Bitcoin Forum

Bitcoin => Project Development => Topic started by: Wouter Drucker on April 02, 2013, 05:43:06 PM



Title: Bitcoin + Vending Machines Proposal
Post by: Wouter Drucker on April 02, 2013, 05:43:06 PM
Proposal. 'Bitvendor'. Bitcoin + vending machines + p2p trade.

https://docs.google.com/document/d/1bq43H8rCY9I8PD-1wstDd65ngPuQweccWdMySQ4HjtM/edit?usp=sharing

 :-*

I have allowed comments on the page, so feel free to add your 2 Bitcents.


Title: Re: Bitcoin + Vending Machines Proposal
Post by: dance4x on April 02, 2013, 06:04:17 PM
There is probably an easy answer to this question, but what about the time it takes to confirm bitcoin transactions for something like a vending machine?

Edit: Nevermind. Googled around and found the answer to my question.


Title: Re: Bitcoin + Vending Machines Proposal
Post by: Wouter Drucker on April 02, 2013, 06:22:25 PM
There is probably an easy answer to this question, but what about the time it takes to confirm bitcoin transactions for something like a vending machine?

Edit: Nevermind. Googled around and found the answer to my question.

What is that answer? I'll add your Q and A on the doc.


Title: Re: Bitcoin + Vending Machines Proposal
Post by: Stephen Gornick on April 02, 2013, 07:23:49 PM
what about the time it takes to confirm bitcoin transactions for something like a vending machine?

Just make sure it is uneconomic to attack.

The Finney attack is nearly 100% successful but it costs $4 per second to pull off.  So for anything sold worth more than $20, make sure to delay it a few seconds. 

A race attack isn't guaranteed to succeed (maybe one out of 40 attempts would succeed), but it is cheap to attempt.  But if I end up with 39 frozen burritos just to get the 40th one to spit out "for free", I'm not going to try.

Now let's say there is a change machine that converts bitcoins to quarters at a laundromat, with no fee.  An attacker could sit there all day and profit from the successful attempts and break even on all the unsuccessful attempts.  So that's not a good candidate for 0/unconfirmed transactions.


Title: Re: Bitcoin + Vending Machines Proposal
Post by: Wouter Drucker on April 02, 2013, 07:57:15 PM
I don't understand this but I'm including it in the doc just the same. Are you saying that you just wouldn't let the network verify, in order to reduce the 10 min. it normally takes for a transaction? Use some other kind of safety measure?

 :P