Please see if you can help me out on this.
I have a CD that contains files (doc, xls, htm etc.) pre-encrypted with a program written by me. If someone simply inserts the CD and reads the files in Word, Excel or IE, he gets encrypted garbage.
I want the user to always access the proper content of the CD after running a startup EXE, which is also written by me. The startup program, when run by the user, resides in memory (may be in system tray as well). Once this program is loaded, it intercepts any i/o on the CD made from Word, Excel, IE or other apps, and decrypts the content on-the-fly and returns readable content to that app.
I have not yet written any of these programs! :-) I am planning to.
My question is - how to accomplish this? The encryption and decryption part can of course be taken care of by me. I am concerned about intercepting any i/o calls to the CD. Please remember, I do not know which applications will access the CD files. So, I need to trap system-wide i/o calls to the CD and return proper output.
How to do that?