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openoffice.org package

export pdf safety does not work

Asked by Utz

I try to export a document as pdf and would like to prevent changes and printing. Under Settings I do set a password and mark the appropiate checkboxes, but any time I end up with a changable and printable pdf. The only restriction that seams to work is the open document password. My version is ooo-build 3.2.1.4. Any hint? Thanks

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mycae
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Best mycae (mycae) said : 		#1

Non-printable documents are not real. They merely set a "please don't allow me to be printed software" flag. Most open-source software will simply ignore this flag, as the ethos is that the user is in charge -- the user can choose what to do with their own data.

http://lwn.net/Articles/335415/

Encryption however is real. Encrypted information (assuming the encryption algorithm is good) cannot be recovered, due to the use of something known as a "trapdoor function" - a one-way mathematical function which can mix several values together trivally to generate a final value, but it is much harder to reverse the process.

As an aside, the WWF recently tried to make a file "format" that was simply PDF with this flag set, and were pretty-much booed off the stage:
http://thebeezspeaks.blogspot.com/2010/12/world-wildlife-fund-wwf-format-cracked.html

Here is a snippet from that page (its a translation from the German):
"That's what it's all about. Of course you can specify that a PDF cannot to be printed. However, many people are not familiar with this feature. But those who are not computer savvy should be made aware of their choices."

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Utz (utz-recke) said : 		#2

So the flags are more like a hint and depend on the sw used.
 In my case it was about a contract proposal. Finally I opted to use a watermark to make it somethat harder for non computer savvy to have it appear like a real contract.

Thank you for your answer, the acticles are intresting points of views.