Glad I came across this post. I think I can expound on the solution as I am looking for some help in the area. You can create a table of users and passwords with the passwords being MD5 hashed. This way, instead of checking a harcoded constant within the programming, you can check against an encrypted variable that if a user were to try to find would still be unable to break it easily.
If you are looking for something way more secure, than this is probably not it, but this does deal with not allowing everyday average users to see reports that they need not be seeing.
So the question is, what is the next step? I have created tblUsers with fields userName and pWord. I am only sure in theory how to check the user and password and not sure what it looks like in code. Also, can the tblUsers itself be protected against editing? I wouldn't want someone to get in there and delete the hashed password, thus making the report inaccessible to everyone.