Topic: What's the best technology to use for a face-to-face BTC transaction. - page 3. (Read 5024 times)

DeathAndTaxes and Gabi :  It literally solves every problem with the solution currently running. If you can't see what the problem is then why are you posting in this thread?

Because this thread is screaming:

"the bitcoin client sucks for what I am trying to do,  I can't send it from anywhere and I need to run back home each time to send bitcoins to people in a bar"?


Flexcoin is one of the only solutions that would enable you to access your coins easily from anywhere.  If bitcoin was perfect in it's beta implication this thread wouldn't exist.  The reason it was opensourced is so I (and other people)  could build on it.  

bitcoin client requires a 300+ meg download of the blockchain,  flexcoin doesn't.
bitcoin client cannot easily allow your coins to be accessed from any device
bitcoin client doesn't allow you to run it on your phone
bitcoin client doesn't give you an easy "cold storage option"
bitcoin client forces me to use long huge hash strings to send payments, flexcoin doesn't.
bitcoin client makes me pay fees for small transactions, flexcoin doesn't for flexcoin to flexcoin transfers, or flexcoin to e-mail transfers.
bitcoin client doesn't allow me to send people bitcoins via e-mail,  flexcoin does.

This list goes on forever....   perhaps the best way to say it is that thousands of people wouldn't use it if there was no benefit.  

Now look I am not saying "everyone should use it" because bitcoin was spawned by technically savvy people,  this was designed for ease of use for less technical people... and specifically for people that wanted to use their smartphone as a debit card..    

You're technical enough to build some huge complex system to pay a guy in a bar.... so you're type you'll most likely do that... which is 100000% fine because you might develop an even easier way than sending it to a qr code or ID... which would benefit everyone.

but as it stands now,  flexcoin is the easiest way to solve the problem that was posted in this thread...  

Or maybe not.

Remember guys, do not trust anyone.

Earlier I was proposing a solution for scenario "b" ...if the buyer does have a smartphone, I would say right now the best option is to use one of the wallet services (most of the exchanges or flexcoin or instawallet)...make sure whichever one you choose, it supports HTTPS to protect the buyer from an untrusted internet connection.  Just have the buyer move the needed coins into the wallet, then when you get together, send them to the seller's wallet (you can email the bitcoin address to the buyer...or turn it into a QR code for scanning/copying).  Genjix mentioned bit-pay...on the seller side, you could use bit-pay, but we target merchants that offer a range of products to many buyers (either online or physical).  It sounds like this is just a one off transaction, in which case there's not really a need for bit-pay (on the other hand, if you'll be doing this a lot, bit-pay would be helpful for managing it).

Some of us prefer not to centralize a perfectly good decentralized network.  My fear is that replacing USD banks with BTC banks is a dubious solution.  Eventually Bitcoin banks will get large, get shareholders, and have a never ending need to extract more and more and more value from users.  If I want to use a bank I will use a bank or Paypal.  I can send Paypal to anyone with an email address in seconds.

I don't see what solution Flexcoin solves?
Bitcoin is decentralized.  Paypal is not.  Flexcoin is not.
Bitcoin requires no trusted third party.  Paypal does.  Flexcoin does.
Bitcoin allows peer to peer transactions.  Paypal does not.  Flexcoin does not.

If I want ease of use, centralized, and requiring a trusted third party I will use Paypal.

Look at the conference I sent my bitcoins from my iphone using the flexcoin system to the bit-pay system ... funds got there in seconds....   We have several thousand users that use it specifically for person to person (IE: in a bar) bitcoin transfers.   as noted it has QR support even if you didn't want to type in the guys username.

Lug around a laptop or try to make some huge system work... or just flexcoin it...  but do whatever you guys want..  I can only tell you what I do and a few thousand people do.    It supports QR codes,  it even supports the iphone "bookmark icon"  it's specifically designed for mobile.   You can even send bitcoins to an e-mail address...

This.

Buyer needs to be sending coins from equipment he owns/controls.  Not doing so is dangerous.  If Buyer uses seller's computer (hey just log in to this computer here) to pay via a waller he needs to trust seller not to perform MITM attack.   For extra security buyer shouldn't connect to seller wifi (instead use smart phone 3G connection).  

To make getting correct BTC address to pay to most smartphone bitcoin wallets support scanning a QR code.  You simply give the buyer a QR code to scan and he sends coins to that address.

This way both parties use trusted equipment and independent network streams.  Neither system connects to each other (air gapped).  The "trust" only happens in the blockchain.  Both parties trust the block chain thus don't need to trust each other.

Or you could just tell the guy to send it to flexcoin id : president or whatever...

It's the whole reason we built flexcoin is for mobile payments.    QR code support,  etc..   or you could lug around a laptop .... 

Edit: the solution applies to scenario "b" in the OP

I don't know what tools can currently do this (if any), but the following would seem the best way: 1) have the person send the bitcoins to a new address, 2) have them print a QR code that encode the private key, 3) meet up and provide you with the printed QR code, 4) scan and sweep the funds into your wallet.  A tool that makes this easy would be nice...it would make use of the casascius shortened key format if the size of the QR code is a problem.

This is harder to do right now because it involves tools outside of the normal client right now, but I think eventually it might be common for these kinds of things. Similar to the Instawallet idea, the payer could create a "Paper Wallet" with an address and private key (The easiest way I know of to make a private key & address pair right now is an external program like vanitygen or https://www.bitaddress.org/ though you need to either trust their code or verify yourself that it's correct). He sends to the address the amount that he wants to spend, and then just gives you the private key when he gets there. You redeem it by entering it into an online wallet like Mt. Gox or, if you have the key import patch applied, importing it into a new wallet and transferring the money to your normal wallet.

You in theory should wait for confirmations if the payer is trying to scam you, but they'd have to be trying to pull off a double-spend attack. I think for most person-to-person secondhand sales, you've got about the same risk as the chance of them paying you in counterfeit Federal Reserve Notes. It could happen, and you could wait for a confirmation to make it much less likely, but I doubt that it's worth waiting for more than 1 confirmation, and for most items you probably don't even need to wait for that.

Okay, so I'd have a print-out of my bitcoin address qr handy (maybe made with Wolfram Alpha) and the buyer scans it and enters the amount - what app is the buyer using on his Android smart phone?
I'm confirming, say on my PC - but need to wait 10 or 20 minutes.

This sounds workable and has the advantage of no counterparty and we can change the amount easily if we're haggling. Only disadvantage is that it requires a smartphone.

android smart phones are the most reliable for making this kind of transactions, you let him scan you address qr and send payment over his 3G or your wifi internet, doesn't matter actually because bitcoin is designed to work in a non-trusted environment.
You should chat or invite the buyer a coffee while you wait for confirmation (10-20 minutes). It makes you be more social in the end cause you have to be in contact while you wait for that confirm

edit: option 2 would for the buyer to handle you an usb stick with a wallet.dat file that has the wanted amount. You could close your client, swap the wallet with a symbolic link, start the client again with a -rescan param, transfer the funds to an address you own.

edit2: i proposed the only options i would trust in a face-to-face transaction  

no big deal.

Smartphone or laptop, that's all. You give him your address and done. I suppose he has enough brain to be able to type your address in the phone... If he is so idiot, print it in a qrcode.

The wallet idea is nice but less safer. He give you the wallet with the btc inside it but unless you move that btc in another wallet, he can still move them in another wallet...

Interesting - so he'd preload a wallet with the agreed amount, and then he'd give me the keyphrase, which I'd enter into my browser and transfer the funds.

Think this is the winner so far!

Awkward to acquire in advance and difficulty with change. Also counterparty risk (third party again).

Buyer really should bring a smartphone. Then you just use the Bitcoin app.

Bit-pay is very handy if both have cell phones.

The third party thing is no big deal since they send you either cash or Bitcoins at the end of the day.

Good idea! Ask your buyer to get those stone age physical money tokens!

First things that come to my mind:
* your trading partner might not trust your internet
* he might not have a smart phone
* he might even not have a printer

What he can do though is charge an instawallet with an easy to remember secure link.
MyPaymentForThatAwsomeVHSCollection

He wouldn't even need paper on him and you may transfer that money to your wallet while he is at your house.

Casascius or Bitbills?

That looks promising, but appears to require a third-party intermediary (and two smartphones with internet connectivity).

Am looking for the best way to send bitcoins rather than a promise from a third party to send bitcoins at a later point.