What is a proper or, if possible to tell, the best way to store configuration in matters of security?

So far I can tell that a database with very restricted access is a good way, but please let's exclude the database for the moment. I'm talking about things like encrypted properties files. As this is already a suggestion, I would also like to know about something like common mistakes or things I definitely have to keep in mind to acquire a secure configuration. There are already related discussions on "the best way to store configuration", however I wasn't able to find something with focus on security.

The application runs non-distributed on a host-machine, so the configuration is stored on local system. The application is, so to say, a single user application. We are talking about something like a software-firewall to be concrete. I'm actually thinking of application-scoped settings. I need data protection in a sense of privacy (I don't want to expose functionality and configuration) and integrity. I'm not afraid of an insider (admin) but more of intruders.

I already asked this question on stackoverflow but I think it is more appropriate to ask it here. I will delete the stackoverflow post in timely manner.

Disclosing the MAC address in itself shouldn't be a problem. MAC addresses are already quite predictable, easily sniffable, and any form of authentication dependent on them is inherently weak and shouldn't be relied upon.

MAC addresses are almost always only used "internally" (between you and your immediate gateway). They really don't make it to the outside world and thus cannot be used to connect back to you, locate you, or otherwise cause you any direct harm.

The disclosure can be linked to your real identity since it might be possible to track you using data collected from WiFi networks, or it can be used to falsify a device's MAC address to gain access to some service (mostly some networks) on which your MAC address is white-listed.

Personally, I wouldn't really worry about it. However, when it's not inconvenient, I usually try to redact any irrelevant information when asking for help or sharing anything.
