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Login with a Public Ed25519 Key

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Re: Login with a Public Ed25519 Key

#81

Post by dcow »

Zamicol wrote: post #76
_pzht wrote: post #47

Earlier quoted context omitted.

Because it was in reply to my earlier comment saying this is not SSO. People seem to think these signatures can be used on multiple websites (sign in with Google like functionality). That's not the case. These signatures are meant to be used to authenticate to a website. If multiple websites implement this idea, then end users should have multiple key pairs (one for each site). So there would be no way a signature fo…

Are you the author? If so I would love to talk with you more about your vision and goals. I personally would like reusable keys, and I agree namespace or some other mechanism is needed. I generally prefer to link my identity among websites and I'm generally not concerned about anonymity or privacy. "A key for each website" is nearly worthless to me. The ability of others to spoof my identity because a website uses pa…

I too am interested in the small slice of the problem that is replacing passwords with something asymmetric. The rest is kinda out of scope IMO. OPAKE is cool but definitely not less complicated than WebAuthn and doesn't do anything related to solving phishing and tracking etc. either. Keys seem like a natural solution. WebAuthn is actually really good but browsers don’t yield enough control for people to use it in a portable identity style, which I also agree isn't the devil.

Re: Login with a Public Ed25519 Key

#82

Post by octoberfranklin »

md_ wrote: post #72
dcow wrote: post #70

Earlier quoted context omitted.

Because for consumer auth we just go back to the CA oligarchy and client certs nobody uses if we rely on trusting vendor attestation. I understand for a corporate setup employees are threat vectors. But that depressing outlook isn't how most people view the consumer space. We want: consumer x signed this auth challenge. We do not want: authority Y said consumer X signed this auth challenge. That’s just CA SSO style o…

It depends a lot on the situation. I think it’s reasonable, for example, for banks who have different liability standards depending on how transactions are authenticated to require batch attestation. But like I said, most consumer IdPs aren’t doing attestation checks, and it’s discouraged, so I think you’re making a big deal of it. :)

I had a Bank of America token-card (the one with the LCD display and button) until they discontinued it. Those things are fine. It was no larger or heavier than their ATM card, and in fact some banks combined the two into a single card. There was no need for any FIDO-like standardization or certification authorities there because the same entity (the bank) had provided both ends of the authentication conversation (the token card and the bank's website).

If a bank feels the need to control the hardware I use, they must provide that hardware. Their needs absolutely do not entitle them to impose codesigning/bootloader-locking requirements on my other devices, such as my phone or my laptop.

> aren’t doing attestation checks, and it’s discouraged

That will change. If it weren't, they wouldn't have bothered putting it into the spec. Or they could have used symmetric cryptography for attestation, like the bank-issued token cards and the chip in your chip-and-PIN card do.

Re: Login with a Public Ed25519 Key

#83

Post by md_ »

octoberfranklin wrote: post #82
md_ wrote: post #72

Earlier quoted context omitted.

It depends a lot on the situation. I think it’s reasonable, for example, for banks who have different liability standards depending on how transactions are authenticated to require batch attestation. But like I said, most consumer IdPs aren’t doing attestation checks, and it’s discouraged, so I think you’re making a big deal of it. :)

I had a Bank of America token-card (the one with the LCD display and button) until they discontinued it. Those things are fine. It was no larger or heavier than their ATM card, and in fact some banks combined the two into a single card. There was no need for any FIDO-like standardization or certification authorities there because the same entity (the bank) had provided both ends of the authentication conversation (th…

The nice thing about FIDO is that I can use the same USB key for a bunch of different websites. I have a single key on my keyring, and I use it for Github, for my brokerage, for Gmail, for my work, etc.

And the reason I can do that is because my work cares that I use a FIPS compliant key, but nobody else does—because consumer RPs don’t do this.

Have you encountered any consumer RP enforcing attestation? Or is this concern of yours totally speculative?

I don’t know what this Bank of America card you refer to is, but presumably it was phishable auth, since it had an LCD key? Without a standard supported by user-agents, I don’t know how someone would enforce an out-of-band/unphishable auth mechanism like FIDO+Webauthn on their own, but I’m curious to hear you explain it!

Re: Login with a Public Ed25519 Key

#84

Post by Zamicol »

redleader55 wrote: post #3

This is very likely insecure. A malicious web site could replay your Auth flow to another website where you have an account that uses the same keypair.

It's the same for passwords.

The advantage is that your private key can't be leaked on a third party website.

Re: Login with a Public Ed25519 Key

#85

Post by Zamicol »

jazzyjackson wrote: post #5
redleader55 wrote: post #3

This is very likely insecure. A malicious web site could replay your Auth flow to another website where you have an account that uses the same keypair.

right, would be better for the site to encrypt a one-time-use password with the public key you've, then all you have to do is decrypt it and log in, proving you possess the private key does this have a name? always seemed like the obvious way to do it but I've never implemented auth edit: I guess this is similar to a challenge/sign/verify signature scheme like webauthen, but is it inferior in some way?

PoP, Proof-of-Possession.
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