A gradual fair exchange (layman term) is a form of fair exchange protocol where Alice will transfer 1 bit to Bob then Bob will transfer 1 bit to Alice. The flaw with this protocol is that the party which starts first may lose out as after Alice transfer her final bit to Bob , Bob may choose not to transfer his final bit to Alice.
An optimistic fair exchange is like a normal fair exchange except that in the event of a dispute , there is sufficient evidence to show who misbehave during the protocol. An arbitrator is present to settle the dispute.
- I would like to know if there's an fair exchange system which combines both optimistic and gradual fair exchange protocols such that I get the best of both worlds? How would it work if its exists?
- Is it possible to make gradual fair exchange protocol any fairer, if yes how is it done?
- I would also appreciate if someone can explain to me how is "evidence" gathered during the optimistic fair exchange protocol?