R. Hirschfeld wrote:
Date: Thu, 20 Oct 2005 11:31:39 -0700
From: cyphrpunk <[EMAIL PROTECTED]>

2. Cash payments are final. After the fact, the paying party has no
means to reverse the payment. We call this property of cash
transactions _irreversibility_.

Certainly Chaum ecash has this property. Because deposits are
unlinkable to withdrawals, there is no way even in principle to
reverse a transaction.

This is not strictly correct.  The payer can reveal the blinding
factor, making the payment traceable.  I believe Chaum deliberately
chose for one-way untraceability (untraceable by the payee but not by
the payer) in order to address concerns such as blackmailing,
extortion, etc.  The protocol can be modified to make it fully
untraceable, but that's not how it is designed.

Huh - first I've heard of that, would be
encouraging if that worked.  How does it
handle an intermediary fall guy?   Say
Bad Guy Bob extorts Alice, and organises
the payoff to Freddy Fall Guy.  This would
mean that Alice can strip her blinding
factors and reveal that she paid to Freddy,
but as Freddy is not to be found, he can't
be encouraged to reveal his blinding factors
so as to reveal that Bob bolted with the


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