You can get PDF file detail, such as subject, title, security setting some other information ser by document creator. How you can do this lets learn here.
Just open PDF file in adobe reader 9 or adobe acrobat pro.
Click on File in menu and then go to Document properties and Summary, you can also select document summary from document pane menu.
Now you can reader basic information about PDF file like, Subject, title, author and keywords if have been set by file creator.
You can also change file security and other information by yourself from this window using Adobe Acrobat Pro.