[118077] in Cypherpunks
ecash means anonymous & untraceable (Re: Will this replace banking?)
daemon@ATHENA.MIT.EDU (Adam Back)
Sun Sep 19 06:37:20 1999
Date: Sun, 19 Sep 1999 11:18:38 +0100
Message-Id: <199909191018.LAA10969@server.cypherspace.org>
From: Adam Back <adam@cypherspace.org>
To: rah@shipwright.com
Cc: cypherpunks@cyberpass.net
Cc: dbs@philodox.com
In-reply-to: <v04210171b409981275a2@[204.167.101.56]> (message from Robert
Hettinga on Sat, 18 Sep 1999 15:27:21 -0400)
Reply-To: Adam Back <adam@cypherspace.org>
Ian Grigg writes in reply to anonymous:
> [...] Did we define electronic cash yet? I suppose you're
> going to say that it includes blinding, so that's another point
> of distinction between our viewpoints. Not that I wrote the
> above, but it seems accurate and useful.
I wouldn't say ecash has to use blinding, but I would argue it would
be a misuse of the word "ecash", if something which was revocable were
dubbed ecash.
With that definition it is not technically possible to implement
electronic cash at all without tamper resistant hardware, because
reliance on a mint, or double spend database means your "cash" can
become worthless over night if someone (say a government) decides to
switch off a computer (the one holding the double spending database).
This is because the value isn't held by the bearer, it is secret split
between the mint (in it's double spend database) and the bearer (in
his token), rather than being held solely by the bearer as the token.
Real ecash would be something which is really bearer, the value should
lie solely in the instrument. (Though clearly it's market value may
alter, the value should not be revocable by the removal of an entry in
a data base or book entry system.)
However the closest you can get in software is blind ecash -- yes the
server being shutdown could revoke the value of your cash -- but the
server can't discriminate and single out a single user because of the
blinding -- it has to revoke all value at once. And this is probably
as good as it gets for ecash.
Several companies have been misusing the term cash (present company
excluded of course -- systemics, webfunds, e-gold, digigold are not
calling their systems cash.)
I'm thinking of things like netcash -- more like net checks, etc., or
the typical credit card amortizing approach dubbed as "cash".
I can only presume the predilection to call these traceable book entry
payment systems "cash" comes from marketroids who want to borrow
cash's good PR -- "cash is king", cash is for anonymous,
instantaneous, irrevocable use.
Adam
