Applications like WordPress, Truecrypt, SquirrelMail, and Google Apps could keep the information on 2 Yubikeys.
ie) In the picture of WordPress you are asked for a
Username,
Password, and
Yubikey OTP.
A spot for an
optional Alternative Yubikey OTP could easily be added in.
By giving the option several things happen (well, at least for people with 2 or more Yubikeys).
-It wouldn't be a big concern if a Yubikey is left at work, that's if you also kept one at home. Because you'd still have access.
-Losing a Yubikey wouldn't mean a big hassle. You could log in to the few applications that you use and remove the lost Yubikey and later put a new Yubikey OTP in when the new one arrives.
-This could also allow the use of both a Personalized Yubikey (with a self-assigned OTP) and also a standard (Yubico issued) Yubikey OTP.
-Gives the option of putting a Yubikey away with will, or in a safety deposit box etc...
-Allow the sharing of services/programs in a secure manner. A kind of joint account between husband and wife.
-People (
who think ahead) may purchase 2 Yubikeys instead of just one, or may be more inclined to purchase a second one later on.
True enough not everyone would put a second Yubikey OTP in, some people are ultra-paranoid etc...
But not everyone see's the world as a Red Alert 24/7, some people see security in terms of:
normal, low, medium, high.
Since it is just an option, it should not pose a problem for the average person and using the average application.
It could give more a sense of security for the average user who may leave the Yubikey at work, or is concerned about losing the Yubikey.