work at

Before you write asking for a comparison, consider these 2 points: I haven't worked on digital cash systems for a while, as I've been concentrating on the identity solutions developed at (as found in their Assurance process). Secondly, there are thousands of digital cash systems out there, and very few of them learn from each other or from the frameworks like FC7.

DM - Digital Money

Another startup, no code: Digital Money seems to be oriented towards non-robust monies such as LETS, bonus systems, etc.

DMT Digital Bearer Certificates

The DMT project claims to use a Java client to manage your DMT Digital Bearer Certificates. By repute, there is no special formula behind these certificates, so they technically sit alongside the WebFunds Big Random Numbers (BRN) token money method.

Intertrader's architecture - a comparison


Both Ricardo and Intertrader terminology are contrasted below equivalents described.

Here is the quick summary:

Ricardo Intertrader
application (WebFunds / Teller) Wallet / CashBox
value manager * instrument
contract(instrument, item) currency

* WebFunds' Value Manager used to be called Wallet, we deprecated that term so as to remove the clash between our usage and that of other projects.


An Application is a programme that does something. For example,

Side Ricardo Intertrader
Client - downloadable user applications WebFunds can hold different Value Managers, and can use the payment technologies within in a sensible fashion. the Wallet can hold different Instruments, each of which manages a particular payment technology. It can integrate with the browser via a proxy in order to seamlessly enable web retail activities.
Server - payments facilitation for retail merchants, extends from client side. Teller is an early version that can receive requests to deposit incoming payments and requests to write outgoing payments. It only works with one Value Manager, being the SOXWallet. CashBox works with many Instruments to take payins (only) from different technologies.

WebFunds Value Manager == Intertrader Instrument

A WebFunds Value Manager or an Intertrader Instrument is a module offering payments of a particular type and technology. E.g., SOXWallet can do SOX payments and deposits, and a Mondex Instrument can handle the Mondex cash cards.

WebFunds Value Manager

There is one other Value Manager for WebFunds: a trading value manager. This is (in the Java) an extension of the SOX Value Manager.

Each WebFunds Value Manager conforms to the interface located in webfunds/client/ In the case of the SOXWallet, the module itself is at webfunds/client/sox/

SOXWallet will change to insert a GUI-free value manager (and internal interface, see webfunds/sox/value). Then, the original SOXWallet will add the GUI stuff to the new GUI-free Value Manager. This is work is for non-GUI exporters working with SOX (merchant applications like Teller and CashBox).

Intertrader Instruments

For Intertrader, their Instrument list within the Intertrader Wallet (client application) and the Cashbox (payments facilitator) includes:


SWAPEROO was am academic exercise to write a highly flexible client application to manage value. It has a lot of high level documentation, but the code never got out of technology demonstrator phase.

Their terminology uses Instrument as we would use Contract or Value Manager. To them, a Wallet is what we would call WebFunds, an application you can plug multiple "instruments" into, each handling different payment classes or technologies.

I'm not sure on the precise difference; in this, it seems that the Instrument is similar to the use by Intertrader.

Latest status is that IBUC were digging out the code. Unknown licence. If they ever get it working, it will be worth looking at to see how they've done things.

It would be nice to write papers like their's. Check out the project doco: Digital Wallets Project Home Page and Javadoc and Original Paper for 3rd USENIX Workshop on Electronic Commerce, November 1998.

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