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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:50 ADT
Marcus Watts (mdw@abs0.ifs.umich.edu)
Sat, 04 Apr 1998 06:28:40 -0500
Bill Stewart wrote:
> As far as techniques for hiding data in PDF files,
> the fact that it's PostScript offers some possibilities -
> PostScript is a language for making black marks on paper,
> and you can shuffle around the order in which you make them,
> or play with the spacing between them (e.g. word spacing),
> or tweak bounding boxes by a few pixels, as well as
> shuffling words around. If your customer knows which
> techniques you're using, sometimes he can shuffle some
> of them around himself, so you need to put enough in
> that it's hard to obscure all the watermarks.
If all you care about is the postscript & pdf, and not the
resulting graphical representation (or if you just want
to do even more stuff), there's more you could do. Local variable
names, macros, and so forth are all names that are completely
arbitrary so far as the final output is concerned, so there's no
reason why they couldn't be changed to any other arbitrary string
(so long as it's still a legal variable name and doesn't conflict
with anything else.)
-Marcus Watts
UM ITD PD&D Umich Systems Group
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:50 ADT