Bitcoin Forum

Scenario: paying with bitcoin using a mobile wallet at a coffee shop or other brick and mortar store.

Current solution(s):

• at checkout Merchant displays QR code for scanning
• mobile wallet user puts their wallet into scan mode, scans the merchant's QR code which may be a payment request QR (bip 70-73) or bitcoin address QR.
• Customer (traditionally) confirms the payment amounts and wallet handles the rest.

Problems with current solution:

• Merchant is required to have a screen that displays a QR code.
• Displaying a QR code for all customers may be confusing for non-bitcoin customers, and thus may require bitcoin customer to click a button on payment terminal indicating they wish to pay with bitcoin. Then the QR would be displayed.
• Drive through is even more of a challenge. The mechanics of scanning like this are awkward if it is the customer that must scan the merchant's code. Putting wallet into scan mode and reaching out car window towards merchant who is also reaching out with their QR screen can work, but merchant may not know what customer is doing? Why are they pointing their camera at me? Oh they want to pay with bitcoin. Weird. Or merchant must display a fixed screen for all customers which has the issues discussed above and also requires proper alignment (car window to screen).

Alternatives: It is proposed that we provide a mechanism where the current model can be 'flipped around' and allow the merchant to scan a barcode displayed on the mobile wallet to initiate a payment flow.
Why it is good:

• Allows alternative to X509 certificates in bitcoin payment protocol. Customer generated QR code can have one time code or optional encryption key that can only be intercepted by another camera in the immediate area.
• Allows merchant to leverage existing barcode scanning hardware or does not require more expensive screen terminal
• Does not require customer to indicate they are paying with bitcoin. At drive through customer can extend phone with screen side up prominently displaying a barcode, which merchant will scan and merchant POS can then determine what kind of barcode it is (as they may allow payments of other kinds using barcodes)
• Avoids alignment issues at drive through
• Letting someone scan your phone is easier than scanning someone else's code (so better for customer).
• Customer generated QR can provide a mechanism (url, phone number, email address, etc) as to how a standard payment request should be delivered to them.

Successful non-bitcoin implementations of this kind of user experience: Starbucks app, Mobile boarding pass. These work very well and are based on merchant scanning customer not the other way around.

Issues: Getting the payment request to the mobile wallet is still an issue. However as indicated the customer generated QR can contain possible protocols for this. Wallet may require a 'backend' server to communicate payment requests, which wallet solution providers can implement. Alternatively payment request can be sent via text message or email. Customer's qr code can contain phone number or email address and mobile wallet can intercept text message an act on it.  However, revealing a phone number or email to merchants is sub optimal.

Alternative solutions: Clearly NFC terminals can avoid this however, NFC terminals and devices are not pervasive.

Why can't they just hand the cashier a bit coin card

Have you seen our Coinkite POS? We have a ton of these in the field now,
B&M stores that don't even have websites :)

https://coinkite.com/faq/terminal

That's exactly what I was thinking of! I saw a Bitcoin bar/restaurant using this and everything went really smoothly, paying with Litecoin as well is pretty awesome.

Edit: There's the exact video I saw there too that shows it all: https://www.youtube.com/watch?v=w2nRDFoeQHo

Thanks I just took a look at your video. It is pretty cool, however doesn't meet of few of the things on my wish list.

Coinkite doesn't let you pay with a mobile app unless you first scan the merchant QR code. Right?

When using the the Coinkite card you use it like a standard debit card, which is ok, but it requires the standard debit card flow which is fine, but I'm looking for something even better.

Something like the starbucks app to me is ideal. Advantages: Merchant can scan you instead of the other way around, funds are withdrawn without your confirmation (but limited to a pre-loaded amount). Fewer steps, works at drive through because you extend phone face up with barcode which merchant sees and scans, no extra screens needed by Merchant to display QR (or print one out and hand it to you), can leverage existing barcode readers in some cases.

We do have one more trick, we support QR login. The retailer scans your phone's QR with the terminal then you can just see your account and pay with a PIN!

Look on the bottom of this page https://coinkite.com/accounts/cards

Because that it so year 2013. But more seriously, see my comments to the Coinkite guy. Bit coin cards, like Coinkite and others (is there a good list somewhere?) do offer some good features, but honestly I do like paying with my phone better than with cards. If I'm in the drive through or even standing in line, chances are I have my phone out, doing something so I don't have to reach into pocket again for wallet. Let's me ditch the wallet entirely if I want.

So I'm looking for mobile solutions, not old world debit card type flow (no offense).

We build Coinkite to support both, you can receive payments from phone wallets (API coming soon for you to even code line up pre orders) or convenient Debit Cards. I really think that in payments the more options the better, different people different wants/needs.

I see.  You're right, that is the future.

A lot of folks already use bar code (not sure it's qr) on their phone as boarding pass to board a plane, so it probably won't be long before you can do that in a drivethru.

Well, that is getting there. I couldn't follow that link though, sent me to a login page.

A few things I would want:

If retailer scans my QR I just want it to pay them. Yes pay them whatever they request (within limits). So maybe I have a limit set to $25. Merchant scans the QR and then requests payment for the $2.50 coffee and gets paid automatically. If they are bad and request the wrong amount, well worse case I'm out $25 but then I can report this, or ban them inside the app, etc. So it's unlikely to happen.

No pin should be needed (although recommended that phone be locked with pin or optionally detect this and only require pin if phone doesn't have security enabled).

No confirmation of payment amount should be needed.

Scan, and done.

Also, while I appreciate Coinkite is building a business and wants to do things their way and have merchants use their POS terminals etc, at a broader level, if there were some standardization for this kind of flow, then other wallet apps and service providers could implement it. I think if we see too many proprietary solutions that all work differently it is not a good thing necessarily.