A 'Funky A.T.M.' Lets You Pay for Purchases Made Online

[Tim May]

On Thursday, July 24, 2003, at 07:12 PM, Steve Furlong wrote:

> On Thursday 24 July 2003 15:50, Tim May wrote:
>
>> In fact, "digicash" strongly suggests David Chaum's "Digicash,"
>
> That assumes the reader or listener has heard of Digicash, or of Chaum.
> Not an assumption I'd be comfortable making.

Agreed, making the assumption that readers here have heard of Chaum or 
understand the basic idea of blinded transactions (or dining 
cryptographers, or oblivious transfer, or any of the other building 
blocks) is no longer warranted. I expect many of the persyns of 
peircing now spewing on the list are, like, thinking "that's, like, 
_so_ nineties."

As for thinking very general readers or listeners, those not even on 
the list, are capable of understanding Chaum or Digicash, that's a 
fool's errand. The average nontechnical person knows nothing about how 
crypto works, and attempting to explain a DC-Net or a blinded transfer 
is no more useful to them than just telling them the currency is based 
on "magic beans."

The point is not that laymen need to understand Digicash, but that 
calling things like ATM cards and Visa cards "digicash" does a 
disservice to the important ideas of why Chaum's and Brands' and 
similar systems worked.

Hey, maybe it's actually the case that some of the people here who are 
referring to electronic debit cards as "digicash" just don't have a 
clue about what blinding is and why it makes for truly untraceable 
tokens.


> I tend to use "electronic money" when discussing coin- or account-based
> systems, anonymous or not, with the unwashed masses. It conveys the
> meaning well enough to serve as an opening wedge to a better
> description, and it's general enough that it shouldn't offend the
> sensibilities of those few people who do understand the subject in
> depth. And it hasn't been gobbled up by any company, so far as I know.

I stopped any efforts to explain the true importance of 
electronic/digital money/cash a long time ago. A waste of time. Not too 
surprising, as getting even the basic idea requires some passing 
familiarity with things like how RSA works. When I read Chaum's 1985 
CACM paper I already knew about RSA and "hard" directions for problems 
(trapdoor functions), and yet I still had to read and reread the paper 
and draw little pictures for myself.

Thinking someone can absorb the gist via a purely verbal description is 
just not plausible. I have seen David Chaum attempt to do this with an 
audience of computer professionals....my impression from the later 
questions from the audience is that his explanation simply didn't get 
them over the "hump" to the stage of realizing the key concept. No more 
so than popularizations of relativity actually ever got the masses to 
understand relativity.

There is much that could be said about whether this difficulty is why 
we don't have untraceable, Chaum-style forms of money (I don't think 
this is the reason). Regardless, wishing won't make it so, and so 
wishing that people would "grok" the importance of blinding without 
having spent at least a few hours brushing up on RSA and exponentiation 
and all that and then following an explanation very, very 
closely....well, wishing won't make it so.

So it's best to ignore the "unwashed masses" and their inability to 
understand untraceable money.

More troubling is that so many _here_ don't seem to "get it."

--Tim May