From: Andrew Loewenstern <andrew_loewenstern@il.us.swissbank.com>
Date: Tue, 15 Oct 1996 21:06:18 -0700 (PDT)
To: scottb@aca.ca
Subject: Re: extortion via digital cash
In-Reply-To: <96Oct15.114214edt.15378-2@gateway.aca.ca>
Message-ID: <9610151846.AA00586@ch1d157nwk>
MIME-Version: 1.0
Content-Type: text/plain


scottb@aca.ca writes:
>  I was wondering, what if you demanded payment via Ecash,
>  through nym servers, aliases, etc.  From what I understand,
>  it is just like cash, ie: no record of transaction, but you
>  get the added bonus of not having to meet the other party-like
>  a fund transfer.

This has been discussed quite a bit on the list before and there is even a  
bit about it in Applied Cryptography.  Basically the extortionist must be  
careful in how he arranges payment.  The extortionist must create blinded  
proto-coins and send them to the extortionee to be signed.  Otherwise the  
extortionee can write down the serial numbers before sending the coins off and  
the extortionist will get caught when trying to deposit.

Some of the cut-n-choose protocols for after-the-fact catching of double  
spenders would prevent this from happening.  Because the proto-coins from the  
extortionist are blinded and the extortionee can't remove the blinding, it  
would be impossible for the extortionee to properly complete the protocol with  
the bank and pay-off the extortionist.


andrew