[Cryptography] Checkoin: physical crypto-cash

[Ron Garret]

On Jul 15, 2017, at 1:07 PM, Camille Harang <mammique at garbure.org> wrote:

> Le 15/07/2017 à 17:59, Ron Garret a écrit :
>> I can’t help but picture the following scenario: I accept a coin of the sort shown in the animation on your web site, the one with the scratch-off scratch-to-cash doodad on the back side.  I decide to cash the coin, so I scratch off the obscuring layer to reveal the word, “SUCKER!” written underneath.
>> 
>> rg
> 
> 
> Sorry I've read my answer again, I can see that it is not clear. When I
> say that there is 0% chance that a Golden Eagle coin doesn't actually
> contain the gold (aka written "SUCKER" on it), I talk about a genuine
> Golden Eagle produced by the official mint factory, I'd like to see if
> they took the risk of producing only one coin in their entire career
> that doesn't contain the gold, I bet there is not, that's why I say 0%
> chance. Of course fake Golden Eagle doesn't contain the gold, but the
> technology detects it right away, to produce an official Golden Eagle
> coin with its UUID registered on the blockchain you need to have access
> to their official private key.
> 
> Please tell me if it's still unclear.

The attack model is not that someone counterfeits a coin ab initio.  The attack model is that someone *copies* a *legitimate* already-issued coin and circulates the copy *instead* of the original legitimate coin.

rg