I am using this (PrinceXML Version 7.1 Non-commercial License):

/usr/bin/prince --server -s "css.css" --input=html --log="log.log" --encrypt --key-bits 128 --user-password="" --owner-password="" --disallow-print --disallow-modify --disallow-copy --disallow-annotate file.html -o "file.pdf"

in order to not perform the printing of the pdf final document.

It all works, except a strange behavour of all "search" button or tools in Acrobat Reader (I try it on Win and Mac both with Adobe Reader 9.1 and 10, but I think it would not work even with all other platforms and all other versions of Adobe Reader): when you search for a word like "pippo", it finds other word completely not like that, such as "topolino" or "paperino"!!!
So, you can't find what you're looking for if you don't want to permit the printing of the PDF.
Something happened like in this thread: http://www.princexml.com/bb/viewtopic.php?f=2&t=394&p=1093&hilit=encrypt#p1093

Does Anybody have a solution for this???

Il pensiero fa la grandezza dell’uomo (B.Pascal)

We have not been able to reproduce this issue ourselves yet, would you be able to post or email me (mikeday@yeslogic.com) a small PDF generated by Prince that demonstrates the problem?

Ok, I'm sending you an emal with 3 files: the html file I'm trasforming to PDF, the PDF created without encrypt options and the one with the encrypt and disallow-print option. Just a few minute and I'll send you a file using my luciorules@libero.it account. Hope you can understand and help me to resolve the problem.
With the document I'll send to you, try to search (I'm using Adobe Reader 9.1, but tested even with Adobe Reader 10) the string "preside" and note the different behaviour in the crypted troughout the not-crypted document: in one you find all the matches, in the other you'll strangely find other not corresponding word...

Il pensiero fa la grandezza dell’uomo (B.Pascal)

could it be this problem with Adobe's search function?

http://superuser.com/questions/272321/searching-a-pdf-in-adobe-acrobat-and-reader-returns-incorrect-results

We have not been able to reproduce the problem with Adobe Reader X, so it may be specific to earlier versions. The search cache issue listed above seems like a prime suspect.