Re: [Taler] transaction state/history; fulfillment

[Sree Harsha Totakura]

On 01/08/2016 06:07 PM, Florian Dold wrote:
> First of all, we don't use HTTP 301 anymore (but HTTP 200 with a JSON
> body), due to limitations in some of the environments where we want to
> implement a wallet (in particular the WebExtensions API, where we must
> use an XMLHttpRequest that handles redirects transparently and in a
> different context than the merchant's page).

The web docs need to be fixed. They still list HTTP 301.

>> > If the customer gets the order number, then he can follow up on the
>> > merchant for not fulfilling the contract.  But then the merchant could
>> > simply say that the order confirmation is not given by him.  At this
>> > point the customer: 1. will lose some trust in the merchant and 2. can
>> > try to melt the coin.  If the customer succeeded in melting the coin,
>> > then it is just a case of something going awry at Merchant.  If not, it
>> > means that the merchant played foul and hence it this cloud be legally
>> > challenged.  I believe our auditor mechanisms help the legal proceedings.
> There's always more complex alternatives (using the refreshing protocol
> to check that coins were used, or using some time-stamping service), but
> the fulfillment signature provides a very simple way for the customer to
> prove that they payed in time *once* the contract's key can be
> associated with the merchant's long term key.  That association might
> only be available in future versions of Taler.  You're right in that
> currently the merchant_pub in the contract could be an ephemeral key.
> 
> Without the fulfillment signature, it's much harder for the customer to
> know that "I paid the merchant, the merchant knows that and I can sue
> him if he doesn't deliver".  If Taler contracts are legally binding,
> then they will have to have a short expiration time, and the merchant
> would be able to claim "the customer didn't pay before the contract
> expiration" and the customer has nothing to counter that claim.

Customer paid the merchant.  Now, what if the merchant were not to give
this fulfillment signature?

I understand that the fulfillment signature provides a legal evidence
for the customer.  But then an order number/confirmation can also
provide that evidence, because the customer can then be sure that the
merchant has deposited the coin and the coin deposited OK at the mint,
except in the case where the merchant sent a order number without
depositing the coin at the mint (why would merchant do that anyway?).

Regards,
Sree