I often forget the keys to my lab, so last night I was thinking of making my N900 my key. One method I had in mind would be to simply put a security token on the mass storage and have a PC check for this token but I often use the mass storage so the token may inadvertently end up on PCs or other USB sticks. Though I'm sure the students would not use it if they ended up with it. The other was to check the USB serial number in addition to the token file.

At one point I thought about voice recognition with the password being "Omelette 'du' fromage"

So my question is, how easy is it to clone a USB serial number or am I fairly safe in using it?

If I'd have been your student I WOULD have used it, just to see if it actually works. What I had done next depends on how much I liked you.

That depends on what you mean with "clone". To retrieve it is very easy as you surely know. But manipulation the serial number of another device should be impossible unless you're a manufacturer. So the question is how safe is the application on your PC against "usb serial injection" from another source (e.g. a text file that contains your serial number).

btw:
Do you really want to wear your USB port for a simple authentication gimmick?

Thanks Sulu, I'm sure you wouldn't trash my lab . I didn't think too hard about how it might be bypassed like that so I have no idea how hard it would be to fool the application to be honest.

My USB port seems pretty sturdy but I would only be using this if I forget my keys so it wouldn't be any more frequent than charging. I use a wall charger too (3 batteries) so I don't charge from it either, it's little used.

My N900 is the only thing that I try to always have with me other than my wallet and keys so when the keys aren't there the only other thing is my N900, that and the gimmick is the reason I thought about using the N900

I guess I might just chicken out and get a combination lock or something. It also means I can't let any students in remotely but that's not as important, just me being lazy.