(This is NOT an official Mozilla project and does not in any way reflect the views of my employer.)
Mozilla Persona is a way for users to use their e-mail ID as their identity on the web. While cool, it will only really take off when existing services that people use become Identity Providers. XMPP (Jabber) is a widely deployed IM protocol whose IDs look like e-mail and it is a secure, federated system in alignment with Persona’s goals. I thought it would be really cool if I could log in to Persona enabled sites using Jabber IDs. I’d like to announce browserid-xmpp which does just that.
It should work with any XMPP server that supports components and BOSH. That said I have only tested it on my VPS (with Prosody, ejabberd and Openfire), so any issues and pull requests are welcome, as is a quick comment if you deploy it on your server. You’ll also need a relatively sophisticated web server like Apache or nginx to serve the browserid file with the right Content-Type. CheckMyIdP is a great way to check if everything is setup properly.
browserid-xmpp is two things. The first is a XMPP component that can plug into any XMPP server and answer a certificate signing query. This is a fork of the “official” browserid-certifier with an Jabber-RPC front-end rather than a web service.
The second is the set of provisioning and sign in pages that can be re-used by any domain. The authentication is handled as a two stage process using BOSH. This was my first experience with BOSH and it is ridiculously cool how it works and supports session hand-off to another page, without which this would not be possible. On the sign in page, an XMPP stream is established and authentication is done using standard XMPP authentication. The established BOSH stream has a session ID and every message sent has an incrementing request ID. On successful sign in, the sign in page sticks these two, along with the JID into
sessionStorage. The provisioning page reads these out and ‘attaches’ to the existing BOSH stream. Due to the unpredictable nature of the SID and RID, there is a reasonable guarantee that someone who attached to the stream successfully knew about the stream before. The provisioning page then makes a Jabber-RPC call over the same stream to the XMPP component. This call is performed on behalf of the JID and a certificate is sent back to the browser. You are now signed in!
P.S. I’d like to thank Cory Benfield for an excellent guide to writing an IdP.
P.P.S. This post was published right before a 12-hour plane ride, so I’ll be back for tech support in a while.