[OpenID] Email as Identity

[Paul Austin]

I'm new to openid and as far as I can see a user's identify is a URL to 
a web site which an openid secure web site can use to authenticate a user.

What I was wondering if any thought had been given to using an email as 
the identity for a user. In this approach there would need to be a way 
to link an email address to the web page to authenticate a user. What I 
was thinking is you could use an extension to the DNS records such as 
used by the Sender Policy Framework (SPF) 
http://en.wikipedia.org/wiki/Sender_Policy_Framework. This DNS TXT entry 
would have a URL to which the email address could be passed to to 
authenticate the user. This might look something like this

mydomain.com. IN TXT "v=openid2 auth=http://login.mydomain.com"

Then when a openid secured web server receives an email address as an 
identity it would look up the DNS (if not already cached) for the open 
id TXT record and find the openID authentication url and to add the 
email to that and use it as the identity.

For example:

me at mydomain.com

would become

http://login.mydomain.com?email=me@mydomain.com

The advantage of this approach is that it is easy for a user to remember 
there identity as it's their email and would also be simple to implement 
on both sides.

This suggestion would be an extension to the current method of 
identities rather than to replace it.

Any comments suggestions?

Cheers,
Paul