Didn't have PDF::Tk installed, therefore my first answer was wrong. Looking at the source of PDF::Tk, it seens to me it would have to be modified to fit your needs, better use 
system ('/apps/free/pdftk/1.44/bin/pdftk', 'apps.pdf', 'output', 'test
+.pdf','owner_pw','abc12345') or die ...;

[download]
(or 
system '/apps/free/pdftk/1.44/bin/pdftk apps.pdf output test.pdf owner
+_pw abc12345' or die ...

[download]
or use qx). Note the additional output in the command, PDF::Tk does insert this, too, but not where you would want it.

In reply to Re: pdftk encryption function by soonix
in thread pdftk encryption function by Anonymous Monk

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