Digital cash issuess...

[Eric Hughes]

>As a consequence, our
>cash system is much more efficient in both computation and
>communication complexity than previously proposed systems."

I take this with a grain of salt; see below.

>In our opinion, the most interesting of
>these is that the entire cash system (including all the extensions)
>can be incorporated straightforwardly in a setting based on wallets
>with observers, 

I am not surprised that they find this interesting; David Chaum has
patented all the observer protocols.

Having read these protocols in the original, I can say this is not
much of an advantage.  The observer protocols are tremendously
expensive computationally.  Anything you build on top of it won't be
any faster.

Eric