  The synchrotron hump of the high energy peaked blazars generally lies in the
0.1-10 keV range and such sources show extreme flux and spectral variability in
X-ray bands. Various spectral studies showed that the X-ray spectra of high
energy peaked blazars are curved and better described by the log-parabolic
model. The curvature is attributed to the energy dependent statistical
acceleration mechanism. In this work, we review the X-ray spectral studies of
high energy peaked blazars. It is found that the log-parabolic model well
describes the spectra in a wide energy interval around the peak. The
log-parabolic model provides the possibility of investigating the correlation
between the spectral parameters derived from it. Therefore, we compiled the
studies of correlations between the various parameters derived from the
log-parabolic model and their implications to describe the variability
mechanism of blazars.
