[E-Lang] Hash Chaining & Capabilities, Proposal #2d: Deputizing Remote Vats

[Nikita Borisov]

Bill Frantz writes:
>(4) To protect from double spending, Bob must immediately clear the coin
>with the bank, which is why the protocol is online.  Bob can be identified
>if Alice and the bank cooperate.
>
>The offline protocol modifies the online protocol by:
>
>(0) Bob creates the coin, blinds it, and sends it to Alice.
>
>(1) Alice also blinds it with her own blinding factor.
>
>...

I'm not sure that I would call this an offline protocol, since at step
(2), Alice still has to interact with the bank.  It just shifts which of
Alice and Bob talks to the bank.  The offline payment systems that I'm
familiar with rely on auditable double spending; i.e. the protocol is
payer anonymous if a coin has been spent only once, but the payer's
identity is revealed in the case of double spending.

- Nikita