This isn’t strictly a privacy question as a security one, so I’m asking this in the context of individuals, not organizations.
I currently use OTP 2FA everywhere I can, though some services I use support hardware security keys like the Yubikey. Getting a hardware key may be slightly more convenient since I wouldn’t need to type anything in but could just press a button, but there’s added risk with losing the key (I can easily backup OTP configs).
Do any of you use hardware security keys? If so, do you have a good argument in favor or against specific keys? (e.g. Yubikey, Nitrokey, etc)
I am very confused what you mean that a phone doesn’t count as a 2nd factor.
Your password is factor one.
An OTP is factor 2, whether it is on a phone or a yubikey makes literally 0 difference practically. It is a “something you have”.
If you need biometric unlock to get into your 2fa app or on the yubikey itself, that is a 3rd factor of “something you are.”
If you are very worried about someone compromising your phone app and already knowing your password, (which is not how 99% of intrusions are done) then put a pin or fingerprint on your 2FA app and it is back to being a secure 2nd factor.
The probability of someone breaking into your phone, hacking your bitwarden password, and having a fingerprint exploit that allows them to break into your 2FA app is like 1 in 1 billion unless you are like top 1000 most important people in the world. But as a thought exercise, a dongle indeed has the potential to be more secure because it is an additional “something you have” to your phone.
The idea is that your passwords are stored on the phone. You want a separate long random password for each account, so it’s unfeasible to remember them. It’s also a big pain to type every one such password on a screen keyboard. Thus, the password and the phone are the same factor.
I have avoided having important passwords on my phone because of this, but some people use their phones more heavily than I do. My more important accounts are only accessed via my laptop, using a TOTP phone app as 2nd factor. I rarely take the laptop out of the house.
But this is only the case if you store your passwords in a plaintext file on your phone. Something that I hope nobody would be dumb enough to do, but I guess many people would.
If you have an encrypted password manager like Bitwarden or so where you have a single long password to open and get at your other long secure passwords, then it is essentially a different factor than your phone, right? Since having the phone unlocked would do nothing to help the attacker get to your password vault.