Is it possible to store passwords on the local system (Windows XP) that can only be accessed by the application itself?
My instinctive answer would be "no". Even if some kind of hashing or encyption is used I would think that as long as the source code is available then the determined seeker could always use this to retrieve the password.
I'm working on a personal open source hobby project in which I would like to give users the option of storing passwords on disk so that they don't need to type them every time they use the software. One example of a password that could be stored would be the one used to authenticate on their network's proxy server.
There are a few related questions here on Stack Overflow and the most appropriate solution sounds like using an operating system service like DPAPI.
Is the basic premise correct that as long as the password is retrievable by the software without any user input, and the source code is open source, that the password will always be retrievable by a (suitably technically and willfully inclined) passer-by?