Bitcoin Forum

Here's an idea for safe instant 0 confirmation payments at grocery stores, vending machines, etc. It would need to be implemented in clients, and that's why I propose it as a BIP (Bitcoin Improvement Proposals).

First scenario:

1- I go to my favourite grocery store and deposit 50 BTC. 10 minutes later they get confirmed.

2- Next day I come back, pick up some lettuce and digitally sign the following message:

"I pay 0.01 BTC"

Since the message is signed with the same address that previously deposited $100 to the store they can inmediately verify my identity, credit my account and give me the item.

Second scenario: Imagine the existence of a company named "Bitpayments".

1- I open an account at Bitpayment and deposit 10 BTC.

2- The hot dog seller at the corner now shows me his Bitpayment address and again I digitally sign a message: (or my Bitcoin app does it for me).

"I pay 0.02 BTC"

Bitpayment credits my account and gives the money to the hotdog vendor.

3- I can spend my 10 BTC at any street vendor, grocery store or candy machine that accepts Bitpayment.

It is essentially another layer on top of Bitcoin that allows safe and secure instant transactions for items that cannot wait for a confirmation.

The decentralized and cost efficient nature of Bitcoin would allow any store to accept prepayments for regular customers and smaller merchants such as street vendors could do the same thanks to new companies that would emerge.