Subject: Re: [apps-discuss] [websec] [kitten] [saag] HTTP authentication: the next generation

From: Ben Laurie <[email-masked]>
Date: Thu, 6 Jan 2011 15:31:51 +0000

On 6 January 2011 01:28, Robert Sayre <[email-masked]> wrote:

> > Peter Saint-Andre <[email-masked]> wrote:
> > 2. In 2007, Robert Sayre put together a few slides on the topic:
> > http://people.mozilla.com/~sayrer/2007/auth.html
>
> These are back on the Web, in case anyone missed them (probably not).
>
> On Sun, Dec 12, 2010 at 5:39 PM, Roy T. Fielding <[email-masked]>
> wrote:
> >
> > Define them all and let's have a bake-off.  It has been 16 years since
> > HTTP auth was taken out of our hands so that the security experts could
> > define something perfect.  Zero progress so far.
>
> I think the IETF might do better to focus on a smaller problem, at
> first. People often use self-signed certificates with HTTP/TLS, even
> though the first thing their websites ask the user to do is type a
> username and password into a form. There are some well-understood ways
> to make this process more secure. Why hasn't the IETF fixed this
> problem? If this smaller problem has no ready solution, then the
> larger issue of authentication on the entire Web seems like a tough
> nut to crack.
>

Two comments (one really being a response to Roy):

1. The IETF has fixed the problem, but no-one is using the fix - perhaps
because it is not clear that it is the fix. I speak of RFC 4279, TLS
pre-shared keys. These could be derived from a hash of the password and the
site name, for example, and thus provide secure mutual authentication
despite password reuse.

2. I have often heard (though I am not aware of hard evidence for this,
nevertheless I find it plausible) that one reason no-one has bothered to
improve HTTP auth is because no-one would use it since site owners want to
control the user experience around signin. It seems to me, therefore, that
HTTP is the wrong layer to fix the problem at - it needs to be pushed down
into HTML or Javascript so that the page can control the look, while
appropriate HTML elements or JS code can deal with the secure exchange of
data.

Of course, this still leaves the issue of trusted path: although we can
provide elements which are safe to use, even when being phished, how does
the user know those elements are actually being used, rather than simulated
so as to get hold of the underlying password?

The answer to this problem is hard, since it brings us back to taking the UI
out of the sites hands.

> It could be that the reasons for this lack of progress are
> nontechnical. Just throwing that out there.
>

If you think UI is nontechnical, then I agree.

Cheers,

Ben.

---

From: David Morris <[email-masked]>
Date: Thu, 6 Jan 2011 08:03:54 -0800 (PST)

> The answer to this problem is hard, since it brings us back to taking the UI

Which is only helpful if you can somehow gaurantee that the user agent 
software hasn't been compromised. Not something I'd bet on...

---

From: Robert Sayre <[email-masked]>
Date: Wed, 5 Jan 2011 20:28:08 -0500

> define something perfect.  Zero progress so far.

Hard to disagree with this assessment.

It's pretty easy to define something better than the current HTTP
authentication mechanisms, but pretty hard to design something more
popular than forms+cookies.

I've looked at this problem a little bit, and I gather the strictly
technical security properties we're looking for are pretty well
understood. Deployment and presentation control are the tough parts.
Presentation control is actually a security trade-off--to get the
control web designers want, you have to present graphics before the
server has been authenticated. Also, I suspect it will be difficult to
deploy a new HTTP mechanism that can withstand replay and DoS attacks,
unless proxy conformance gets a lot better. So, I think those
advocating TLS-only solutions might turn out to win the day, but not
because the security properties on offer are particularly compelling.

-- 

Robert Sayre

"I would have written a shorter letter, but I did not have the time."

---

From: Tim <[email-masked]>
Date: Thu, 6 Jan 2011 08:25:59 -0800

> appropriate HTML elements or JS code can deal with the secure exchange of

Yes, the user experience piece is definitely the biggest adoption
problem for HTTP auth, IMO.  However, I disagree that HTTP is the
wrong layer.  It has already been shown (by myself and others) that
using HTTP authentication and controlling the user experience can
largely be achieved already.  A few tweaks to browser 401 response
behavior (which doesn't require standards changes) and the ability for
servers to force a log out are all that's left to provide to make
this reliable.

As for RFC 4279, I'm not really familiar with it, but I imagine the
mechansims which allow for user experience customization right now
with HTTP auth could easily be extended to any TLS authentication
mechansim.  The only requirement there would be to add some simple
language allowing for this behavior in [1].  That is, allow
XMLHttpRequest objects to hand the credentials they already accept off
to the TLS layer, either for RFC 4279 or for SRP/TLS.  

> The answer to this problem is hard, since it brings us back to taking the UI

Yes, so what I've outlined above and elsewhere is a relatively simple
transition path to allow adoption of better authentication standards
with customizable user interfaces.  But those are problematic by
design.  However, I'd assert that moving web applications off of
cookies to some lower-layer mechanism is going to be a required first
step in order to provide authentication prompts that are part of the
browser, for those who need that security.

tim

1. http://www.w3.org/TR/XMLHttpRequest/

---

From: Ben Laurie <[email-masked]>
Date: Thu, 6 Jan 2011 18:16:15 +0000

> software hasn't been compromised. Not something I'd bet on...

That's rather overstating it. It's perfectly helpful when the UA
software hasn't been compromised, which is a non-zero fraction of the
time.

When the UA s/w has been compromised I'm quite happy to fail to fix
the problem: the right answer to that is to improve the robustness of
the UA.

---

From: Marsh Ray <[email-masked]>
Date: Thu, 06 Jan 2011 13:51:53 -0600

On 01/06/2011 12:35 PM, der Mouse wrote:
>> Look back far enough and you'll find all kinds of "electronic mail"
>> services implementing the full range of peer and end user
>> authentication, and sender-pays models.  There was no spam on those
>> systems, or at least not enough that anyone felt like they needed a
>> word for it.
>
> There was basically no spam on open-Internet SMTP mail either, at the
> time.  Certainly "no spam" by today's standards.
>
>> Guess why we use the one we use today.
>
> At the time, the services you deride weren't providing a significant
> value-add.

I wasn't so much deriding them but saying there were points all over the 
trade-off curve and the market voted with its feet. Unambiguously.

Of course, the marketing creeps followed.

> Today?  They would be.  Perhaps not enough to make up for their costs;
> probably not, in fact, or there'd be businesses arising in that space.

There are plenty. It's a commoditized low-margin business these days. 
But the network infrastructure costs are not nearly the biggest cost 
once you factor in things like end-user support.
E.g. http://www.google.com/search?q=hosted+vpn

It occurred to me last night that one might recreate the good old days 
of the Internet with a VPN which allowed access to the good old folks 
who were on it back then. Sounds a little crass and elitist now that I 
propose it out loud.

But imagine a global authenticated VPN where the only reason you could 
be banned is for spamming? Or one where you had to be at a university CS 
department? Or a whole set of overlapping criteria and you could choose 
what the membership criteria for your own view of the network?

Your own personal Virtual Public Internet.

> As a side note, it's interesting to see how well the early Internet
> designers built; their systems are routinely being stressed several
> orders of magnitude beyond what they were designed for, and are holding
> up remarkably well.

It is amazing, isn't it?

> The postal system did collapse when it started
> suffering from spam; that's why the paper chain mail is actually
> illegal in many jurisdictions - it took down the postal system, once
> upon a time.

Nice.

> The telphone system would collapse if phone spam
> outnumbered real calls by 10, 25, 100 to 1.  (Actually, in a sense they
> already do.  I have a fax line set up, and get dozens of fax spams for
> every real fax.  I've had to start adapting and applying my email spam
> fighting techniques there....)

We get so many unsolicited calls from telemarketers and robot dialers at 
home we don't answer the phone unless we recognize the caller ID. 
Sometimes family calling from roaming cell phones show up as 
'unidentified caller' and we mistakenly don't answer. How much more 
broken can it be?

- Marsh

---

From: der Mouse <[email-masked]>
Date: Thu, 6 Jan 2011 13:35:40 -0500 (EST)

up remarkably well.  The postal system did collapse when it started
upon a time.  The telphone system would collapse if phone spam

/~\ The ASCII				  Mouse
\ / Ribbon Campaign
 X  Against HTML		[email-masked]
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B

---

From: Phillip Hallam-Baker <[email-masked]>
Date: Sat, 8 Jan 2011 11:07:38 -0500

I think that Ben is right that we are solving the wrong problem.

The problem is that users are asked to maintain accounts at literally
HUNDREDS of accounts.

And some cretins, some utter morons, some bog-brained berks think it is
reasonable to tell the user to have a different password for every one!

I can't remember the account names, the password is easy as I only had one
(for non financial) - until those cretins at Gawker screwed up. Now I have
to reset my password at all those places.

We have to solve the federated auth problem and it is really, really easy:

Account Name is the RFC 821/822 email address.

This is what the Web has started to adopt of its own accord as a user
account identifier. It is the only one that people can remember reliably.

Authentication service is resolved via DNS service lookup

i.e. SRV or similar. I can show people how to fix up the issues to do with
use of non-canonical names.

Client authenticates to authentication service using any protocol they both
support.

This is quite simple to implement, just stick a list of supported auth
services in the DNS.

We can re-use all those existing auth protocols that work (SAML would be a
good choice but we don't need to be overly restrictive here.)

HTTP carries a standardized, non-linkable auth token

I have some ideas on how we could modify DIGEST to do this. DIGEST would not
be problematic if the password had 128 bits of ergodicity and we upgraded
the digest function.

The reason for re-using DIGEST here would be to avoid patent encumbrances. I
considered the issue of linkability at great length when writing the
original DIGEST design.

At the moment I am focused on getting the foundation laid. But I will try to
come up with a full proposal before Prague.

I know that you can achieve some of the desired authentication properties
with public keys at the client. The problem is that our current use of
computers has gone way beyond the one-machine-per-person paradigm

On a recent trip to Europe with the family I counted that we had 10
computers with us capable of supporting IP (3 laptops, 3 iPhones, 2
Nintendos, 1 iPad and a kindle).

Cardspace has some really, really great properties but they are totally lost
when you try to make the service accessible from multiple machines by
putting it 'in the cloud'. In fact, other than a manager, I have never found
anyone who reven thinks they know what they mean by 'in the cloud' for
CardSpace. I certainly have never seen an explanation I can understand.

Devices get lost. Devices get stolen. We don't want to encourage that so
there needs to be something more than just a certificate based client auth
scheme.

I think we need some form of centralized (for given account) account
management in the mix so that the user can authorize/deauthorize devices for
use (c.f. Amazon's Kindle account management)

So there are basically two architectural options for using public key. One
is to use it strictly between the client and the auth service and use a
token like approach as discussed above. Another is for the auth service to
issue an assertion of the form 'you can tell its fred by this public key
(amongst others)'.

SAML already has support for both approaches BTW.

On Thu, Jan 6, 2011 at 10:31 AM, Ben Laurie <[email-masked]> wrote:
> _______________________________________________
> saag mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/saag
>
>

-- 
Website: http://hallambaker.com/

---

From: Phillip Hallam-Baker <[email-masked]>
Date: Sat, 8 Jan 2011 11:21:42 -0500

> the problem: the right answer to that is to improve the robustness of

+1

If the UA is stuffed then the user is totally and utterly stuffed anyway.

In particular if the UA is stuffed then a forms based experience is just as
stuffed. If we are going to hypothecate attack models people have to be
willing to apply them to their preferred solution too.

The sensible approach is to work out how to stop the user from being stuffed
e.g.

 * Comodo's free Anti-Virus with Default Deny Protection (TM)
 * Use code signing + trustworthy computing
 * Use a restricted browser

Now I have a lot of ideas on how we can tackle these, but they are not
relevant to this debate.

I do however have a different take on the UI issue.

HTML forms did have an advantage over the pathetic UI that browsers provided
for BASIC and DIGEST (most don't even tell the user which is in use).

But a federated auth scheme supported at the HTTP level could be simpler
still. Instead of the user having to register for each site, they register
once. Instead of the user having to log in to each site they log in once per
session. Instead of the site having to manage lost passwords and forgotten
accounts because the user has hundreds, this problem does not exist.

It is a user interface crisis that is driving this need in my view.

---

From: Blaine Cook <[email-masked]>
Date: Sat, 8 Jan 2011 09:37:00 -0800

Two points:

1. In this entire thread, no-one has mentioned OAuth. Maybe y'all
don't like it, but it's used to authenticate more HTTP requests by
volume and users than everything-except-cookies combined. You may want
to consider the design of OAuth when proceeding with these
discussions, rather than the laundry list of [completely] failed
protocols.

2. With respect to federated auth, especially using email address-like
identifiers, there has been a bevy of (deployed) work in this regard.
The effort is called webfinger, and is worth a look. Instead of DNS,
we use host-meta based HTTP lookups to dereference the identifiers.
Many diaspora and status.net installs are using it today, and there
are several proposals towards building a security & privacy
infrastructure on top of webfinger (webid is one such proposal whose
incorporation of client-side TLS certificates in a browser context
makes me very weary of its potential for success).

b.

On 8 January 2011 08:21, Phillip Hallam-Baker <[email-masked]> wrote:
> apps-discuss mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/apps-discuss
>
>

---

From: Phillip Hallam-Baker <[email-masked]>
Date: Sat, 8 Jan 2011 12:52:45 -0500

OAUTH and Webfinger are both pretty much as good as you can expect to
achieve if you decide at the start that you are not going to modify the
infrastructure.

But that decision limits what you can expect to achieve.

A particular problem with OAuth is that you can only use the identity
providers that are supported by the particular site. So I had to use my
Twitter account to play spymaster. And when Twitter got shirty and started
blocking other players accounts they lost their game account and their
twitter account at the same time.

There are people who think I should get a facebook account just so that I
can use their application. Not happening.

As for WebFinger, it works, but not nearly as well as a clean DNS scheme.
DNS is designed to address this problem, HTTP is not. And solving the
problem with HTTP requires us to have a scheme that involves DNS + HTTP +
SSL + PKIX which is rather a lot of moving parts and to make matters work
some those parts are not just moving, they are changing.

I think it is a very good idea to look at WebFinger and OAuth and see how to
realize these approaches direct in the infrastructure. But they should be
seen as starting points, not ends.

---

From: Ben Laurie <[email-masked]>
Date: Sun, 9 Jan 2011 13:44:12 +0000

On 9 January 2011 01:29, Blaine Cook <[email-masked]> wrote:
> On 8 January 2011 11:49, Zed A. Shaw <[email-masked]> wrote:
>> On Sat, Jan 08, 2011 at 09:37:00AM -0800, Blaine Cook wrote:
>> I don't normally respond, just being a lurker, but this statement is
>> competely wrong Blaine.  OAuth may be used for more requests, but not
>> more sites.  It's used on a tiny number of sites, with OpenID being used
>> on way many more, and even then, not nowhere near the number of websites
>> that form based authentication and browser authentication methods.
>>
>> Don't equate twitter having a ton of traffic to OAuth being some kind of
>> raving success, and sure as hell don't evaluate the technical merits of
>> something by its popularity.
>
> Agreed - though, facebook is also using oauth-based (not 1.0, but
> essentially the same approach) logins, and there are a number of other
> sites that do provide oauth-based login infrastructure.
>
> Moreover, the nudge towards oauth is intended with the movement
> towards a new auth infrastructure in mind. We'd need some kind of
> discovery / negotiation mechanism on top to make it not the
> one-or-two-companies-own-the-web play that login-over-oauth is now.
> (c.f. OpenID Connect).
>
> b.
>
>> While I agree that TLS client side isn't going to work, none of the
>> proposed authentication methods will work without a change to browsers
>> to support a way for two websites to establish a session in the browser.
>> If that feature existed you would cut down on a lot of the complexity of
>> things like OpenID and OAuth.
>
> Again, agreed. ;-)
>
> for the record, I don't think that OAuth itself is a suitable
> replacement for HTTP authorisation, but wanted to stir the pot,
> especially away from overwrought technical solutions that don't
> actually solve anyone's needs.

Towards ones that are ripe for phishing and have no privacy
protections? I don't believe that's a good direction.

---

From: Marsh Ray <[email-masked]>
Date: Sat, 08 Jan 2011 15:32:59 -0600

> I think that Ben is right that we are solving the wrong problem.

I think Ben is nearly always right. :-)

But let me toss out a different perspective. I'll try carefully and hope 
that this doesn't come across as trolling, but it is a bit contrarian 
(hopefully in a good way).

> reasonable to tell the user to have a different password for every one!

Such users have asked to do business with hundreds of entities, so at 
least something is working right.

The user is free to use the same password everywhere (more convenient), 
or use a different password at every site (more secure). Many users like 
to set up "domains of password re-use" among several like-sites. The 
user is free to decide the point on the trade-off that works for them.

I use a different password for everything. I write them down on blank 
business cards and keep them physically secure. I have taught some small 
children to use this scheme and they have no trouble with it. Most web 
browsers and sites remember the passwords anyway so the paper is really 
just backup.

> I can't remember the account names, the password is easy as I only had
> one (for non financial) - until those cretins at Gawker screwed up. Now
> I have to reset my password at all those places.

So you had decided on a coarse-grained scheme: financial and 
non-financial. Seems reasonable on the surface.

Say you have a dozen sites across which you share a password. These 
sites are really secure - let's estimate the probability that each one 
will be breached or compromised or you will accidentally login 
unencrypted from a public internet location is only 1 in 10 per year. 
Hey a 90% success rate isn't bad, right?

But the probability that they will all succeed is 0.9^12 = 28% over a 
year. Expect to be changing that password every few months.

In the case of "HUNDREDS of accounts", 0.9^200 = 0.000000001. Well, 
those of the sort of odds you're supposed to serve the attacker, not 
yourself.

> We have to solve the federated auth problem and it is really, really easy:

No, it borders on the impossible.

>     This is what the Web has started to adopt of its own accord as a
>     user account identifier. It is the only one that people can remember
>     reliably.

Which is why everyone just has one email address? Come on, most people 
have several. And often they do so for a reason, it's not just that 
people get new ISPs or switch for new features all the time. I train my 
kids to lie about their names and ages when they do stuff online. They 
don't have emails.

You don't have a personal email and a work email at least?

>     i.e. SRV or similar. I can show people how to fix up the issues to
>     do with use of non-canonical names.

[skipping a bunch of technical stuff]

> I know that you can achieve some of the desired authentication
> properties with public keys at the client. The problem is that our
> current use of computers has gone way beyond the one-machine-per-person
> paradigm

> Nintendos, 1 iPad and a kindle).

It was only a brief period in the history of computing that might have 
ever been true anyway.
Before networks "user identity" hardly mattered. Immediately after 
networks, we got heterogeneous networks. As soon as heterogeneous 
networks arrived, we got single sign-on.

I think the deeper problem today is that most people looking at the 
issue are coming from the service provider side. Their job is made 
greatly simpler if they can assume 1 user = 1 person = 1 email etc. So 
they make this assumption as much as they can get away with it.

But the reality is that people don't work that way. Historically, people 
have had multiple identities and they presented themselves differently 
to different parties. This is intentional and it's not duplicitous, its 
part of normal social interaction.

When you discuss business matters at work you give out a business card 
with a business phone number and address on it. When you meet people at 
church or school, you give people your home phone. Your home phone and 
address were the ones printed in the directory.

So the fact that "a person" has more than one "device" is not the big 
problem (that's actually sometimes a desperate solution from the 
perspective of the user). The problem for the service provider is that 
they don't want to give up the simplifying assumption (and the 
behavioral tracking it enables) that a real person represents an atomic 
unit of identity.

Aside from the brittleness of their security, this is one reason why 
centralized identity, top-down federated authentication and 
single-sign-on schemes are not a good plan for the web. They don't 
accurately model the problem domain.

These schemes originated for use in corporate and university settings 
which, at the end of the day, have all of the protected resources owned 
by a single party. The universal ritual for everyone's first day at a 
new job is the granting of a new username, password, and email identity 
for use in that specific context. So single sign-on was designed so that 
one person could be granted access to, say, the file server, email, 
printer, and maybe the phone system, all within the restricted context 
of their "employee-ness" at one specific company. Even though multiple 
systems are involved, it's still fundamentally a one-to-one relationship 
between two identities, the person-as-employee and the company-as-employer.

This doesn't map to the web with multiple persons each needing to 
control the mapping of their own multiple identities to multiple 
corporations. I don't want to pull out my US State Department-issued 
passport in order to leave a comment on some random blog or log into an 
online game. I don't want to use any of my gmail addresses for that either.

Bad things happen when you force-fit the wrong model on to the design. 
Security and privacy are always the first to go. (Somewhere I saw the 
other day somebody seriously proposing using Facebook as a centralized 
identity authority.) More subtly, people find the system harder to use, 
and overall they just don't like it or trust it as much. People won't 
use it, or they'll use it and not like it, or they won't use it as much, 
or they'll figure out a way to defeat it.

> Cardspace has some really, really great properties but they are totally
> lost when you try to make the service accessible from multiple machines
> by putting it 'in the cloud'. In fact, other than a manager, I have
> never found anyone who reven thinks they know what they mean by 'in the
> cloud' for CardSpace. I certainly have never seen an explanation I can
> understand.

Cloud is largely an experiment in making unwarranted assumptions about 
identity in the other direction: between the corporation and their devices.

> Devices get lost. Devices get stolen.

My impression is that lost and stolen devices are significant, but 
they're by far not the biggest security issue on the web.

> We don't want to encourage that so
> there needs to be something more than just a certificate based client
> auth scheme.
>
> management in the mix so that the user can authorize/deauthorize devices
> for use (c.f. Amazon's Kindle account management)

You're not going to create everybody's favorite web authentication 
infrastructure if it has the goal of controlling people use of their own 
devices.

> So there are basically two architectural options for using public key.
> One is to use it strictly between the client and the auth service and
> use a token like approach as discussed above. Another is for the auth
> service to issue an assertion of the form 'you can tell its fred by this
> public key (amongst others)'.

Forget the wants of corporations and websites, they exist only because 
of their customers and users who outnumber them a millionfold. Forget 
mechanisms for now, those are simple engineering once the problem is 
stated correctly.

What do people want to do?

What would they want to do if they knew to ask for it?

How can we help them do it in the most secure way possible?

How can we give people the tools to manage their own identities and make 
their own security-convenience trade-offs in the most informed way?

Regards,

- Marsh

---

From: Blaine Cook <[email-masked]>
Date: Sat, 8 Jan 2011 17:29:29 -0800

b.

Again, agreed. ;-)

b.

---

From: Blaine Cook <[email-masked]>
Date: Sun, 9 Jan 2011 08:40:54 -0800

> protections? I don't believe that's a good direction.

*shrug* If the alternative is Facebook handling everyone's logins, it
can't get much worse, can it?

b.

---

From: Theodore Tso <[email-masked]>
Date: Thu, 13 Jan 2011 13:27:10 -0500

On Jan 8, 2011, at 11:07 AM, Phillip Hallam-Baker wrote:

> The problem is that users are asked to maintain accounts at literally HUNDREDS of accounts. 
> 
> And some cretins, some utter morons, some bog-brained berks think it is reasonable to tell the user to have a different password for every one!
> 
> I can't remember the account names, the password is easy as I only had one (for non financial) - until those cretins at Gawker screwed up. Now I have to reset my password at all those places.

The fact that web sites, like Gawker, will screw up, is why you need to maintain different passwords at every single one.  And at least Gawker admitted that they screwed up, and told everyone to change their passwords once this came out.  Many large corporations would have tried to stonewall and claim their security is perfect or at least not publicize the security breach to their users.

Personally, I think the horse left the barn a long, long time ago, and this is not a problem we can fix today.  What I use for my non-financial accounts is the LastPass plugin, which scans HTML form pages looking for username/password form fields, and if it finds them, looks up the username/password in a database which is stored in the cloud in an encrypted fashion, and populates them into HTML form.  It also will automatically generate nice, long, random passwords for every site when you change your password, and allows you easily use long, hard-to-memorize (and thus secure) passwords that are different for every single web site.

The only reason why I don't use it for my financial web sites is because it's a closed source browser plugin, so I can't audit it to make sure it's not stashing away passwords and publishing them to the manufacturer via some covert channel.  But if they want to steal my Financial Times and Economists logins, hey, they can be my guest.

It may be ugly that we're dealing with this at the HTML/presentation battle, but any other solution will take years to roll out, and the issues of trust and liability which to date have doomed any large-scale PKI rollout are going to bite us here.   And in a federated scheme, the question of which federated entities a user should trust to potentially give access to *all* of their web sites is still at best a research problem.  So at least for web security, maybe the best we can do is to make things easier for the browser or browser plugins to manage different accounts at hundreds of different web sites.   This may ultimately be an easier, and be a much more easily deployable, solution than some kind of federated authentication proposal.

-- Ted