How AuthLite uses YubiKeys
YubiKeys have a variety of capabilities, and AuthLite only uses some of them. But this may limit other things you want to do with the same YubiKey.
OTP Slots
Each YubiKey has two "configuration slots", each of which can be used for an OTP generator, a Challenge/Response secret, or a Static Password. AuthLite normally uses both configuration slots. This has some implications:
- You can't use an AuthLite-programmed YubiKey for other online services that use OTP mode. (U2F services are still fine).
- You can't use the same YubiKey for more than AuthLite domain, because sharing the OTP secret of an event-based device between domains ruins the security.
- If you won't ever need the YubiKey to work with cached/offline logons, you can choose to program only one slot for AuthLite, leaving the other one for something else. But this leads to problems because triggering one OTP slot vs. the other is a matter of how quickly you press and release the contact switch. This leads to confusion among users and the feeling that the service isn't working very reliably.
FIDO/U2F mode
At this time AuthLite does not use U2F, but the YubiKeys still support it. Due to the nature of U2F, you can use it for as many different services as you like all at once. U2F does not "take up" a configuration slot, and is not affected by the programming of the OTP/challenge-response slots at all.
PIV Smart card/certificate mode
AuthLite does not use the smartcard/certificate feature of YubiKeys at all, but you can still choose to use this feature for something else not related to AuthLite. It does not "take up" a configuration slot, and is not affected by the programming of the OTP/challenge-response slots at all.
Some YubiKeys sold by AuthLite may have the smartcard feature disabled by default. You can turn it back on in the YubiKey Programmer by changing the USB mode to 6.