Things I learnt about passkeys when building passkeybot

I read as much about it from the official sources as I could about a year ago, so I might be wrong here. From what I remember even though no specific mention of Android or iOS attestation was made, a "strong" form of 2FA is needed. Stronger than TOTP.

In my country most banks I talked with require a mobile app for 2FA even if you're logging in from a desktop browser. I haven't (and will not) install a banking app on my phone, so I'm not sure if it would work if the phone doesn't pass the attestation (e.g., Play Integrity on Android). I wanted to install the app in an AOSP VM, but no bank would even send me the apk file - they all want me to download it from Google for some reason.

Another option was to pay for a hardware device from a third-party company.

I was lucky that one bank still uses SMS 2FA. It's weaker than TOTP (depending on your threat model, I guess), but I prefer it.

My other option is either to:

* have a smartphone;

* have an "approved" OS from an American company;

* have an account with said American company so I can download the app from the company's repository;

* run closed source software on my smartphone.

or to

* pay for a USB device from a third-party company;

* that barely works with Linux;

* that requires a closed source program to run;

* that doesn't work with VMs and troubleshooting was a pain (I tried).

What I want is to use TOTP. I would actually store the secret on another device, as I'm not opposed to the idea of 2FA in general. And I would be fine if my money were drained as a result of me being hacked. If I had millions in my account, I could just use a separate computer only for the banking, but still a computer I chose.

Online banking (a superset of "mobile" banking) is very important for a person to have in order to participate in society. The ability to choose what hardware and software to use is also very important. The ability to not associate oneself with third-party companies, to accept their ToS and to pay them money is also very important. Therefore, I think those things should be my rights. I'm not complaining about a gym or a pizza place requiring a mobile app here, after all.

[0] https://en.wikipedia.org/wiki/Strong_customer_authentication

Safari on iOS can store and use passkeys from any app that implements the right system API, including the default Apple Passwords but also Bitwarden and Chrome.

For desktop, you can either use a browser extension provided by some password managers (such as Bitwarden), or if you're on a Mac, Safari and Chrome can access passkeys from other apps similarly to on iOS (but not as many providers support this API on Mac as on iOS, and in particular Bitwarden doesn't, so you'd have to use the extension for that).