[Noisebridge-discuss] Is there an electronic equivalent of cash?

[Rebecca Bellovin]

On Fri, 11 Dec 2009 21:57:55 -0800
Jason Dusek <jason.dusek at gmail.com> wrote:

>   Is there a way to pay anonymously online, either in
>   theory or in practice?
> 

In theory, yes (http://en.wikipedia.org/wiki/Digital_cash).  This was
originally work of David Chaum in the '80s using blind signatures
("Blind signatures for untraceable payments",
http://dsns.csie.nctu.edu.tw/research/crypto/HTML/PDF/C82/199.PDF).
There's also a second paper from 1990 by Chaum, Fiat, and Naor
("Untraceable electronic cash",
http://dsns.csie.nctu.edu.tw/research/crypto/HTML/PDF/C88/319.PDF)
which improves the protocol: the penalty for spending the same
electronic coin twice is having your identity revealed!  Both papers
are pretty readable, and involve pretty much no math.

At some point, Chaum started a company to implement his electronic
cash scheme, but it went bankrupt some time ago.

Rebecca Bellovin