AccessPermission can be used without encrypting the PDF. That's why I said it is not related to encryption.
However, if you are encrypting something, AccessPermission will be used. So I'd still say that AccessPermission is not related to encryption. If you had to encrypt the file in order to use AccessPermission, then I would agree that it is related to encryption. On Thu, Aug 25, 2011 at 6:02 PM, Ken Bowen <[email protected]> wrote: > Hello Adam, > > Thanks for the reply. Unfortunately, we're not interested in encrypting the > form; only in preventing > further changes beyond a nominal "finished" point. I was only hoping for a > "global" way of doing that. > > I think you may have made an error when you said > >> Now, to answer your question, the AccessPermission class is not related >> to encryption, > > Since org.apache.pdfbox.pdmodel.encryption.AccessPermission is part of the > encryption package, > and since it also used as a argument to the StandardProtectionPolicy and > PublicKeyRecipient > constructors, it is clearly "related" to encryption. > > Regards, > Ken > > On Aug 25, 2011, at 12:21 AM, Adam Nichols wrote: > >> Hello. >> >> First, let me explain what the options are in terms of protecting a PDF. >> There are three different types: >> 1. No protection. There's no encryption, no passwords, and anyone with >> the right software can read, modify, extract, print and whatever else >> they desire. >> 2. PDFs with an owner password. These can be opened and read by anyone, >> however there are some flags which are set which say "please don't edit >> this", "please don't print", and so forth. From a technical standpoint, >> there's nothing stopping anyone from doing these prohibited actions, but >> most software will respect these flags and only allow you to preform >> prohibited actions if you enter the correct owner password. >> 3. Then there are PDFs with a user password. These can not be opened, >> read, or processed in any way without the user password. There is >> encryption (RC4 or AES) which stops anyone from bypassing this, no >> matter what software they use. Once the correct password is entered, >> the file is decrypted and it treated like #1 or #2. >> >> Now, to answer your question, the AccessPermission class is not related >> to encryption, however it is related to the owner password. You will >> not need to enter a password to open protected files (as long as there's >> no user password); you will only need the password to edit them. Just >> keep in mind that it's only going to stop people who didn't REALLY want >> to edit it. >> >> There's no way to use strong encryption to enforce the editability of >> the file. As long as the program can process the file enough to know >> what to render, then it has everything it needs to write out a copy and >> modify the copy. >> >> Hope this helps you understand how PDFs work, and how the class works. >> >> --Adam >> >> On 08/24/2011 08:19 PM, Ken Bowen wrote: >>> Hi Everyone, >>> >>> We have routines which create and fill out pdf forms using PDFBox. >>> After creating and filling the fields, we need to make all of them >>> read-only. >>> Is there a global way to do this with PDFBox for a form? >>> Or do I need to go through and apply PDField.setReadonly(true) to each >>> field? >>> >>> I've observed that org.apache.pdfbox.pdmodel.encryption.AccessPermission >>> has a bit for setting fields read-only, but it seems this class is only >>> related to encyrpted PDFs -- is this true? >>> >>> Thanks in advance, >>> -- Ken >>> > >
