Hi,
I have an application where a user can download a PDF for printing.
I want to be able to resrict the number of copies that can be printed.
Is it possible to digitally sign/restrict a PDF in this way?
Regards
views:
414answers:
5
+1
A:
Basically, no. That would mean that you have to write somewhere the information of how many times the PDF has been printed. All that would be required to print it more time would be to make a copy of the file before printing, and print the copy. The original would still have the information that it is not printed.
Worst case, it is always possible to print it once and make xerox copies after, so you dont gain much by being able to restrict the number of prints.
Guillaume
2008-12-11 09:33:04
This is incorrect, the number of printings can be restricted and this is commonly used, e.g. for academic paper PDF's where the person downloading will only be able to print a copy once.
Drew Gibson
2008-12-11 09:44:57
It is easy to come up with the idea of giving the PDF a unique identify (an embedded GUID, encrypted or otherwise hidden so it's hard to change, I guess), and then putting the print-counter on a remote server. So it doesn't *have* to be in the file itself.
unwind
2008-12-11 09:56:55
A:
Why impose arbitrary limitations on something you can easily copy as much as you like with other means?
Your customers won't be happy.
Nailer
2008-12-11 09:43:31
For some content, it against the law to make a xerox copy. This doesn't stop you doing it of course. When you are in that situation it's up to you whether you don't mind getting fired if you get caught.
Drew Gibson
2008-12-11 09:49:07
A:
I want to be able to resrict the number of copies that can be printed.
The legal solution of copyright law is probably more appropriate than a technological one which may be questionable and/or annoying to customers.
IEEE has a solution they use for their technical library documents, namely they are now merging the original document with a footer saying "Permission to use this document granted to _@____.com" before serving it to everyone -- it doesn't stop someone from printing out the file or copying the file, but it does put the reader's name on the document so that if someone does print out 50,000 copies it will have their name on it & hence make legal enforcement of copyright law a little easier.
Jason S
2008-12-11 15:16:18