alt Hacker News> Passkeys are better passwords. They need a TPM.
Passkeys absolutely do not need TPM.
You can get passkey support in any browser with a simple 1password plugin without any TPM hardware.
The same way you could get a TOTP app on your phone without any TPM.
TPMs are just an extra security layer for most usages.
They are mainly a necessity for some shady business like DRMs.
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TPMS give you the convenience of short passwords (or no passwords) and the security of long keys.
A chip which you can write to and interact with but can't read is valuable; it lets you enforce conditions which you otherwise couldn't. For example, you can protect your sensitive data with a 6-digit pin, secure in the knowledge that the chip will erase the encryption key after 10 failed attempts. If you had full access to the TPM storage, you could brute force that PIN in seconds.
> Passkeys absolutely do not need TPM.
They do not, but how does the service you’re using know your passkey is secure? For all they know you’re just some gullible user that clicks through every fishing email you get. You’re dumb, weak, helpless, they gotta protect you from this scary world out there, and maybe yourself as well.
They can’t do that if they allow your passkey to be stored anywhere you control. KeepassXC? The second you type in your master password the keylogger will snatch it, and your entire database with it!
Okay, maybe you’re some hot shot cryptographer, you’re using a TKey (think Yubikey, except you have full control), and there’s no way your secret key leaves it even if your main computer is fully compromised. Well, the service doesn’t know that. All they see is your public key and a matching signature.
So, sorry Mr. Security Researcher, we’re gonna have to be safe, and require you to use approved hardware only. Too many (wo)men children out there must be protected, we have no way to tell you’re not one of them, so it’s remote attestation or you’re out. What’ online buying worth for anyway, when you can just cross the ocean?
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Just so we’re clear, I agree with you here. But don’t forget there are two kinds of passkeys out there: with or without the evil remote attestation. And many companies will push for the remotely attested kind, using the exact argument I used above, except with a straight face.
Or they will just present a false dichotomy: remotely attested passkeys on the one hand, short easy to guess reused everywhere passwords on the other.