Google also allows you to use google authenticator, but I don't believe they all...

lorenzhs · on Dec 15, 2016

You can use any TOTP app you like, they all use the same QR code format. You can even build your own, it's all well documented.

jsudhams · on Dec 15, 2016

Google does allow other apps (I think it is still same as GAuth) SASS pass and other authenticators with good. But yes they don't allow other token provides like Yubikey or RSA fobs

lorenzhs · on Dec 15, 2016

Google is one of the major proponents of U2F, which is based on hardware tokens. Yubikeys support it, either the cheap U2F-only one or a Neo / 4. I use it and it works flawlessly. At the moment, only Chrome implements the required APIs as far as I know, but Mozilla is working on adding it to Firefox.

brennen · on Dec 15, 2016

> But yes they don't allow other token provides like Yubikey or RSA fobs

I think this is incorrect, at least provided you're using Chrome. The implementation was buggy somewhere in the chain the last time I tried it, but it's there.