Hack DigiCash: Payee Anonymity

[David R. Conrad]

On Tue, 24 Oct 1995, Name Withheld by Request wrote:

> The  <--(blinding)--- payer <--(blinding)--- payee
> Bank --(unblinding)-> payer --(unblinding)-> payee --> payee spends money
> 
> The payee generates some digital coins, blinds them, and sends them to the
> payer.  The payer then makes a withdrawl from his bank account, blinds the
> coins again (or not, it really doesn't matter) and sends them to the bank.

If the payer doesn't add a blinding factor, then the only blinding factor
is the one known to the payee.  The payee could reveal this blinding factor
to the bank, destroying the payer's anonymity.

Right?

> The bank signs them, and returns them to the payer.  The payer removes his
> blinding (if any) and sends them to the payee.  The payee unblinds the
> coins and spends them at his leisure.  Privacy for all involved.

David R. Conrad, conrad at detroit.freenet.org, http://www.grfn.org/~conrad
Hardware & Software Committee  --  Finger conrad at grfn.org for public key
Key fingerprint =  33 12 BC 77 48 81 99 A5  D8 9C 43 16 3C 37 0B 50
No, his mind is not for rent to any god or government.