David B. responded at time Sat, 8 Jun 2019 18:39:07 +0100 :
> Thanks for advising, 'Viking'. :-)
alls I know is there is techniques in the conclusion of this reported work
http://www.ws.binghamton.edu/fridrich/Research/double.pdf
"Overall,  we  conclude  that  malicious  manipulation  that  will  fool
the  identification  algorithm  is,  indeed,  possible  if  the  attacker
possesses  enough  skill  in  signal  processing.  We  note  that  it  is
unlikely  that  there  exists  a  numerical  identification  characteristic
computed  from  digital  images  that  could  not  be  compromised  by  a
sufficiently  sophisticated  opponent.  All  previously  proposed
techniques  based  on  defective  pixels  [3]  [6] or image features [4],
are certainly vulnerable to malicious attacks as well. Since     the
identification     technique     requires     proper     synchronization,
geometrical  operations,  such  as  cropping,  resizing,  rotation,
digital  zoom,  cause  desynchronization  and  prevent   correct   camera
identification. an  informed  attacker  can  suppress  the  pattern  noise
by  dark  frame  subtraction  and  flat-fielding.  However,  images  are
not  typically  stored  in  raw  formats  and  are  only  available   as
TIFF/JPEG,   which   means   they   are   already   processed  in  the
camera  (Eq.  (2)  in  Section  II).  As  a  result,  it  is  in  general
not  possible  to  perform  flat  fielding  correctly  from a TIFF/JPEG
image. A simpler way to remove the pattern noise PC, well-known to
researchers  working  in  robust  watermarking,  is  as  follows.  The
attacker can arrange for ñC = 0 for any image p taken with C by solving the
equation corr(p+áPC, PC) = 0 with respect to á and taking p+áPC as the
forged image. An uninformed attacker could attempt to remove the pattern
noise   by   applying   the   same   denoising   filter.   While   this,
indeed, decreases the correlation value with the correct pattern
approximately  by  a  factor  of  two,  in  most  cases  correct
identification   will   still   be   possible.   However,   repetitive
application  of  the  filter  or  more  aggressive  denoising  filters
will likely prevent correct identification. The   easiest   way   to
prevent   a   simple   detection   of   the   reference pattern is
desynchronization, such as slight rotation, possibly  combined  with  other
processing  that  might  include  resizing,  cropping,  and  filtering.
Probably  the  simplest  activemeasure  that  the  photographer  can  use
to  complicate  image  identification later is to take images using a
continuous digital zoom,  a  feature  that  many  consumer  digital
cameras  have  today."
do you know of winsoze tools specific to clean up digital fingerprints?