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Openid Sequence diagram -was: Position Paper for W3C Workshop on Identity

From: Henry Story <henry.story@bblfish.net>
Date: Thu, 21 Apr 2011 17:05:29 +0200
Cc: public-xg-webid@w3.org
Message-Id: <214F0BDB-8112-427A-8750-B01F43457BC1@bblfish.net>
To: peter williams <home_pw@msn.com>

On 21 Apr 2011, at 15:32, peter williams wrote:

> I don't find the openid argument at all convincing (even it its 100
> handoffs).

At all? Surely that is a pose. :^)

> Its not a relevant factor. I have every intention of accepting
> openid (from google), via the Microsoft ACS bridge for a year (to see if
> anyone cares about using Google IDs in real estate, understanding that
> Google just exited its real estate business venture, which lost money). That
> bridging adds several more handoff steps... and thus the metadata resolution
> that assures the endpoint of the bridge adds several more, too. The
> connection and packet load on the consumer PC with broadband is trivial
> compared to the connection and packet of the average blog page, and is lost
> in the noise. (I have 100 logins a minute to process.. and have to calculate
> accurately)

Having worked at AltaVista I can tell you that the criteria of efficiency weighed very 
heavily there. Anything that delays a page download reduces the number of people coming
to a site, and the number of visits. The work that was put at the early AltaVista in keeping
the front page light was key in its success. Then the marketing people came over and decided
to over rule the creators and turn the front page into a big billboard for DEC, then Compaq
creations. They zoomed into the Portal bandwagon and never recovered. Notice how Google's front
page is very light?

Facebook decided not to use many  well known vocabularies because apparently of the cost 
to add the namespace to the  html. Ok, you may think that's not serious, but it is an argument 
that is often used. (I hope I never hear you use such arguments in the future, now that I know that you 
don't think that efficiency is important)


> In a metadata driven world, its just not relevant to count pings in an
> handshake. One accepts that the first token delivered to setup a crypto
> session is relatively expensive (and then one uses token caching for
> subsequent method calls, based on crypto sessions, as in
> ws-secureconversation at layer 7 - or SSL at layer 4). This is what SSL
> engineering proved as effective (where the SSL sessionid is just a token).
> In the web world, that token is the cookie (of course).

In linked data driven world where you are crawling across web sites, jumping from
one site to the other just to fetch a resource, things look different here.

> The analysis is not even correct. In openid, to be *assured*, the IDP has to
> ping the RP's XRDS file (i.e. impacting my server farm's TCP queue) - to
> test from the metadata that the audience is STILL authorized to receive the
> IDP's assurance.

Oh, so I have missed 1 connection? At which point in the sequence diagram here is it?
http://blogs.sun.com/bblfish/entry/the_openid_sequence_diagram

Is that because this was describing an old version of OpenId? I thought I had read it 
quite carefully at the time. But I was probably just reading some synopsis.

Is there a correct sequence diagram for OpenID we can see?

(I am not asking rhetorically, but would genuinely like to know the answers to those questions)

> Then, it has to verify the XRDS endpoint's assurance (using
> https cert chain, which means walking the cert chain and pinging the
> OCSP/CRL endpoints of each element, in the general case).

Ah you mean in step 9 of my diagram. It has to verify the TLS connection.
yes, well clearly if OpenId is to be secure it has to do 5 more connections, or 
according to you 6 more. Given that these connections have to be TLS based, things
get to be expensive.

> If DANE was used
> instread of OCSP, n UDP pings have to be made against the DNS server
> instead... to walk the zone chain(s), which requires n pings against the
> root servers.... So the count suggested for openid is not even accurate. Its
> not a valid characteristic. 

Yes setting up all those TLS connections is not good. It is what makes other things
impossible later.


> We are passed scoring points. 

I think large companies will want to be counting these very carefully. And 
so will linked data servers. Efficiency there is very important.

> If one wants to compare, discuss the core differences between any and all
> websso scheme and their use of metadata for assuring endpoints.

Oops that would bring us into talking semweb. I was told we should not talk
about that. It frightens people.

> The websso
> world solves the browser inadequacies by making the browser irrelevant (as
> the signaling is site to site, using the browser as a communication bearer,
> only). WebiD believes (right or wrong) in the browser as king (not as a
> transfer agent between sites). This is what you need to be saying. Whether
> or not that argument is convincing... is a different issue.

yes, we could emphasise the peer to peer nature of WebID. But as this is a
talk aimed at browser vendors...

> 
> 
> -----Original Message-----
> From: public-xg-webid-request@w3.org [mailto:public-xg-webid-request@w3.org]
> On Behalf Of Henry Story
> Sent: Thursday, April 21, 2011 5:41 AM
> To: Kingsley Idehen
> Cc: public-xg-webid@w3.org
> Subject: Re: Position Paper for W3C Workshop on Identity
> 
> 
> On 20 Apr 2011, at 23:08, Kingsley Idehen wrote:
> 
>> Henry,
>> 
>> Very nice!
>> 
>> Observations re. diagram:
>> 
>> 1. step #2 is missing arrow (inbound) from "resource server" to Bob's 
>> browser is missing re. authentication challenge 2. step #3 is missing
> arrow (outbound) indicating what happens after "OK" button is clicked.
>> 
>> Re. OpenID, accentuating OpenID+WebID will help i.e., implying that OpenID
> implementers benefit immediately from WebID. It's less politically thorny
> than implying OpenID is inadequate (even though we know it is etc..).
> 
> yes, that us because it all happens in 1 TLS connection. 
> 
> Is this better?
> 
> 
> 

Social Web Architect
http://bblfish.net/
Received on Thursday, 21 April 2011 15:06:04 UTC

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