Does your multi-user application require a log into the database or is it set so that anyone that has the program can run it?

Most of my applications have a access file where each individual's userid and password are encrypted. When the application is started, they have to put in their userid and password which is encrypted and seeked on the access table. No found, kill the program. They may be able to steal the program but not run it unless someone sets the up in it. Encryption is used so that someone cannot use another applcation to just add themselves to the access table.