[OpenID] Xrd signing with username token

[SitG Admin]

>I know you were once challenged by XRI.

The guts of it are still a bit beyond me (as is, frankly, much of the 
OpenID spec), but I do have a strong grasp of the theory now. The 
discussion (on this list) about signatures, so far, has seemed to lie 
well inside the technical territory, so I've mostly been staying away 
from all that.

-Shade