Your basic idea of using Linux to more-securely cruise the Interwebs is a good idea, and many people do just that. I appreciate your caution but for the most part I don't think that you will have any of the issues you are imagining.
Beepster
Ruben
The only danger would be that you would inadvertently copy it to your Windows partition which might allow the infection to run the next time you boot Windows.
Hi, Ruben. You'll have to excuse my ignorance here but how would that happen? It sounds like I would almost have to manually move that file over.
That's pretty much what I was referring to - that you might manually save what you thought was a safe file to your Windows partition and the file turns out to be infected. As I mentioned (and Dub also indicated this) that can't happen if you don't allow Linux to mount your Windows partition.
Beepster
Like say my Windows partition had a nasty virus that actually wanted to attack my Linux partition and steal my passwords or whatever AND I had an AV installed on the Linux partition (which I will) AND I'm using FF for Linux with scriptblockers (which I will)...
First of all, Windows OS cannot natively read a Linux partition, so any program (good or bad) running within Windows cannot access (i.e read data from) your Linux partition. I'm sure there are viruses that can access any drive partition but they would have to work at a low-level disk function, as in a virus that could delete your MBR or all of your your partitions. But such a virus would still need run on the host OS, so in your scenario, the virus would need to run on Windows but be able to read from the Linux partition, navigate the Linux file structure, find the encoded password files, and decode them. I'm sure technically that could be done, and there are third-party apps that allow Windows to read from a Linux partition, but that's asking a lot from a virus - it's much easier for all of the script-kiddies to just write viruses that turn your computer into a
zombie. And as Dub mentioned, Linux is fundamentally a more secure OS than Windows.
No one can give you a guarantee, but as I mentioned above, it's fairly common for Linux users to do what you are wanting to do for the same reasons. And with your cautious/guarded approach to using the Internet I think you will be at less risk, not more.