Making documents attached password protected
In my application, there is a facility in which a user uploads documents and also view the same uploaded different documents and sometimes view those that were uploaded by admin user.
How can i make these different documents password protected?? Will this protection (coding) differ from filetype to filetype (Allowed file types are : gif|jpg|png|pdf|txt|doc|docx|xls|ppt|jpeg|tif|tiff )
I dont know how to go abt this.
Can some one guide some link or help on this
Thanks in anticipation