I'm not giving reddit my phone number, I get enough junk calls as it is.
Edit: Reads comment by Maxburn, googles TOTP and Authy
Why the heck do I need a 3rd party involved? Ugh
Edit: Reads comment by Maxburn, googles TOTP and Authy
Why the heck do I need a 3rd party involved? Ugh
RSA was a big one that was similar. Not sure if it's still used today but there was a little hardware fob that wasn't connected to the internet or anything, the whole thing works on Time. The only thing that fob needed was a constant battery power, if it died you'd have to replace the battery and call the helpdesk to get it resynced with your account. The only thing your phone needs is a good time source like GPS or network time. I believe authenticator app works even if your phone doesn't have service. You could be on a landline in a remote region with no Internet, talking to your significant other on the other side of the world, have them log in to your account and give them the code displayed by the authenticator app and they could send that important email you forgot.
Those apps keep track of it for you, you can use any 2FA app that supports TOTP. You could even make your own if you want.
Google authenticator exists, but I'm trying to get google out of my life. I think Bitwarden has one. I'm only using Authy because it was among the first to offer a backup/restore solution that I stumbled on.
Have a look at Yubikey's - there, the seed is stored on the key itself, the calculation done on the key itself, and all the app does is read it all via NFC.
Yes, you use the Yubico Authenticator app, but it's entirely local only (runs fine with all networking switched off).
It's available for Mac, Linux and Windows, as well as Android and iOS. On computers your key needs to be inserted into a USB port. For Android and iOS I use the NFC key and I just scan it against the phone after launching the app.