Banque des Cypherpunks

[aba at atlas.ex.ac.uk]

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David Murray <sdavidm at iconz.co.nz> writes:
> One avenue of safety - shepherding the idea through SEC etc scrutiny
> so as to render the venture completely legal seems to lack something
> of a c'punk flavour. After all, one idea that some of us are quite
> taken with is that strong crypto and the changes it brings are not
> only important (they are), nor good (as Tim has pointed out - it
> depends where you stand) but *inevitable*.
>
> So, how safe would a cp style bank be today?
>
> [feasibility analysis of blacknet style payment system]

If you haven't, you should read Doug Barnes <cman at communities.com>
recent postings on the current state of money laundering regulations.
Chilling stuff.  You can bet they are not going to like the payment
system you described, it's it's methods of transfering funds to and
from US bank accounts would be open to many of the anti-money
laundering attacks.

It would put a lot of strain on the remailer nets to have the likes of
FinCen, FBI, CIA, NSA etc. after them.  It is the legal impliciations
which are the problem, if they don't like what you are doing, and can
hold that it is illegal, they will come after you with excessive
force.

Even it you could get away with it, a purely anarchistic system has
the disadvantage of lack of take up: if no one is accepting your
e-cash, you can't buy things with it.  It could be made illegal for
people to accept your e-cash, at this point only people acting
anonymously will be using it.  

I think a possible approach is to work in two stages: to first work
towards wide use of ecash, as privacy preserving as feasible with
government imposed restrictions, and then in the future work on
improving the level of privacy.

The two stage approach I think is more likely to succeed because while
there is no payment infrastructure, the hard-line blacknet style
operations run counter to the aim of speeding the uptake of ecash.

It seems to me that payment systems that escape jurisdictions by being
in cyberspace protected by strong crypto, whilst perhaps inevitable
long term, are still some way off.

I think it is useful to explore what could be achieved by getting
something less abitious working first.

I like the distributed anarchic approach too, but lets first find
peoples opinions on what is possible within the system, and see if
anything useful would be possible with these constraints.  

I would like to hear views on whether the best that can be achieved
with such constraints would be a step in the direction of a more
desirable system (with better privacy guarantees), or whether it would
instead be detrimental to the cause, say perhaps by contributing to
getting a non-privacy preserving scheme immovably fixed as a standard.


There are several approaches to ecash systems that I am aware of:

1. no anonymity - most current systems

2. "trust me" the schemes which claim anonymity, but in reality rely
   on your trust in the bank. eg Mondex

3. clipper-cash (Jakobsson) here you get to trust a (supposedly
   independant) third party

	http://www-cse.ucsd.edu/users/markus/
	http://www-cse.ucsd.edu/users/markus/revoke.ps

4. blind signatures (Chaum, Brands)

	http://www.digicash.com/
	http://www.digicash.com/publish/pu_sc.html

5. or agnostic server (Doug's paper)
   (blinding as well, just avoiding Chaum's patents)

	http://www.communities.com/paper/agnostic.html

6. anarchy - remailer net, blacknet type operation


I would discount 1 & 2 as outright undesirable, and already available
anyway.  6 would cause the regulators to throw a fit.

Of the remainder 3, 4 & 5, I think the most likely to be acceptable to
regulators is 4: clipper-cash.  Next come 4 & 5.  Chaum's blinding,
and Doug's agnostically blinding proposals.


What do people think of clipper-cash?

Basically it sets of a scheme where you have an ombudsman who is
supposed to be acting on the consumers behalf.  Revoking privacy
requires the cooperation of both the bank and the ombudsman - the bank
on it's own can't strip your privacy.

Down side: to get such a scheme past regulators the ombudsman would
probably end up being a government body, or one beholden to
government, such as banks are with all the current banking regs, re
Doug's last two posts on the subject.

The problem with clipper-cash see is that it is just as the name
implies: private until you are investigated, or until the regulators
decide to go on a fishing spree.  But better than no anonymity.

Technologically it would be possible to have multiple ombudsmen, or
even have the recovery key be secret share split amongst ecash users
in such a way that some chosen percentage of agreement would be
required before cash could be traced, or revoked (made worthless).

I would presume that the more ombudsmen there are, and the less
amenable they are to government pressures, the less likely the payment
scheme would be to be acceptable to the banking regulators.

Does clipper cash satisfy any cypherpunk goals?  Or is it the ecash
equivalent of the hated clipper, and clipper II initiatives?

A blinding agnostic or openly blinding signature based server would
obviously be preferable, but could you get such a system approved by
the regulators?

These are just questions, to see what people think are the optimal
configurations from a cypherpunks perspective, and how close to these
ideals a payment system could be and still get past the regulators.

Adam

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