Login with a Public Ed25519 Key
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Login with a Public Ed25519 Key
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Re: Login with a Public Ed25519 Key
#2> Much simpler than webauthn.
Having recently had to upgrade from u2f to webauthn, the complexity involved in getting webauthn right cannot be understated, especially when comparing it to something like OTP.
This flow seems simpler but more annoying for the end-user, right? They would have to generate the signed message themselves and then paste it into the browser. Whereas with webauthn you just touch your security key.
Re: Login with a Public Ed25519 Key
#3This 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.
Re: Login with a Public Ed25519 Key
#4"Much simpler than webauthn" Is it? Trying out https://webauthn.io/, I can log in using a security key without hitting the command line and copy & pasting some base64 string.
"Private keys never leave end users' devices" How does it guarantee that, considering it saves the private key in the file system? It can be trivially copied off device from there.
The examples also appear to encourage key reuse, and since the challenge is the current time, the signed auth message can be replayed against any other site where the user set up using the same key.
Re: Login with a Public Ed25519 Key
#5This 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?
Re: Login with a Public Ed25519 Key
#6It's an okay-ish alternative to a password, but if we're going to use cryptographic secrets for auth, I'd hope to see more of a handshake and challenge-response involved.
As it stands, anyone who has access to a private key momentarily can generate any number of tokens for use, practically indefinitely (just sign a timestamp for every second for the next N years). This system is open to replay attacks as well.
It also glosses over the entire problem of trust establishment, cert revocation, etc.
Re: Login with a Public Ed25519 Key
#7This 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.
Yeah, there's no verification of a server's pubkey like ssh (which mostly is trust-on-first use), or a cert chain like tls.
This seems like a cool proof-of-concept. There are also a bunch of security properties that it fails in.
Re: Login with a Public Ed25519 Key
#8This post has ironically convinced me to use WebAuthn instead.
Re: Login with a Public Ed25519 Key
#9This 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.
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Re: Login with a Public Ed25519 Key
#10This 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.
Why would you use the same keypair for multiple sites?