@ryanrowcliffe : thanks for your kind response.
I fully agree that if software (instead of the user) checks the website name (domain name) before submitting *any* credentials, is a perfect solution for most of the "fake site" attacks (except https://infosec.exchange/@ErikvanStraten/112914047006977222).
Unfortunately passkey implementations are insufficiently mature for the masses (I'm not talking about my *personal* situation). And I do like passkeys, but they must work flawlessly before I'm going to advise anyone to use them.
People who never used a pw manager will *not* install one to use passkeys. On their tablets and smartphones (marktshare increasing) they'll use Apple's or Google's.
During my research I found at least three ways to fully unexpectedly lose access to part or all of one's Android passkeys:
1) The unexplicable and fearsome Android screen reading "Your encrypted data is locked on this device" (Google it or see https://infosec.exchange/@ErikvanStraten/113730072998238596) when trying to use passkeys. This is a long time bug that, afaik, has not been fixed.
2) For privacy reasons, setting up a passphrase for Chrome sync is a good idea. However, if you ever want to change or remove that passphrase, Google directs you to the bottom of https://chrome.google.com/sync (see the screenshot below). Tapping "Delete data" will delete ALL of your passkeys (on all your Android devices) without warning. Note: this text notably is the "fix" made by Adam Langley in response to my post to https://seclists.org/fulldisclosure/2024/Feb/15 (after wasting a long time after my bugreports to the Google and Chrome team): before it read "This won't delete any data from your devices".
Note: it appears to be a misconception that passkeys are synced from your device(s) to the cloud. They're cloud-based and sync to your devices. Google stores the encryption keys and, afaik, generates them on their servers. Furthermore, bugsolving is hampered by the fact that both Google and (separate) Chrome teams have to handle them.
3) If you have more than one Android device, you may run into the situation where your passkey's private keys are encrypted using *different* encryption keys. They will sync fine to other devices, but are unusable on them (see my FD post). I've not tested this for quite some time, so this issue may have been fixed (if Google did, they didn't bother to notify me).
Google online help is horrific: https://infosec.exchange/@ErikvanStraten/113730722652512878.
Edited 12:10 UTC to add: a somewhat acceptable translation from Dutch to English of my writeup "Passkeys for laymen" can be seen by opening https://www-security-nl.translate.goog/posting/798699/Passkeys+voor+leken?_x_tr_sl=nl&_x_tr_tl=en&_x_tr_hl=nl (it appears to work in Chrome, looks like a phishing link and has a certificate with a zillion of different domain names
). The original article, in Dutch, can be seen in https://www.security.nl/posting/798699/Passkeys+voor+leken.
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@agl