Hi Jim, 

When you say "Plasma" you are referring to "The PoLicy Augmented S/Mime
(plasma)"
https://www.ietf.org/mailman/listinfo/plasma

Correct?

To judge whether it is useful to write about that work I have to admit
that I am not fully up-to-speed with the latest status of that effort. 

Can you shed some light on that? 

Ciao
Hannes

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
> Of ext Jim Schaad
> Sent: Friday, December 16, 2011 10:01 AM
> To: [email protected]
> Subject: [abfab] Trying to get Plasma text correct.
> 
> I am starting to try and develop text for the Plasma documents on how
> to use
> GSS-API.  At least initially, I want to write it to be generic GSS-API
> and
> then do specifics for the ABFAB GSS-API/EAP case.
> 
> To make my life simpler, we are going to require that the client/RP
> transport method always be TLS.  Which means that I will at some point
> in
> the future need to worry about cases where path validation is not
> completely
> successful.  But I am planning to punt that issue for now.
> 
> So since we always know the name of the entity we are going to be
> talking
> to.  My assumption is that we are always going to pass an acceptor
name
> into
> GSS-API.  The acceptor name would be "plasma/serverName@domainName".
> We
> would say strip the left most dotted name as the server name and leave
> the
> rest as the domain name.   Thus an example name might be
> "plasma\[email protected]".
> 
> Now we start looking at some fun things.
> 
> 1.  If the url was
> https://mailPDP.windows.example.com/internalPolicyChecker, should the
> extra
> verbage be reflected in the service name string?
> 
> 2.  Do we need to say anything special about walking up domain names
> when
> doing checking or during AAA processing?  Specifically, should a
domain
> string be truncated when doing the channel binding processing called
> out in
> the EMU channel bindings document wrt to the database lookup code?
> 
> 3.  In the current code, one would expect that the client would send
> the
> full name to the RP as part of the first GSS-API handshake message.  I
> still
> feel somewhat uncomfortable with telling the RP what its full name is
> going
> to be, but I don't see any way around this with the current GSS-API
> calling
> code.  That is since I want the channel binding to occur w/ a specific
> server and domain, there is no way not to let the RP know what they
are
> going to be in advance.  I understand that the AAA system will
validate
> that
> the RP has the right to the name so there should not be any issues,
but
> is
> there any way to make me feel  more comfortable with this?
> 
> 4.  Since I am using TLS, I will need to specify that TLS channel
> binding
> will occur (and find the appropriate references about how this works
> for
> extraction).  I am still trying to debate if I need to include
> additional
> channel binding data from my protocol dialog as well.  Has anybody
> written
> any guidance on when this is recommended and what types of data need
to
> be
> included?  I think I have re-designed my protocol so this is no longer
> necessary, but I would like some assurance that I am correct.
> 
> 5.  If I get to this point, have I already selected the credential
that
> I
> will be using with the EAP server, or I have just gotten to the point
> of
> saying that I will be using one of a set of credentials?  This is an
> LOA
> question.  I will have already selected the realm that I am going to
be
> authenticated against since I know that goes out in the first GSS-
> API/EAP
> message.  I also understand that by selecting a realm, I may have
> restricted
> the set of possible LOAs that I can be dealing with.  Should my
> protocol
> allow for some type of re-start of negotiation if a different LOA is
> needed?
> I assume that would need to be a total re-start of the GSS-API/EAP
> negotiation at a minimum although I could leave up the TLS session.
> 
> 6.  Should I be setting up some type of negotiation in my protocol to
> allow
> for a different GSS-API mechanism to be selected?  I.e. if one is
> within a
> single company one could use the Kerberos GSS-API rather than going
> with the
> EAP version.  Would be think this is of importance or can I just
> restrict to
> using the one GSS-API mechanism and be done with it?  Can this type of
> negotiation be done within GSS-API?  I don't remember seeing anything
> of
> this sort but that does not mean it does not exist.  My understanding
> was
> that it amounted to configuration information on the client side.
> 
> Jim
> 
> 
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