You probably want a 7th level hacker for that, then.
I've never hacked a raw pdf, but I know it's text, which means that someone who is good with perl and knows what to look for in the pdf should have no trouble at all
Unless there is some stupid cryptographic checksum involved.
If there is, there should be a way to turn it off, however.
Come to think of it, there might even be a utility out there to do something very much like that.