pam_usb/doc/FAQ

====== Frequently Asked Questions ======

> Q: Can I use my USB drive as usual ?
>> A: Yes. pam_usb only occupies a few kilobytes of the device's space.

> Q: What if I lose or break my USB key ? Will I be able to log back in ?
>> A: Sure. Your usual password will be asked.

> Q: How is the USB key identified ?
>> A: The USB device is both identified by its manufacturer attributes (vendor,
product, serial number) and by a few random bytes called one time pads that
pam_usb writes and updates on the USB device upon authentication.

> Q: What if someone copies the content of my flash drive ? Will she/he be able
to log into my account ?
>> A: Even if that person manages to fake your device's attributes (vendor,
product, serial number, UUID), the one time pad they copied will be outdated as
soon as you authenticate.

> Q: Is my USB drive compatible with pam_usb ?
>> A: About every USB flash drive will work with pam_usb.

> Q:  I can't authenticate anymore, pam_usb gives me the following error: Pad
checking failed. What should I do ?
>> A: It's a machine/device synchronization issue. To get rid of that error you
have to reset the pads of your system by removing the .pamusb folder located on
your home (/root/.pamusb/, /home/foobar/.pamusb/, etc).