As per your post on Kickstarter.
I fear on this you may be so far ahead of the curve you can't even see it. I've seen so few things payable with bitcoins, the exchange rate fluctuating madly, and the difficulty converting to and from bitcoins etc. etc. I'd be surprised if the ring would be used anytime soon.
And I'm someone who's got a MtGox account, traded 3 figures sums, and has a ASIC mining rig hopefully here soon (you can guess who I ordered it from). No, I'm not a kingpin, and haven't been doing it for years. But I'm not so green that my first question is "what's a bitcoin".
So back to your questions specifically:
- Experience as you outlined, make payments from a "wallet", simply by bumping the ring NFC style.
- Your limits sound sensible. As current payment systems pretty much all accept cards, perhaps random pin number requirements, and or pin if over threshold.
- Do you need to? If we're talking bitcoins, isn't the idea anyone can write a wallet, or bitcoin accept, store, transfer software. So you're not beholdent to the banks.
So going back to 3 for a second, what are the challenges I see:
- Getting money into and out of bitcoins easily (as easy as falling over) and quickly (instantly) for most normal people in the UK.
- Getting one/all of the payment processing providers used by merchants to:
i) Provide NFC machines widely.
ii) Accept bitcoin currency.
iii) Either a) convert it at know rates to normal currency for the vendor. b) peruade all to accept bitcoin
- Persuading vendors to agree to the above.
So to me looks like pushing water uphill, but you're nothing if accepting of a challenge. And if you pull this off, you'll certianly be at the forefront of bringing bitcoin to the masses, let alone NFC payments!
Being from the US, I have to say that I have found no use for Bitcoin - I have looked at it and tried but it's just not used all that much.
I personally, would much rather see a Google Wallet integration.
I'm a bitcoiner and was going to use my NFC (private) as a cold storage wallet, so security is paramount.
And offtopic, there are already pubs that take cryptocurrency as payment. The Blue Anchor in Oxford takes Feathercoin (the feathercoin developers are from Oxford).
I was talking to them about it as I've been given the go ahead for accepting cryptocurrencies in the Student Shop I'm currently setting up (I'm a mature student studying architecture in Oxford).
I was looking at using my NFC ring (public) for payments in the shop (looking at using a Nexus 7 for the payment system).
If the students have NFC rings/devices then it's certainly easier from my point of view...
Oh yes, I mean, I detest physical money, and all the inconveniences it causes.
The moment I can do away with carrying physical money is a moment I'll be a very happy person. I genuinely don't mind if its a mix of traditional card and something like an NFC alternative. Indeed that's where I see things like the NFC ring, as the replacement for coins/notes in the places cards don't currently work, from the corner shop, sandwich van. Small amounts, should be super quick.
So I'm all for NFC wallet and using it daily, quickly etc.... just wasn't sure Bitcoin was the solution that would get there first.
I suggest you keep a small amount of money (~$20) at a bitcoin address, and then set the ring's public code to that address, and the ring's private code to the private key of that address.
To have someone pay you, they just scan your fist.
To pay someone you need to reveal your private key. This is less secure as once you have revealed your (unchangeable) private code to a payment terminal or another person, they can take all your wallet contents, and any money you add to that address in the future.
I recommend doing something like the electric NFC cards you get in stations. Show your private code to a scanner from a brand that you trust, and it takes the correct payment. Just be careful to only let trustworthy units scan your private code. (This is just like when you use an ATM, and you check nothing else will scan your card.)
If the ring could "sign" transactions, that would be much more secure, but you need a bit of (powered) hardware for that. (I can can help if you want to go that route too)
If you don't want to create the wallet software for the ring these are two of the most famous wallets for Android (no bitcoin for iphone for now thanks to Apple), you can talk to them and see how to integrate:
- Bitcoin wallet (the guy already has some interfaces to pay with bluetooth and probably NFC) https:-//play.google.com/store/apps/details?id=de.schildbach.wallet
- Blockchain, very famous and nice wallet https:-//play.google.com/store/apps/details?id=piuk.blockchain.android
NFC Bitcoin payments are a thing I have been dreaming of since before Bitcoins or NFC were invented.
The ideal solution here is to keep a private key on the ring, and actually have the ring itself perform the ECDSA signing, and then it's up to the merchant to propagate the transaction on the network. The one (HUGE) problem with that, is without any sort of display, or verification mechanism, the ring is just blindly signing any transaction requests sent to it, so anyone could just walk by and quickly grab all the coins out of the ring.
This version of the ring would not be ideal for these types of bitcoin payment. You still need at least a display to show how many bitcoins are going to be transferred, and physical buttons to approve/reject the transaction, and ideally a way to enter some sort of PIN. I imagine more of an NFC necklace for these complex transactions.
That said, there are plenty of awesome bitcoin related things that can be done with this version of the ring.
Team up with Andreas Schildbach (creator of the most popular android wallet) and have him build in an NFC locking mechanism. Keys would be encrypted in the wallet, and would be unlocked via a simple locking mechanism (similar to phone unlock). This is not very fancy cryptographically, and there are plenty of weak points to attack, but it would work, and it would be a good additional locking mechanism.
The real magic would be if Andreas could figure out how to keep a bitcoin private key on the ring, and have special NFC addresses in the wallet app. If you are sending from an NFC wallet, you have to tap your ring to send the transaction, and the transaction is signed on the ring itself. It's very important that the key is actually locked with a random PIN only accessible by the bitcoin wallet app, or anyone else can come along, like I said before, and grab the coins that way. If done right, the private key would be generated on the ring, and it would never need to leave the ring.
Team up with various web wallets and exchanges to implement an NFC authentication system. You load in your public key to the site, and they send down a signing request that you have to sign before you can do certain actions. This can be done already with client SSL auth, but I think some sort of json API would be more developer friendly. This suggestion really has nothing to do with bitcoins, but there happens to be a lot of bitcoin wallets and exchanges, as well as users who are demanding stronger authentication technologies.
There is a nice FAQ on payment protocols with BTC on the bitcointalk forums.
[removed link as this is my first post here.]
edit to try to put it back.
Some talk about Bluetooth but NFC yet.
I would like a tap to unlock wallet at least
just started in this also
My name is Andreas Petersson. I am the business developer at Mycelium.
We offer the Mycelium Wallet - the fastest and best Bitcoin Wallet. We are also the developers of the Bitcoincard (see bitcoincard.org) which is not released yet. We already support importing private keys and addresses (pubkeys). There is also a "cold storage spending wizard" that could be adapted to specifically support NFC ring.
You can try out how it works using any paper wallet.
The wallet is not in version 1.0 yet so it is labeled as "beta", and it is not actively promoted so far, yet we still have a userbase of thousands of users.
I think your NFC ring could be a nice complement to our software, because of our system architecture we are the only mobile wallet that allows seamless import of private keys.
you can find the wallet at
[b:3v3yi9qv]Please get in direct contact with me to discuss a cooperation.[/b:3v3yi9qv] You can get in contact with me on skype (andreas_petersson) or via email at email@example.com
or if you prefer our landline phone number, it is posted on
In theory, the Public key could be used as a receiving address. Nice easy and not a problem.
The private key SHOULD be used as a signature to enable a payment which would be processed (and checked) on your phone/tablet.
This would be the most secure way currently we could use the NFC ring.
Any wise person encrypts their wallet which needs to be unlocked to authorise a payment.... all the NFC would do is apply this.
I personally would advise a stupidly long randomly generated password because it wouldn't need to be remembered as it's on the ring.
Think of it as the pin on your debit card. The pin machine displays the correct amount and you authorise it with your pin number.
It's a pretty okay(ish) system and all we would do is replicate that system with a much more secure pin number (4 digits vs. a very long random alphanumeric password)
then set the ring's public code to that address, and the ring's private code to the private key of that address.
I think there has been reports of the private side of the ring interfering with the front side. Most likely, some NFC readers can be strong or smart enough to read both the public and the private side.
There are also methods, using special-made antennas and such, to scan NFC chips from a much larger distance. I probably read about it in news reports from some BlackHat or DefCon conference.
I don't believe it was hacked in the end, certainly can't find any follow up on it.
The ring is readable from an extremely limited distance, don't fall into the trap of thinking of it like just another NFC tag.