W3C home > Mailing lists > Public > public-webid@w3.org > September 2012

Re: WebID questions -- was: [dane] Call for Adoption: "Using Secure DNS to Associate Certificates with Domain Names For S/MIME"

From: Melvin Carvalho <melvincarvalho@gmail.com>
Date: Wed, 26 Sep 2012 14:34:02 +0200
Message-ID: <CAKaEYhJUQoBcD1jHkr=AbERp2Jo1RQuWJ+siKHXGNjKKM8eyPQ@mail.gmail.com>
To: Ben Laurie <benl@google.com>
Cc: Henry Story <henry.story@bblfish.net>, public-webid@w3.org, Andrei Sambra <andrei@fcns.eu>
On 26 September 2012 14:29, Ben Laurie <benl@google.com> wrote:

> On 26 September 2012 13:09, Melvin Carvalho <melvincarvalho@gmail.com>
> wrote:
> >
> >
> > On 26 September 2012 13:59, Ben Laurie <benl@google.com> wrote:
> >>
> >> On 26 September 2012 12:10, Henry Story <henry.story@bblfish.net>
> wrote:
> >> > Answer to the questions and summary at the end.
> >> >
> >> > On 26 Sep 2012, at 12:14, Ben Laurie <benl@google.com> wrote:
> >> >
> >> >> On 26 September 2012 10:56, Henry Story <henry.story@bblfish.net>
> >> >> wrote:
> >> >>>
> >> >>> On 26 Sep 2012, at 11:15, Ben Laurie <benl@google.com> wrote:
> >> >>>
> >> >>>> On 26 September 2012 09:54, Henry Story <henry.story@bblfish.net>
> >> >>>> wrote:
> >> >>>>>
> >> >>>>> On 26 Sep 2012, at 10:42, Ben Laurie <benl@google.com> wrote:
> >> >>>>>>
> >> >>>>>> Once more, I remain unenlightened about the answers to my
> >> >>>>>> fundamental questions.
> >> >>>>>
> >> >>>>> Can we perhaps start back at your fundamental question again? We
> got
> >> >>>>> sidetracked here a bit because of my-profile.eu
> >> >>>>> no working well for you.
> >> >>>>>
> >> >>>>> The last thing I remember you stating is that authenticating with
> >> >>>>> one ID across multiple sites is in your view a horrendous thing.
> Is that the
> >> >>>>> fundamental problem?
> >> >>>>
> >> >>>> One of them. And not just my view - the view of many. Here's a
> >> >>>> presentation from a colleague that illustrates our thinking on the
> >> >>>> use
> >> >>>> of client certs for authn:
> >> >>>> http://tools.ietf.org/agenda/81/slides/tls-1.pdf.
> >> >
> >> > Ok so this paper is about "Origin-Bound" Certificates. The problem is
> >> > that they are trying to use certificates the way one uses   cookies. A
> >> > hidden mechanism for a server to identify you securely from on
> session to
> >> > the next. And this is not what we are interested in here, since we are
> >> > interested in cross site identity ( selectable by the user in a way
> which he
> >> > is at all time in control of)
> >> >
> >> >>>>
> >> >>>> In case its not obvious, the problem is that its a massive privacy
> >> >>>> invasion.
> >> >>>
> >> >>> Well as I pointed out, it is not a problem if the user controls and
> is
> >> >>> aware of the identity he is revealing on each site. This is a
> simple User
> >> >>> Interface issue which Aza Raskin showed in 2009 how to solve
> >> >>>
> >> >>>
> >> >>>
> https://blogs.oracle.com/bblfish/entry/identity_in_the_browser_firefox
> >> >>
> >> >> Manually choosing one of hundreds of certs sure sounds like a problem
> >> >> to me!
> >> >
> >> > You would never have more than a handful to choose from, and your
> >> > certificates could
> >> > default to being the last one you used for a site.
> >> >
> >> > The reason you are thinking you need 100s of certificates is probably
> >> > because you think
> >> > you need a certificate per site. This misunderstanding is deeply
> >> > ingrained it seems.
> >>
> >> It is not a misunderstanding, it is a requirement! You think I'm OK
> >> with all sites being able to link me up: I'm not!
> >
> >
> > Ben, doesnt google do this already.  I see "SIgn in with Google" button
> > across the web.  I presume that will share an identity across different
> > domains, much like OpenID or Facebook Connect.
>
> It isn't _like_ OpenID, it _is_ OpenID. And yes, Google does do it
> already. I'm not a fan, and it seems neither is most of the world,
> which is kinda my point.
>
> > Similarly the ubiquitous google +1 buttons have similar privacy issues.
>
> Many things have privacy issues, but google +1 buttons are not for login.
>
> > Is one of the issues, as mentioned in the IETF document that the UI pops
> up
> > BEFORE you have had a chance to view content?
>
> Not sure what you mean here. Certainly sites like to have some control
> over the user experience, and this is another issue with client certs
> - you select them before the page loads. Is that what you meant?
>

Thanks for the clarification, yes that's what I meant.  OK, that makes
sense.


>
> >> >>> and which for which there is a bug open in pretty much every
> browser,
> >> >>> e.g.: Chrome
> >> >>>
> >> >>>   http://code.google.com/p/chromium/issues/detail?id=29784
> >> >>>
> >> >>> So does the above paper take into account that the user could be
> aware
> >> >>> of the identity
> >> >>> he is using, and control it?
> >> >>
> >> >> The above paper uses a certificate per site. Identity is controlled
> in
> >> >> Chrome by using the "Users" feature.
> >> >
> >> > Ah yes, you have origin bound certificates. That has a use, but not
> one
> >> > if you wish
> >> > to link information up between web sites.
> >>
> >> Well, now we get to the core: you want to allow linking. Fine, in its
> >> place. But this is not a good property for a general-purpose login
> >> system.
> >>
> >> So, if you want me to replace login with WebID, then you need to have
> >> a good story around _not_ linking, also.
> >>
> >> >>> Btw. if you consult the spec you'll see that all a user needs to
> >> >>> publish to the world
> >> >>> is his public key
> >> >>>
> >> >>>
> >> >>>
> http://www.w3.org/2005/Incubator/webid/spec/#publishing-the-webid-profile-document
> >> >>
> >> >> Publishing all your public keys would defeat the purpose of per-site
> >> >> certificates - unless you publish each on a different page.
> >> >
> >> > We here in the WebID group are not speaking about per-site
> certificates.
> >> > Our core model is one where one certificate can be used on many
> sites. Per
> >> > site certificates give you not much more than a cookie. That is an
> >> > orthoganal issue.
> >> >
> >> >>
> >> >>> All the rest can be access controlled.
> >> >>>
> >> >>>>
> >> >>>> Next:
> >> >>>>
> >> >>>> 1. Usability in the browser is only part of the problem. But
> >> >>>> nevertheless it remains a problem.
> >> >>>
> >> >>> A problem that browser manufacturers can fix, pretty easily, and
> which
> >> >>> is even going to be a legal requirement for them to do, as was
> >> >>> explained
> >> >>> at the IETF summit in Paris earlier this year.
> >> >>
> >> >> Oh really? Got a link?
> >> >
> >> > This was organised by the IETF SAAG ( Security Area Advisory Group )
> >> > http://www.ietf.org/mail-archive/web/saag/current/msg03614.html
> >> >
> >> > But you should not be surprised. Think of it: the Europeans take
> privacy
> >> > seriously.
> >> > Browsers can make people aware of the privacy on each site. The law
> >> > requires that
> >> > if possible things be done. It is possible. QED: do it.
> >>
> >> I am a European, and I do take privacy seriously. Perhaps you'd like
> >> to explain why privacy should not apply to WebID?
> >>
> >> BTW, this law is in effect now and it does not require anything of
> >> browsers.
> >>
> >> >>>> 2. If am all signed up to WebID and I get a new device, how do I
> get
> >> >>>> it signed up? I know your stock response is "you just go through
> the
> >> >>>> flow again" - once for every site I'm registered with - using what
> to
> >> >>>> identify myself? Bear in mind that there has to be a per-site
> >> >>>> certificate.
> >> >>>
> >> >>> Ah! Here we get at the crux of the misunderstanding!!!
> >> >>>
> >> >>> There does not have to be a per site certificate when WebID is used.
> >> >>> This is what Linked Data permits us to avoid. This is why WebID is
> so
> >> >>> useful. It is why X509 failed as client certificates. Indeed if all
> you can
> >> >>> use a client certificate for is your own web site then it has very
> little
> >> >>> use - you might as well use a cookie, or a password. But if you can
> then
> >> >>> connect to other sites, and login in one click, then things are
> different -
> >> >>> completely different.
> >> >>
> >> >> If your answer is that WebID relies on me giving up on not being
> >> >> linkable across all sites, then we may as well stop talking now -
> >> >> WebID is useless.
> >> >
> >> > It does not rely on you giving up not being linkable across all sites.
> >> > It allows you to link when you want to. (see the browser issues above)
> >> > There is a world of difference between those positions.
> >> >
> >> >> But even for a single certificate you have not answered the question.
> >> >
> >> > see answer 5 below for the detailed answer.
> >> >
> >> >>
> >> >>>> 3. Related: if I lose all my devices, how do I recover?
> >> >>>
> >> >>> If you still have your server you go there and remove all public
> keys.
> >> >>> If you are using a service provider at a university you go and see
> him and
> >> >>> tell him to remove all your keys. If you are at Google, then you
> get hold of
> >> >>> the hotline? How do you do it now?
> >> >>
> >> >> What? Users have to have servers? This is clearly a non-starter.
> >> >
> >> > No they don't have to have servers, and I never said so.
> >> >
> >> > Notice the "if" in "If you still have your server" ?
> >> > And the "If" in "If you are using a service provider" ?
> >> > And the "If" in "if you are at Google" ?
> >> >
> >> > Unless you think that those all are the same - ie you work at Google -
> >> > then you will see that this is a choice left up to the end user. Does
> it
> >> > bother you that I could have my own server?
> >>
> >> If your solution requires Google to run a call centre, then Google
> >> will not use it.
> >>
> >> >> Now, you login using your password, just as you have always done.
> This
> >> >> is one reason passwords won't go away easily - they're only tied to
> >> >> me, not my devices.
> >> >
> >> > We never said that you need to get rid of passwords. It is just that
> >> > with that certificate you no longer need to login with a password to
> any
> >> > other site. And probably won't need to login with a password to your
> own
> >> > site other than in a case of disaster.
> >>
> >> So the usability problem here is that a password I do not use
> >> regularly is a password I cannot remember.
> >>
> >> > There is also the possibility of having one time passwords, which I
> >> > think Google is working on too. And standards like OATH
> >> >
> >> >
> http://www.crypto-stick.com/2012/OATH-One-Time-Passwords-Allow-Login-to-Gmail-Dropbox-AWS
> >>
> >> I believe we actually use OATH. One time passwords are already rolled
> out,
> >> btw.
> >>
> >> >>>> 4. How do I revoke access when my laptop is stolen?
> >> >>>
> >> >>> You go to the server and remove the public key from your profile.
> >> >>
> >> >> How do I log in to the server?
> >> >
> >> > You use a one time password generated perhaps with
> >> >
> >> >
> http://www.crypto-stick.com/2012/OATH-One-Time-Passwords-Allow-Login-to-Gmail-Dropbox-AWS
> >> > or a very long password you use very rarely.
> >>
> >> See above.
> >>
> >> >>> Or you ask your admin to do that. Or if you have your own server at
> >> >>> home, can't remember anything, then you unplug it.
> >> >>>
> >> >>>>
> >> >>>> 5. How do I migrate my existing username/password accounts to
> WebID?
> >> >>>
> >> >>> There is a technical answer and UI answer for that.
> >> >>>
> >> >>> Let me start with the user's point of view. Here is how that would
> >> >>> look if we were to
> >> >>> imagine a user (me) using Google+.
> >> >>>
> >> >>> One day I go to google plus on my desktop browser and Google Plus
> >> >>> entices me to
> >> >>> "Use WebID and login securely across the web"
> >> >>> I click on that banner, and pronto, a certificate is created and
> >> >>> transferred to
> >> >>> my browser. (ok perhaps you add an intermediate page with helpful
> >> >>> explanations
> >> >>> and cool demos)
> >> >>>
> >> >>> Next I am walking down the street with my Android. Google+ is clever
> >> >>> enough to notice that my android does not have a certificate - it
> does a TLS
> >> >>> request for a client certificate, but receives none - and so asks me
> >> >>>  "Hi Henry, get a WebID certificate for your phone too"
> >> >>> I click the banner and oops I have a certificate in Android.
> >> >>
> >> >> Up to here this mostly makes sense, but...
> >> >>
> >> >>>
> >> >>> Once I have a certificate for a device, I can log into any web site
> >> >>> that supports WebID in one click. I can also determine for any site
> how much
> >> >>> information I wish to give that site about me - using access
> control on
> >> >>> information at my profile. Someting we need to work on still.
> >> >>
> >> >> Once more, this is an unacceptable privacy problem.
> >> >
> >> > Because you keep thinking that the user does not have a choice in
> >> > controlling his identity on the sites he visits. And that is because
> you are
> >> > not a User Interface Expert. But User Interface experts have looked
> at this
> >> > and made it easy to use and control. See
> >> >
> >> >    http://www.azarask.in/blog/post/identity-in-the-browser-firefox/
> >> >
> >> > and the pictures in big
> >> >
> >> >   http://www.flickr.com/photos/azaraskin/4128966575/sizes/l/
> >>
> >> Well, we're back to "how does this work when I have hundreds of
> >> certificates?"
> >>
> >> >
> >> >
> >> >>
> >> >>> So the Technical answer, is that Google+ adds to each profile a
> >> >>> representation that can be read as explained in the spec
> >> >>> http://webid.info/spec/ . It is quite easy to retrofit a normal web
> >> >>> site with this info.
> >> >
> >> >
> >> > To sum up your problem (in my view) is that you think authenticating
> >> > with one linkable id across sites is a privacy problem. You believe
> that
> >> > because you don't allow the possibility of a User Interface that
> makes it
> >> > easy for people to be in control of the identity they user per web
> site. The
> >> > User Interface elements for that have been proposed and would be easy
> to
> >> > implement.
> >>
> >> The easy interface works well only if you are happy with a small
> >> number of identities - i.e. linkability across almost everything.
> >> Also, note that this kind of thing was tried with Microsoft's
> >> InfoCards and also with OpenID. It didn't go so well.
> >>
> >> >
> >> > So I agree with you: if one were not in control of one's identity as
> one
> >> > switches between web sites, then one would have a privacy problem.
> But I
> >> > believe one can be in control of one's identity as one switches
> between web
> >> > sites ( see Aza Raskin's work ).
> >> >
> >> > Given that the question is what would the benefit be of this linked
> >> > authentication?  My short answer is that it allows people to work
> across
> >> > organisations in a distributed way, which would be a major benefit to
> >> > society. For more you can see my talks on http://bblfish.net/ .
> >> >
> >> >
> >> > Henry
> >> >
> >> >
> >> >
> >> >>>
> >> >>> Henry
> >> >>>
> >> >>> Social Web Architect
> >> >>> http://bblfish.net/
> >> >>>
> >> >
> >> > Social Web Architect
> >> > http://bblfish.net/
> >> >
> >>
> >
>
Received on Wednesday, 26 September 2012 12:34:41 UTC

This archive was generated by hypermail 2.3.1 : Sunday, 31 March 2013 14:40:59 UTC