-----BEGIN PGP SIGNED MESSAGE----- Hello Hal <hfinney@shell.portal.com> and cypherpunks@toad.com H wrote:
"Simon Spero" <ses@tipper.oit.unc.edu> wrote:
[about fully-anon ecash] ...
There could be an issue of fraud, though, where Bob insists that Alice's coin was no good even though it actually was. ...
Cut'n'choose between Alice and Bob? Ie Alice asks Bob for half the blinds to check that the proto-coins are true? Apart from no-good proto-coins, is there any other way the coin could be no good? As for no-good proto-coins, it's Bob's fault, isn't it? Alice has a record of what Bob sent, and what she sent back. Anybody can check that the latter is a bank-signed version of the former. Given this, there's no need (from this) for Alice to know that the proto-coins are good (if they aren't, Bob's an idiot, but there's not much Alice can do about it - I guess given all the blinding factors the bank could replace the coin, seeing that it signed a worthless one). So Bob can't really fraud - unless I've missed something. An interesting question is whether Bob and Nick can now collude to expose Alice. Therefore Alice would at least want to verify that the proto-coins are true? Would that suffice? Or is that not necessary?
Still, I think this scheme has considerable merit and is worth exploring ...
Certainly. Jiri - -- If you want an answer, please mail to <jirib@cs.monash.edu.au>. On sweeney, I may delete without reading! PGP 463A14D5 (but it's at home so it'll take a day or two) PGP EF0607F9 (but it's at uni so don't rely on it too much) -----BEGIN PGP SIGNATURE----- Version: 2.6.2i iQCVAwUBMIyabyxV6mvvBgf5AQESsAP6AqZD+/nJVZxiV5UuPUTPvWNo/vOADAWz cz65Iw4u9SyqpQfO/sRxZneVCdsDDHi9K+iRFtI+cc5NFCKUVUC2Cop6ExzuCClL VgR5ILG+ECsw8V+FYHepkch96acgPtVVc3trYExWlr3lY5mYl4ccS9G3Mhn/PyPO Dq5eP2GEBEA= =8dxL -----END PGP SIGNATURE-----