in histogram as side information and then shifts those bins between peak and zero bins by 1 towards zero bin to create vacant space nearby the peak bin. Finally, each pixel at peak bin is employed to embed 1-bit secret message for reversible data hiding. The process is simply illustrated by Fig.1(a) and the result is shown in Fig.1(b). It is also can be simply represented by Fig.2 by ignoring the vertical axis, where each value in the parenthesis means the frequency of one bin in current histogram.