i have created a file association by creating my own file extension. i have registered the new file extension to a particular application. i then opened notepad and put in a few sentences i and saved the file with my new file extension. when i click the file my program opens which is what i want to happen. however if i go through notepad or word and click open files and click the filename with the new extension the file opens and is readable, why is that?

i want it to be unreadable in other applications just like pdf files can't be read in word or notepad is what i want for my file extension. is this possible?

another problem is, my program is a login application, so the user has to log in to see and read the file, however when the user enters the correct info the file does not show. is there something i'm missing? am i required to write code in my program too? if so what?