[cryptography] current digital cash / anonymous payment projects?

James A. Donald jamesd at echeque.com
Thu Dec 2 02:32:46 EST 2010

On 2010-12-01 11:18 PM, Ian G wrote:
> On 1/12/10 6:12 AM, travis+ml-rbcryptography at subspacefield.org wrote:
>> Can anyone give me a good rundown of the current anonymous payment
>> systems, technologies and/or algorithms?
> OK, there are some issues here. There is technology, algorithms,
> patents, techniques, protocols, applications, services, business models
> ... all lumped into one general term without care.
> Anonymous payment systems are a bit of a contradiction, internally. What
> you're probably talking about is untraceable payment systems, which
> typically use Chaum or Brands or Wagner algorithms (there are a handful
> of other variants). In this model, the "coin" is stripped of its
> identifying information as it transfers from Ivan to Alice to Bob. When
> Bob deposits the coin to Ivan (issuer) for credit to his account, or for
> rollover to new coins, the chain of traceability is broken.
> Then, there is another variation called nymous payment systems. This
> model is typically done with a client-server public-private key
> arrangement, where the client registers the public key, and signs
> requests (including payments) which are sent to the server. The privacy
> trick with this one is that the issuer doesn't need to know who holds
> the private key; so while everything is traceable, it's also nymous.

For anonymous payments to actually be anonymous, we need both nymity and 

Nymity means that anyone can have lots of different and seemingly 
unrelated communication end points, such as, for example, email addresses.

With Pecunix, you can pay anyone who has an email address, with no 
requirement for the recipient to demonstrate a true name known to the 
state - but transfers between one email address and another are traceable.

For anonymity, one has to be able to have cheap and disposable nyms, 
*and* be able to transfer funds between nyms without anyone being able 
to discover that one nym is getting the money from the other nym.

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