[foaf-protocols] Why SAN?

Nathan nathan at webr3.org
Fri Sep 17 17:41:49 CEST 2010

Melvin Carvalho wrote:
> On 17 September 2010 16:41, Nathan <nathan at webr3.org> wrote:
>> Hi All,
>> I'm not suggesting anything change, but I am interested to assess
>> whether we *need* to put our WebID in our certificate(s)? This is fairly
>> subjective in that it wouldn't work with the way the WebID protocol is
>> mapped, but if subjectAltName had never been thought of, would all the
>> constraints which make WebID what it is still be valid if we passed our
>> WebID by some other means..
> Your public key is a globally unique identifier.
> The verifying agent needs to pointer as to where to look for your WebID.
> SAN seems the logical choice.

Indeed, SAN, or more accurately "in the certificate" is the logical 
choice (personally would still prefer a dedicated x509 extension rather 
than reusing SAN but that's a different issue) - however does it make a 
difference, all that's needed is that the verifying agent knows the 
WebID & public key and has done the TLS thing to prove 
(owner/holder)-ship of said public key.

> What "other means" could be suggested?

Well as an example (not necessarily a good one) you could pass your 
webid in an HTTP header over HTTP+TLS. Even though this isn't the best 
example, the point is to figure out whether everything could still work 
without breaking anything fundamental, if so then when it comes to 
mapping WebID to other +TLS protocols now or in the future then a good 
example may pop up and we'll know a priori if it's an option to have 
WebID transported outside the certificate.



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