-----BEGIN PGP SIGNED MESSAGE----- In article <1.5.4.32.19960729084347.00331d14@giasdl01.vsnl.net.in>, Arun Mehta <amehta@giasdl01.vsnl.net.in> wrote:
At 05:15 24/07/96 -0500, Matt Carpenter wrote:
getting change from the merchant. Ian Goldberg pointed out that with the current ecash protocol, accepting change not only eliminates your anonymity, but that you also have to go online to make sure you aren't being cheated. But don't forget that you can use a slightly modified protocol to accept change anonymously, without having to go online!
I'm sure it should be possible for the merchant to electronically give you an "IOU" for the amount of change s/he owes you, no matter how small, without loss of your anonymity. Next time you go to the same merchant, the IOU could automatically be adjusted against the new purchase.
An IOU is equivalent to a coupon. You could even implement it as ecash issued by the merchant, but why? Using the "change" protocol, you can do it with real ecash just as easily. It's just as hard to get an HP48 to check the signature on change coins returned by the merchant as it is to check the signature on the IOU. An HP48 is unlikely to be able to do 768-bit RSA operations. However, it could easily have coins stored on it, transmitted to the store via a convenient IR port, or an RS232 connection. It's quite straightforward; if I had a store, I'd do it myself... - Ian -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBMf7/hUZRiTErSPb1AQFmCwQAj13wUVsf7zoUV9KuhnSIcEm1cELeHmfS voz+evncXOfr0aDEwb7y90iDwmm68Xrgq3IILKBLS+iu0s54LCG/jeBCPjW3b9oE nyZK47qRSmdHI7sqEwtWxlKrU4/trwY98q0nzZEIFvdJfRykPl0+Im0NBdRBYXVP i9h4uLuZz4k= =2ek/ -----END PGP SIGNATURE-----