Windows (in this case XP) allows me to simply "share a folder" via its SMB protocol, and I can access it via Linux quite nicely (with Samba), no questions asked.
That's what bothers me, it just does not feel secure, and the "security" section of the Wikipedia page is discouraging. I love being able to just tell Windows to share a folder and imediately have these personal files on the Linux box (and with R/W access), but I don't want these files to be deletable or even accessible from the internet. I'm not even being asked a password! Can people all over the world access my shared folders without a password too?
The topography is: One machine Windows XP SP3, the other Linux Mint Debian edition, and both connected to the internet (and to each other) via a router that my ISP gave me. It has WPA-encrypted Wi-FI, but I connect these two via LAN cable.
Am I secure in my usage of Windows' file sharing (maybe by being behind a router)? Do I have to do something?