From: David A Wagner <daw@CS.Berkeley.EDU>
Date: Fri, 1 Dec 1995 15:31:15 +0800
To: cypherpunks@toad.com
Subject: digital receipts and cash
Message-ID: <199512010408.UAA04333@quito.CS.Berkeley.EDU>
MIME-Version: 1.0
Content-Type: text/plain


Digital cash protocols are starting to look like they could become very
popular and useful.

But under current proposals, there's one thing you don't get when you
spend digital cash: a digital receipt.

(Later, if the vendor reneges on the transaction, you'd have the digital
receipt to prove that you paid & the vendor is cheating you.)

This seems like it would be a really useful feature.  Does anyone know
if there are any *practical* protocols to do this?

ObCypherpunks relevance: digital receipts seem (IMHO) important to the
emergence of fair and robust reputation markets.  Discuss.

ObCrypto relevance: I've looked through _Applied Cryptography_, but the
protocols listed there aren't practical -- they require something like
100 rounds of interaction!  Can this be improved?