bitcoincard.org

[unclescrooge]

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

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[MoonShadow]

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.

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.

- 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.

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’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.

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

- 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.

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.

[genjix]

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.

[btcash]

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.

[opticbit]

how flexible is it?  how easy is it to break?  water proof?  Will it Blend?

[NothinG]

I'm planning on pre-ordering 5-10 when they first come out.
Once I like the first batch, I'll show it off and get some people interested and try to gather some pre-orders so I can buy bulk of ~250-500.

how flexible is it?  how easy is it to break?

[BlackPrapor]

I wish I could buy some too. Before reading this thread, to me it looked more like a scam. Fancy video, not much info, tried to contact them - no reply, only a Bitcoin address to send the money. Once they show up here on the forum and give some real contact details, I might be interested to invest some real buck. Also, nodes at shopping malls is good idea, but what about other locations? Think cars (precicely trucks).

[BadBear]

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.

Is a sleeve like that possible? I thought cages had to be grounded to be effective?

[rjk]

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.

Is a sleeve like that possible? I thought cages had to be grounded to be effective?

I dunno, but my US passport card came with a foil wrapper that they recommended be left on all the time while in my wallet, so presumably they know whether it should work or not.

[Peter Todd]

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.

Is a sleeve like that possible? I thought cages had to be grounded to be effective?

Nope, but that's a very common misconception.

IAMAED (I am an electronics designer)

[Yankee (BitInstant)]

I wish I could buy some too. Before reading this thread, to me it looked more like a scam. Fancy video, not much info, tried to contact them - no reply, only a Bitcoin address to send the money. Once they show up here on the forum and give some real contact details, I might be interested to invest some real buck. Also, nodes at shopping malls is good idea, but what about other locations? Think cars (precicely trucks).

Have you read our blog? blog.bitinstant.com/blog/2012/6/19/our-discovery-in-vienna-the-bitcoin-card.html

Let me know if you change your mind after reading it 

[amencon]

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?

If the secure dedicated device is as small as a credit card, why not both?

Most people currently carry around a wallet and a cell phone, adding one extra card into a wallet isn't a very high cost to incur for the potential benefits the device could provide.

Add in low cost for the device and I can't imagine why anyone would feel there is any necessity to choose one over another.

If it's as cheap as they say I'll buy at least one even if I almost never use it.  It would be worth the ~$20 just to be able to pull it out and show people some cool future tech.

[BitPay Business Solutions]

It would be worth the ~$20 just to be able to pull it out and show people some cool future tech.

Exactly.  I expect to still use my mobile phone wallet almost all the time.  But as a showpiece of tech, this is definitely something cool to show.  I'll be getting one.

[EhVedadoOAnonimato]

Is a sleeve like that possible? I thought cages had to be grounded to be effective?

Nope, but that's a very common misconception.

IAMAED (I am an electronics designer)

I had this misconception too. So, these governments forcing their subjects to use RFID passports and ID cards are basically forcing them to give up their personal details to any random stranger with appropriate equipment that passes close by...
Isn't there anything these governments subjects may do to protect their privacy, other than not bearing such cards (what's not always an option)?

[julz]

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.

Is a sleeve like that possible? I thought cages had to be grounded to be effective?

Nope, but that's a very common misconception.

IAMAED (I am an electronics designer)

Nope a sleeve like that is not possible...?
or
Nope cages don't have to be grounded to be effective?

[EhVedadoOAnonimato]

hehe, good point julz.

[matthewh3]

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.

Is a sleeve like that possible? I thought cages had to be grounded to be effective?

Nope, but that's a very common misconception.

IAMAED (I am an electronics designer)

Nope a sleeve like that is not possible...?
or
Nope cages don't have to be grounded to be effective?

Yeah he's right a Faraday cage does have to be earthed (it's a long time since I studied ) but some kind of sleeve may be possible maybe if the sleeve had a potential difference (possibly by a solar-cell and battery) it would help to block the Tx/Rx of the card (again it's a long time since I studied). 

[rjk]

A Faraday cage only needs to be grounded when you want to use it to protect the contents from high voltage. No ground is needed for a foil wrap to reflect radio waves.

[MoonShadow]

A Faraday cage only needs to be grounded when you want to use it to protect the contents from high voltage. No ground is needed for a foil wrap to reflect radio waves.

This only works to a point.  If the frequency of the device is shorter than the resonant wavelength of the foil wrapper, it can just resonate the single right through.  Unplug your microwave, put your cell phone into it, and call your cell  phone and you will see what I mean.

[giszmo]

A Faraday cage only needs to be grounded when you want to use it to protect the contents from high voltage. No ground is needed for a foil wrap to reflect radio waves.

If I'm surrounded by metal that is hit by lightning, it doesn't matter if this metal is grounded or not as no matter which two points of my cage I touch these two points will never expose me to high voltage as the cage's resistance is by many magnitudes lower than my body's and thus the electrons would not want to flow through me but rather through the metal - grounded or not.