>
>>After you "sign" it, you "lock" it with a password.
>
>If there's enough information in the file to display it on the screen
>(and of course, there is) then it's possible to run the pdf through
>another app to "unsecure" it and scrub the password off. I do this
>quite often to manufacturer's secured data sheets so that I can add
>notes and highlights to my personal copies.
Aye, but then the alteration shows.