🚀 go-pugleaf

bs891@cleveland.Freenet.Edu (Robert Anderson) writes:


>Apparently David Chaum is one of the main people involved.
>I found a paper by him and 2 others in the Crypto 88
>proceedings which describes an electronic cash system that
>sounds like what DigiCash is doing.

>You go to the "bank", in this case DigiCash, and withdraw
>money by offering a "blinded" random number for them to sign.
>You can then unblind the number so that even the bank can't
>recognize it, but you can still spend it by showing the
>store the bank's signature.  The store then sends the number
>back to the bank and gets paid.

>The really clever feature is that the bank can't recognize
>the numbers as they come in from the stores in terms of who
>withdrew them.  That is, it can't unless you try to cheat and
>spend the same number twice.  Spending the money involves
>going through a little protocol with the store owner, and
>some randomness in the protocol ensures that if you do it
>twice, you'll reveal enough information that the bank can
>figure out who you are.  Then they can sue you, or at least
>shut your account down.

This protocol was not described in Chaum's 1985 paper and I have
been trying to figure out how he intended to prevent such counter-
feiting.  Can you please post or e-mail a reference to the paper
wherein it is discussed?