Ideal digital cash system?

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On page 123 of Applied Cryptography Bruce Schneier cites the work of
two cryptographers and the digital cash system they invented that
satisfies all six properties he listed on the same page.  In his words:

The authors consider this the first ideal untraceable electronic cash
system.

The reference [674] is:

T. Oamoto and K. Ohta, Universal Electronic Cash
Advances in Cryptology--CRYPTO '91 Proceedings
Berlin: Springer-Verlag 1992 pp. 324-337

Is anyone here familiar with this work?  Has anyone tried to implement
this protocol in some manner?

Also how would I go about obtaining the text of this work either in
written form or online?


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Johnathan Corgan       "Violence is the last refuge of the incompetent"
jcorgan@netcom.com                       -Isaac Asimov
PGP Public Key:        http://www-swiss.ai.mit.edu/~bal/pks-toplev.html
Or send email to:      pgp-public-keys@pgp.ai.mit.edu Subj: GET jcorgan
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Johnathan Corgan <jcorgan@netcom.com> writes:

>The authors consider this the first ideal untraceable electronic cash
>system.

>T. Oamoto and K. Ohta, Universal Electronic Cash
>Advances in Cryptology--CRYPTO '91 Proceedings
>Berlin: Springer-Verlag 1992 pp. 324-337

(This should be Okamoto & Ohta.)

This paper is not available electronically as far as I know.  The crypto
proceedings can be found in good university libraries.

I believe the Okamoto scheme has the problem that payments by a person
are all linkable.  Basically when you open an account with the bank you
get a "license" number B which you keep for all the time (and which the
bank doesn't know).  But every time you spend you have to send B.  So all
of the payments from a person will use the same B.

True, this doesn't reveal his identity, but it allows a given pseudonym's
spending patterns to be recorded and studied, which may be almost as bad.

Okamoto forgot unlinkability in his laundry list of ideal cash
characteristics.

Hal