Topic: bitcoincard.org - page 7. (Read 29284 times)

Why kind of storage do these cards have? Or how long are the card to card transactions/messages stored?

Since every message/transaction is send to everyone in the network (because the network doesn't notice that a message reached the receiver) there must be huge amounts of data after a few days/weeks (like the blockchain).

Are there any specific details about how they are planning to prevent spamming/flooding?

The whole is based on the trusted servers. If the owner of a server (or a hacked server) sends false informations people can get scammed easily since the card has no other way to check the blockchain. Or does it take serveral servers to confirm a incoming transaction? So the risk could be minimized.

I don't think you get it. BitcoinSpinner / Electrum are fine on a smartphone and the scalability optimisations can be applied. Also entropy can be generated.

These devices are REALLY low spec. They are very very simple devices to simply sign a tx and hold a single key. In fact they are so small that it's tough keeping a bitcoin tx in memory.

It's not a problem for bitcoinspinner, which pretty much does the same thing for an android smartphone.  It would take some significant adoption rates before the server side was heavily loaded even for a low end server instance, and it's not like that can't be scaled up if the market is there.  I wouldn't expect that transfers from a bitcoincard are going to be free, they aren't for bitcoinspinner.


Not quite correct, as all signing is a reproducable process by necessity.  Also, any amount of entrophy can be aquired early, over a period of time, or by the wireless radio receiver by tuning to an off channel and digitizing the background noise.  There is no need for a radndome number generator because the digital receiver acrtually is one.


I'm sure that some future users will go that route, or simply buy smartphones with this kind of hardware included in the phone.


Mobile phones do, but smartphone not so much.  Not yet anyway.  Still, I want a dozen even though I have a smartphone.  I use my smartphones for a great many things, many of which are terriblely insecure.  Hardening my smartphone so that it could do any kind of mobile payments secure enough to keep any significant balance would be an inconvience in so many other ways.  If the devices are cheap enough, they have value as a secondary value storage device, even if they spend most of their time in my safe.  The mesh texting functions also make them independently valuable to myself to keep in touch with my kids when we are in public but separated from line of sight.  I could put some without any balance in the back pockets of my toddlers, so that I could vector track them with a smartphone app should they get loose in a crowd.  I could give one to each of my older kids so that I could keep tabs on them while they wander the Mall or the craft fair, and do so far cheaper than it would cost me to pay for a cell phone & service.  Cheaper even than a set of Family Radio Service handsets, and less publicly annoying.  I could give them away to my pre-teen daughter's click of friends as a texting toy, if they are cheap enough.

That's just my own, very real, use case.  I can think of a dozen other use cases off the top of my head, not the least of which is as an actual payments device for people who are 1) to poor or 2) too cheap to buy a smartphone (such as the third world bitcoin user model mentioned by others) or 3) those who actually do own a smartphone but are either beyond their effective 3G service range or 4) desire to have a backup method should their smartphone be physically stolen or 5) pwned or 6) busted or 7) simply a dead battery.  And then there are those who like to go camping beyond the range of their cell service and the camp store accepts bitcoins but doesn't have wifi.

Again, it depends upon the cost of the device.  If they cost under $2 each to  procure, I'll buy a dozen & one  or two hardware gateway dongles jsut for the location & texting features.  The bitcoin fuctions are just a bonus.

I too think this device will have the greatest success with developing nations where people can't offer a smartphone.

Usually different persons have different needs.

And while talking generally, at least initially the easier the tech, the better (remember iphone 1 couldn't even receive an MMS!).

Have you seen the specs? I'm not sure what processing you are referring to?


It is difficult to believe that these can work independently without docking at some point to dump data and build a new wallet.


That's why I think these are ideal for developing nations. They will not only appreciate them more, but will find more creative ways to use Bitcoin.

I have a question to people who think these are a winner.

The issue seems to be a social issue not a technological one. Do people prefer a secure dedicated device over a less secure mobile phone which offers a far superior featureset?

Random thoughts here:

- Devices are so low spec that it makes it difficult to implement any of the blockchain scalability optimisations that can be used for Electrum. Much of the processing is moved server side which assuming it ever did the volume that is mass usage, would be a serious problem.

- I’m not sure that the hardware on these devices can generate enough entropy. A friend (niekt0) told me that ECDSA (unlike other encryption schemes) requires entropy for each signing, not only for generating keys.

- I’ve seen an addon device for mobile phones that allows secure key signing to be possible via an attached USB or similar device. The functionality for a mobile phone is far more advanced that these low spec devices.

- Even if dedicated devices are more secure, mobile phones have more popular adoption. For small amounts of spending cash, their security is adequate. For larger amounts, larger devices or services are fine.

I want to wear one as a watch!

if they can build them for as cheap as they say these will be a real winner.

I suspect that this device is so far ahead of its time, that they will not be able to keep up with demand. I kinda hope they just license out the technology to anyone willing to market up-scaled versions and use the licensing fees to make the cheapest version possible for developing countries.

Sorry if this has already been mentioned, but if the cards can 'talk' wireless protocols, I suppose you could have a simple bridge-app on your phone to relay the data through the cellular network. Many people who have jailbroken iPhones and Android handsets would be familiar with this.

Nice product, by the way.

Yeah it should have the option to turn the card off or at least the tracking off.  Yes simple cover sleeve to act as a Faraday cage would also be a good idea to protect the card.

Haven't read all pages in this post, but simply creating a faraday cage around your card (simple copper sleeve) would eliminate a store "snooping" on where you have been in the store, outside, etc. That is... until you go to purchase something.

New blog post:

BitcoinCard in Vienna Day 1: Coffee, missing ATM's, and some testing! (Pictures)

http://blog.bitinstant.com/blog/2012/6/8/bitcoincard-in-vienna-day-1-coffee-missing-atms-and-some-tes.html

http://siliconangle.com/blog/2012/06/08/bitcoincard-puts-cryptocurrency-in-your-wallet-with-a-mycelium-smartcard/
"The Bitcoincard moves bitcoin economic interaction offline, which significantly expands both turnover and the target audience. But, most importantly, it makes the clustered local growth of a new free economy possible. Everything starts from the small and mundane, from the things that we encounter on the street everyday. All we need to do is to try to live while using each others’ services directly, without the participation of outside agents such as the dollar, and everything will be smooth sailing."

Also: I saw bitcoincard, and the device is legit. It has only minor kinks that are easy to work out.

I'll avoid posting more as they're quite sensitive to exposing their secrets right now, but the device is really cool. I'm hopeful for it.

First off:
- It's tiny. Credit card sized and < 1 mm thick
- Low cost (cheap device)
- Low power (runs off solar)
- Theoretically it should be secure, but I need to know more of their setup first to be sure their implementation is secure. I'm guessing there may be a couple of vectors they haven't thought of yet, but with proper help they should resolve this.

For merchants, it's trivial and safe to allow Bitcoin payments from these. They also look pretty nifty.

I can imagine one day, Intersango giving away a basket of these for free branded with our logo (or something). They are really cheap and simple devices.

This is false. It happens fairly often in fact that someone sends to an address and then debits in the same block. The only restriction is that the transactions have to be chronologically ordered in the block (due to the way bitcoin blocks are processed)

Really? An address can't be credited and debited in the same block?
Why not? I mean, why impose such limitation?

(I think we're getting off-topic... I'll open another topic about this)

EDIT: Here it is: https://bitcointalksearch.org/topic/cant-addresses-be-credited-and-debited-in-the-same-block-if-not-why-86377

I don't know why not.  Thus far the headers total about 16megs.


Why can't the gateway be a computer with a bitcoin node running?