Hi guys, glad to see you are now up and running with Bitcoin! I've sent them a small donation. I've been talking to the two principles at VirtualDoctors.org and we are all in agreement that they want to try and get the Bitcoin economy kick started by buying what equipment they can find from feasible suppliers in Bitcoin. I and some of the other community members are going to help out with this. Can anyone suggest reliable places to buy computers and digital cameras from in the UK with Bitcoin? I'm also working on a few UK suppliers to start taking bitcoin so watch this space... |
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See if BIPS works for you. For CustomersOpen BIPS in your Mobile browser, sign in, and you are able to use the phones camera to scan QR codes.   For RetailersMobile Checkout / Point of Sale to generate a payment address for the customers, uses responsive web design to accommodate any device screen size. See example: https://bips.me/checkout/mobile/cb  Thanks for this. I am setting up a number of retailers in Brighton to accept bitcoin so I will try this out. |
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There should be a wallet app that can generate digital paper wallets on cellphone of specific amounts.
Customer just need to show that QR code (Private key) to retailers webcam and it should sweep funds.
ie:
1.Retailer tells customer to pay 55.5$
2.Customer generates a QR code for 55.5$ on his cell and shows that on retailers webcam/machine
3.Retailers App scans it via webcam and sweep's all funds to a new private key.
This way, there will be no double spend possible.
Very nice. Does anything support this at the moment? Surely in this scenario one could still execute a double spend attack, but with different parties: if the customer also used the private key at the same time it would be the customer's payment verses the retailer's payment and who's ended up on the longest blockchain? |
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Fixed Payment Address Per Till
One approach I can think of to make rapid payment in a retail environment is as follows:
1. Customer scans a printed 2D barcode displayed at the till to get payment address. This constraint means that the address all customers pays will always be the same.
2. Customer sends agreed amount.
3. Retailer confirms funds received by checking blockchain, (e.g. blockchain.info)
Issues with this method:
'Double till attack': The retailer is using the payment amount and time as joint keyfield. In retailers with more than one till on a shop premises two customers who collude could go to different tills and purchase the same items at approximately the same time. Each of the two till attendants then sees a single transaction appear on the blockchain for the right amount to that address. Unaware that there should be two matching transactions each till attendant would then be satisfied that payment has been made and the colluding customers leave having effectively purchased matching goods at half price...
Solution: have a different payment address for each till. Or is there a quick and easy way for the retailer to generate a payment address per customer...?
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Can people please recommend me some bitcoin wallets to use to make payment in a retail environment. Basically I want to be able to wonder into shops, restaurants and pubs and be able to pay in Bitcoin over the till. I see this as currently breaking down into two main divisions. 1. Different approaches to make payment in a retail environment: • Fixed Payment Address Per Till • bips.me2. Wallets to use on the move suitable for mobile and tablet such as on an android mobile device: • blockchain.info wallet - seems to have many issues. • Bitcoin Spinner for Android - Anyone used this? • Mycelium Wallet, available here for android. If I get enough info I may make this thread an official list. Please be aware some websites may contain malware that could steal your cryptocurrency. No assertion is given for the authenticity of the organisations listed here or quality of the goods and services they provide. Myself and bitcointalk.org cannot be held responsible for the contents of other websites. |
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I'm glad to announce that I have now signed up the VirtualDoctors charity to take Bitcoin! They are a UK registered charity that provides telemedicine to remote African villages. They are good guys and need your help! Please donate if you can! |
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Thanks for this list, i keep checking on it (the URL in the above link is wrong, the site needs the www. (as the site is not found without it)) Thanks Ford Thanks. Fixed! |
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Just sent some FRC from my wallet to Vircurex and the confirmations are taking ages. Are there any issues with the difficulty adjustment? Any ideas why this is?
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Ravenscourt Design & Paul Christi Artists wants me to convey that they were having problems with their email servers which are now fixed.
Anyone who wishes to discuss commissions may now do so over email. Any emails sent in the last week should be resent.
Thanks.
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Can someone explain to me how Digitalcoin actually defends against double spending attacks?
I don't see how a block generation time of 20 seconds stops an entity with >50% of the network hashing power building the block chain faster than the rest of the network, no mater the time interval..?
Simple, it doesn't. It simply is "marketing". The blockchain DOES prevent double spends (once sufficiently confirmed) unless the attacker has enough hash power to rewrite the chain. Then again all blockchains do, that is the purpose of them. Then again a 20 sec block time that should be the first clue as to the knowledge of the developer(s). Ok, that's what I thought, it's just not true. Shame. I asked because the MetaLair decentralised exchange has a mechanism to defend against double spending attacks within a pre-agreed window based on a proof of work mechanism; I thought perhaps Digitalcoin had come up with a similar design based on proof of work. |
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Can someone explain to me how Digitalcoin actually defends against double spending attacks?
I don't see how a block generation time of 20 seconds stops an entity with >50% of the network hashing power building the block chain faster than the rest of the network..?
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My baby has arrived and it's twins!
Thanks Smoothie.
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why even post something like this.
unless you have evidence from the horses mouth so to speak, leave all speculation where it lies.
+1 |
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But now you can get it on a coin! Eventually... These addresses belong to me. I wasn't really expecting anyone to catch on to those transactions in the blockchain, but I plan to use them on physical Bitcoins in the future. They have been generated and stored offline, and will be air-gapped even to the point of printing them for usage. Certainly, there is a risk in people trusting me, but I hope to build up a reputation as Casascius has done. I think these coins will turn out quite nice with specialized and completely unique firstbits!
I've stopped generating them. I found around 36k of a 151k dictionary. I don't plan to generate any more - I have plenty for what I plan to do with them. There are still a number of good patterns, names, and English words yet to be claimed. I would love to see other people generating them and making use of other unique firstbits combinations.
Cam you or someone else please explain to me the methodology by which you got 0.00000001 transactions to register on the blockchain, assuming individual transactions for > 0.001 are not permitted. It's total transaction size. Since the change address was larger than the minimum requirement, then the whole transaction is allowed. You couldn't (easily) spend the 0.00000001 BTC out of one of those addresses by itself, but send 1 BTC to it, and you can pull 1.00000001 out. Ah, makes sense. Thanks. |
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Thank you for organising this James! I spoke to the Landlord at the King William IV pub and he can confirm they are setting up to take Bitcoin. So I've added it to the list.  All: Could we get some photos of the bar and a bit of info to whoever makes it over there to pay in BTC. I'm also going to post him some Bitcoin accepted here window stickers. Keep up the good work! |
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These addresses belong to me. I wasn't really expecting anyone to catch on to those transactions in the blockchain, but I plan to use them on physical Bitcoins in the future. They have been generated and stored offline, and will be air-gapped even to the point of printing them for usage. Certainly, there is a risk in people trusting me, but I hope to build up a reputation as Casascius has done. I think these coins will turn out quite nice with specialized and completely unique firstbits!
I've stopped generating them. I found around 36k of a 151k dictionary. I don't plan to generate any more - I have plenty for what I plan to do with them. There are still a number of good patterns, names, and English words yet to be claimed. I would love to see other people generating them and making use of other unique firstbits combinations.
Cam you or someone else please explain to me the methodology by which you got 0.00000001 transactions to register on the blockchain, assuming individual transactions for > 0.001 are not permitted. |
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Could the buyer not vanity generate a matching address later?
Firstbits belongs to the First address in the blockchain that starts with those bits. So, no. At last a clear definition! Thanks.... |
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