I want to store data that will be read from and written to by two executable files. This data file will be used to store settings that are common to both executables. To keep the user from inadvertantly modifying the data file, I would like to limit its write access. Ideally, the write access would be limited to the two executables. Also, it would be nice to have the data file be unreadable, encrypted, or un-openable to keep the user from viewing the data file. Is all of this possible? If so, which file type should I use to store the data?