Isn’t the value of two factor auth that it requires a physical device (your phone or computer) with the auth key to authenticate you? Then why don’t many two factor auth apps seem to support syncing? If it’s fine to do so, are there any open source cross platform apps that sync keys?
Aegis w/ auto backup + syncthing
Ente Auth
F-Droid: https://f-droid.org/packages/io.ente.auth/
You can easily self-host it:
https://help.ente.io/self-hosting
You can create TOTP for login records in bitwarden and sync it of course. But make sure you protect your wallet key with additional security methods.
Many people have a warped understanding of what “two factor” means.
They conflate it with devices and they think it means that one of the factors (why one? which one? who knows) needs to be restricted to exactly one device.
What “two factor” really means is that you should have more than one required factor of authentication so that if one is compromised the attackers still can’t get in.
Ideally the factors should be spread across the “something you know” / “something you own” / “something you are” categories to complicate the manner in which they can be compromised.
We can only reliably rememeber a limited amount of passwords, so like it or not we have to use some devices at least some of the time.
The trouble with “something you own” is that it can be lost or damaged or stolen, and if you only have one of it then you’re fucked. So adding some redundancy is not a bad idea.
The larger issue is that everybody is stuck into extremely rigid and outdated mindsets that date back decades. “Two factors” don’t have to be exactly two, and they don’t have to include exactly one password, and so on. It should be fine if you wanted to secure your account with 3 passwords, and should be up to you if one of those password is a barcode tattooed on your taint so you need a mirror and to bend upside down to scan it.
Bottom line, use whatever you want and use your best judgment as to how secure is each factor. If you want to use something that syncs to multiple devices, go ahead. What you should consider is who has access to those devices and how it would affect you if they’re lost or stolen.
There is the completely open source https://standardnotes.com/ which would support that via their syncing and the authenticator note type.
Unfortunately it does not look like their free plan allows you to use that note type. So could also host it yourself though (and pay for the premium token their or hack it out - it’s foss). Have never done that myself though
