Do you not want the identity provider (e.g. Google) to know every place you log in? (This was something Persona solved, alas...)
Do you not want to be reliant on a megacompany like Google whose spam filters might someday hit a false positive, causing Google to ban your account, and there's nobody to call and you're locked out of everywhere?
Or is it about separation, i.e. you don't want any single notion of your identity to have too much power if compromised (and you're careful to use unrelated credentials, e.g. distinct passwords, on every website)?
Indeed, those are some excellent reasons to avoid any centralized login system. :) Most people won't care, but early adopters might. Startups don't need to care about early adopters after the 'early' stage, but the early stage is critical, so it's just something to keep in mind.
Are you ok with the way that GitHub and Ubuntu outsource the storing of credentials to authenticate a "push" by checking against a public key, for which only the user holds the private key? What if more services worked this way?
That'd be lovely. Unfortunately the key management problem hasn't really been solved: there's no way to make it easy for average users to create a key and use it on a bunch of different devices. "What you know" (a password) is still way more convenient than "what you have" (a keyfile), unfortunately.
I don't think there's any way to solve that without using a third party to sync keys across your devices. Something like that might be able to be done securely, but it'd require a lot of thought and care. (Ultimately we have to trust the service provider with our credentials anyway, so trusting them to sync keys doesn't seem like too far of a stretch.)
Do you not want to be reliant on a megacompany like Google whose spam filters might someday hit a false positive, causing Google to ban your account, and there's nobody to call and you're locked out of everywhere?
Or is it about separation, i.e. you don't want any single notion of your identity to have too much power if compromised (and you're careful to use unrelated credentials, e.g. distinct passwords, on every website)?
Indeed, those are some excellent reasons to avoid any centralized login system. :) Most people won't care, but early adopters might. Startups don't need to care about early adopters after the 'early' stage, but the early stage is critical, so it's just something to keep in mind.
Are you ok with the way that GitHub and Ubuntu outsource the storing of credentials to authenticate a "push" by checking against a public key, for which only the user holds the private key? What if more services worked this way?
That'd be lovely. Unfortunately the key management problem hasn't really been solved: there's no way to make it easy for average users to create a key and use it on a bunch of different devices. "What you know" (a password) is still way more convenient than "what you have" (a keyfile), unfortunately.
I don't think there's any way to solve that without using a third party to sync keys across your devices. Something like that might be able to be done securely, but it'd require a lot of thought and care. (Ultimately we have to trust the service provider with our credentials anyway, so trusting them to sync keys doesn't seem like too far of a stretch.)