Credentials Without Identity

Rich Graves makes some very good points, but he said something I want to
riff on.

(And as a measure of how apologetic some folks are getting about discussing
anything not on Perry's List of Approved Topics, Rich unfortunately labeled
his post "[ID point semi-off-topic]..." In fact, the issue of credentials
and identity is NOT off-topic, not even semi-off-topic. It is central to
the themes of our list. I urge all to read Chaum's seminal work on
"credentials without identity.")

At 1:05 AM 11/5/95, Rich Graves wrote:

>Proving legal residency requires a combination of two documents, one each
>from specified lists. Most commonly a driver's license, green card (which
>is actually pink), or birth certificate from list A, and a social
>security card from list B.
>
>Chris Hibbert's SSN FAQ talks a little bit about how this works, and why
>it's a Good Thing. Basically, for privacy and security reasons, it is a
>very good idea to separate the issues of identity and authorization.
>
>I don't care how securely you can authenticate who I am -- by PGP, retinal
>scan, whatever. I do not want a single digitizable token to be the key to
>my identity. Even if that identity cannot be forged (and everything can be
>forged), it can be used to track me, by the government, by the Direct
>Marketing Association, by the private investigators of certain wacky
....

Chris's (or Chris') points are admirable, but getting more and more
irrelevant by the day. The notion of unlinking identity and authorization
by separate pieces of identification is another form of "security through
obscurity."

The two forms of credentials can be linked in data bases. Just because one
piece of ID has citizenship or voting status and another has other stuff is
meaningless, provided the ID forms can be linked. As they can, in multiple
ways.

The credit tracking agencies can do this trivially, with names, social
security numbers, driver's license numbers, addresses, phone numbers, etc.
All are pointers into the cloud of numbers that constitutes one's dossier.

Happily, Chaum's work on "credentials without identity," based essentially
on the kind of "blinding" used in digital cash (with some differences, of
course), allows for one to display a credential showing one is old enough
to enter a bar or library (in 2005), without revealing a name (which is
just another credential).

--Tim May

Views here are not the views of my Internet Service Provider or Government.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May              | Crypto Anarchy: encryption, digital money,
tcmay@got.net  408-728-0152 | anonymous networks, digital pseudonyms, zero
Corralitos, CA              | knowledge, reputations, information markets,
Higher Power: 2^756839      | black markets, collapse of governments.
"National borders are just speed bumps on the information superhighway."

Timothy C. May writes:
> (And as a measure of how apologetic some folks are getting about discussing
> anything not on Perry's List of Approved Topics,
[....]
> In fact, the issue of credentials
> and identity is NOT off-topic, not even semi-off-topic. It is central to
> the themes of our list. I urge all to read Chaum's seminal work on
> "credentials without identity.")

I've repeatedly stated, Tim, that my problem is with junk, not with
stuff on list charter. You can claim anything you like about my
statements, but it won't be true. Any statement to the effect that I'm
against discussion of anonymous credentials is a "big lie" -- an
attempt to distort what I have said by being sufficiently outrageous.

Repeating, I am troubled by people posting stuff about whether
roadways should be privatized -- I am perfectly happy with discussion
of Chaumian anonymous credentials. My problem is with people who think
this is Libernet, or Waconet, or Fosternet, or IBM MicroKernel net, or
Internet Investing Net, or what have you. I also find the beating of
dead horses unfortunate, but I never complain about it since its
usually technically on topic.

Now, Tim, if you feel people should be able to post their questions
about system administration of Unix boxes here, as in fact happened
only last week, please speak up.

Perry

On Sat, 4 Nov 1995, Timothy C. May wrote:

> (And as a measure of how apologetic some folks are getting about discussing
> anything not on Perry's List of Approved Topics, Rich unfortunately labeled
> his post "[ID point semi-off-topic]..." In fact, the issue of credentials
> and identity is NOT off-topic, not even semi-off-topic. It is central to
> the themes of our list. I urge all to read Chaum's seminal work on
> "credentials without identity.")

Thanks for the newbie correction.

In case anyone else is new to this, I couldn't find that paper, but Chaum's
ideas and references are at http://www.digicash.com/publish/sciam.html

> >Proving legal residency requires a combination of two documents, one each
> >from specified lists. Most commonly a driver's license, green card (which
> >is actually pink), or birth certificate from list A, and a social
> >security card from list B.
> >
> >Chris Hibbert's SSN FAQ talks a little bit about how this works, and why
> >it's a Good Thing. Basically, for privacy and security reasons, it is a
> >very good idea to separate the issues of identity and authorization.
> >
> >I don't care how securely you can authenticate who I am -- by PGP, retinal
> >scan, whatever. I do not want a single digitizable token to be the key to
> >my identity. Even if that identity cannot be forged (and everything can be
> >forged), it can be used to track me, by the government, by the Direct
> >Marketing Association, by the private investigators of certain wacky
> ....
> 
> Rich's (or Chris') points are admirable, but getting more and more
> irrelevant by the day. The notion of unlinking identity and authorization
> by separate pieces of identification is another form of "security through
> obscurity."

True. But until digital technology becomes ubiquitous, we're stuck with
it, and it does help. I see no analog, well, analog to credential 
technology. It absolutely requires machines that can generate and handle 
large random numbers. Right?

My point was, even people who should know better, like the managers and
clients of FBOI (fboi@netcom.com), are relying on security through appeal
to irrelevant crypto authority, which is even worse. Using your primary
pgp key as a traceable link to your credit card number or bank account can
be just as bad as publishing your credit card number. 
 
> Happily, Chaum's work on "credentials without identity," based essentially
> on the kind of "blinding" used in digital cash (with some differences, of
> course), allows for one to display a credential showing one is old enough
> to enter a bar or library (in 2005), without revealing a name (which is
> just another credential).

I haven't yet fully digested this concept, but don't you get into a bit of
a chicken-and-egg problem when you start applying this to things like
proof of age and citizenship? Until you reach a certain age, you're not
going to remember your passphrase. I still think there's a role for
private keys held by some authority (I realize that's not a popular word). 

I'd guess this would be addressed by a "secret sharer"/secsplit kind of
thing, where your parents hold a combination of keys that together can
represent your secret key until you're old enough to change it yourself. 
Still I'd worry about what kind of information was gathered about me in my
youth, and how that might be carried over into maturity. 

-rich

On Sat, 4 Nov 1995, Timothy C. May wrote:

> The credit tracking agencies can do this trivially, with names, social
> security numbers, driver's license numbers, addresses, phone numbers, etc.
> All are pointers into the cloud of numbers that constitutes one's dossier.

Ah, the Swedish way is so much more convenient. Directly after birth you
get a tag around your arm, with a number that is later changed to an
entry into several databases, including 'Birth Registry' and you get
your Person Number for life, in the format YYMMDD-abcd, which is
unique (at least in Sweden). All forthcoming database entries are based
on this number, usually as a first key field. Surprise immigrants get a
preliminary number at the border (other format) and a genuine one if
later accepted. Without a Person Number you would be practically
helpless: no schooling, no drivers licence, no 'social benefits',
no bank account, no job (if your employer intends to do it legally
and cut off taxes). The only marginally possible way to get around
this is to use the Person Number of another person (forging a Swedish
Approved ID is quite a task, though, and it's not very kind to that
other person). Most Government databases are open to the public, so
the credit tracking agencies don't have to work very hard regarding
persons (sometimes a bit more with corporate entities; those can be
registered to fall guys - not hard to find in a jurisdiction with
nice jails and short sentences). 

Now, there are laws against cross-referencing various databases
without the approval of the Data Inspection, which often says no.
But if you do it illegaly, there is very little risk of detection.
It looks like the Approved ID will be a smart-card with a signing
mechanism (probably escrowed), naturally linked to the Person Number,
real soon now, at least before the mythical y.2000 . Links to physical
characteristics (retina?) are not (openly) discussed yet but may
eventually come into play.

I think there's not much to win (and a lot of conveniency to loose)
in trying to hide from this System. A friend of mine, and his wife,
had their baby born at home and hid it from the System for several
years (loosing good money from the Social Security system in that
process - in Sweden all people get many 'benefits'= transferred tax
money, regardless of income) but eventually they registered the child,
of course. It was a mere gesture.

Solution:

1) Don't fight the inevitable, like Don Quixote (sp?) did. The
   trick is to keep one's database entries as unsuspicious as
   possible. Pay politically correct items and services with
   a credit card, but use cash in transfers that the current
   (and possibly a coming, more Orwellian) regime might consider
   to be disloyal. Don't refuse to fill in forms or answer
   questions which are more or less obligatory or that might give
   you some benefits - just lie if necessary to create a normal,
   inconspicuous profile.

2) Prepare for Crypto Anarchy. Create untrackable net aliases for
   future use. Keep informed of all the tricks to bypass coming
   futile attempts to link net pseudonyms to Person Numbers (or
   physical characteristics). Enjoy (and help create and protect)
   the virtual sanctuary with digital mixes and anonymous http
   proxies (and DC-nets or something better eventually).

Mats