[I was at Mozilla during the development of BrowserID but I didn’t work directly on it. I was a huge fan of the effort.]

Besides non-obvious UI issues, there were fundamental issues. One in particular that was very hard to overcome:

Very few people would choose to hide which websites they are logging into from the identity provider. People don’t care whether their IDP can see when/where they are authenticating. That’s assuming they could even understand the issue at all. They have to trust the IDP a lot either way, and this one detail is small, counterintuitive, and even oxymoronic to most people—Trust the IDP 99%, but jump through hoops to avoid trusting them 100%? Why?

There is value in the identity provider knowing when, and from which device, and from which location, and on which websites you are using the identity. Hiding any of this from the IDP hurts security. It is really hard to overcome this in a useable way. A lot of purported solutions implicitly assume users have device and key management abilities that even experts in this area rarely consistently practice.

So, then, are you really better off, i.e. receiving a net positive benefit?

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wakamoleguy 2 hours ago | parent | next [-]

That’s real, yeah. I also remember a couple concerns around that privacy as well. One being that if your IdP controls your email, they could probably figure out what sites your communicating with anyways. And perhaps a timing issue with when relying parties fetch the public key to verify assertions?

For bespoke projects, a lot of the privacy concerns go away once I’m using my own authentication in the first place (I control the full stack). So then the value would come more from federation (which is hard to bootstrap) or developer experience. I do still think BrowserID has something going for it there, potentially.

I do wonder if I’ll miss the centralized session management, though. I’m building this IdP to be modular, so I could try a different protocol on top of the user management core down the road.

Thanks for sharing!

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stavros 6 hours ago | parent | prev [-]

Sorry, I'm confused. What are the hoops? Wouldn't this be solved by Persona just telling the IdP the URL of the site to auth to?

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wakamoleguy 3 hours ago | parent [-]

The biggest one I’ve come across is the ability to manage and revoke sessions from a centralized location. With BrowserID, you can’t just sign out of your IdP and expect all relying parties’ sessions to invalidate. Instead, BrowserID asserts that you controlled the email at a point in time, and then it’s up to the site to decide how to manage the session afterwards.

3rd party cookie blocking makes this worse, since it’s difficult to silently refresh your session by checking with the IdP behind the scenes. I believe Auth0 uses a hidden iframe for this, which uses 3rd party cookies and looks a lot like a tracking pixel. Without that refresh mechanism, though, relying parties are pushed to have longer lived sessions, which makes the lack of a global revocation worse.

	▲	stavros an hour ago \| parent [-]
		Ah, yes, but that's a problem all IdPs have, no? You have to check in with the IdP every so often. I don't think this is insurmountable, Persona could have just added a mechanism to do that.