Single-Address Hardware Wallet

[btcspry]

Would anyone here buy a disposable hardware wallet that is programmed ONCE, and then cannot be programmed with a different private key.  Instead, you just toss it and buy a new one if you want a different address.  It would only have a single address, but I could still see this having some use.

It would only cost maybe $5 per wallet, so you could have 5 of them for pretty cheap, and then just get a new one if you need a new address (they wouldn't be HD, obviously).  It would be like the old paper wallets, but way easier and more secure to spend from.  Would anyone buy it?

The idea is that it would be really cheap and secure, and the address on it cannot be faked or anything.  Obviously it would be open source.  If anybody thinks it's a good idea, maybe we could start a development team (and a Kickstarter) eventually.  Lemme know what everyone thinks.

[olliec420]

Would be worth looking at for sure!

Instead of carrying a brief case of cash to meetings, this one use device would work nicely!

[btcspry]

Would be worth looking at for sure!

Instead of carrying a brief case of cash to meetings, this one use device would work nicely!

Thanks for the response, that was our thought too!

[PolarPoint]

It would be useful as a "forwarding address". People can send coins to that address and the owner can forward the coins to another address he owns. If it is designed to be disposable, it still need to look chic and be durable. 

[btcspry]

It would be useful as a "forwarding address". People can send coins to that address and the owner can forward the coins to another address he owns. If it is designed to be disposable, it still need to look chic and be durable. 

Well of course, it would be the sexiest bitcoin device ever!

That's actually a great theoretical application, makes sense.

[inaltoasinistra]

Why limit it to only one address? The cost of implementing more addresses is negligible, the hardware is the same (if it can sign transactions it can store some keys). Am I wrong?

[BG4]

NFC tags make great cheap single address wallets....Is this on the lines you are thinking about..?

[btcspry]

Why limit it to only one address? The cost of implementing more addresses is negligible, the hardware is the same (if it can sign transactions it can store some keys). Am I wrong?

The idea is to be unique and simple.  There's already so many HD wallets that have all the features.  We wanted to create something super simple that can be easily managed, that's smaller, and that doesn't have a screen (we are looking at using a single blinking LED to communicate with the customer, although the details still haven't been worked out).

[btcspry]

NFC tags make great cheap single address wallets....Is this on the lines you are thinking about..?

The idea is to make it way more secure.  It would be like a Trezor, where you can't get the private key off of the device.  You could use it as a temporary wallet if you need to carry around 100 BTC in your back pocket for a day or two.  It cannot be hacked, it would be small enough to hide, and you can send from it easily (without requiring a USB stick and an offline computer [like you would with a paper wallet]).  NFC is too insecure, so we would just use a USB connection for data transfer though.

[btchip]

The idea is to make it way more secure.

Why is NFC insecure ? it's just a transport mechanism.

Also secure, open source, < $5, I know how to pick 2 of 3, so I'd be interested to learn more about the design

[BG4]

NFC tags make great cheap single address wallets....Is this on the lines you are thinking about..?

The idea is to make it way more secure.  It would be like a Trezor, where you can't get the private key off of the device.  You could use it as a temporary wallet if you need to carry around 100 BTC in your back pocket for a day or two.  It cannot be hacked, it would be small enough to hide, and you can send from it easily (without requiring a USB stick and an offline computer [like you would with a paper wallet]).  NFC is too insecure, so we would just use a USB connection for data transfer though.

There are tags capible of having password protected areas.... I use a nfc tag for access to my greenaddress app.. which is password protected...That makes NFC tags little HD wallets.....you should not overlook the ability of a simple , cheap NFC tag...  The NXP ntag216 is able to store 888 bytes of data....  also BitNFC  has a cool open source wallet with NFC tag  bitcoin transfer....

[btcspry]

NFC tags make great cheap single address wallets....Is this on the lines you are thinking about..?

The idea is to make it way more secure.  It would be like a Trezor, where you can't get the private key off of the device.  You could use it as a temporary wallet if you need to carry around 100 BTC in your back pocket for a day or two.  It cannot be hacked, it would be small enough to hide, and you can send from it easily (without requiring a USB stick and an offline computer [like you would with a paper wallet]).  NFC is too insecure, so we would just use a USB connection for data transfer though.

There are tags capible of having password protected areas.... I use a nfc tag for access to my greenaddress app.. which is password protected...That makes NFC tags little HD wallets.....you should not overlook the ability of a simple , cheap NFC tag...  The NXP ntag216 is able to store 888 bytes of data....  also BitNFC  has a cool open source wallet with NFC tag  bitcoin transfer....

Does the tag sign the transaction on the tag itself?  If not, then it's not as secure as this.

[BG4]

NFC tags make great cheap single address wallets....Is this on the lines you are thinking about..?

The idea is to make it way more secure.  It would be like a Trezor, where you can't get the private key off of the device.  You could use it as a temporary wallet if you need to carry around 100 BTC in your back pocket for a day or two.  It cannot be hacked, it would be small enough to hide, and you can send from it easily (without requiring a USB stick and an offline computer [like you would with a paper wallet]).  NFC is too insecure, so we would just use a USB connection for data transfer though.

There are tags capible of having password protected areas.... I use a nfc tag for access to my greenaddress app.. which is password protected...That makes NFC tags little HD wallets.....you should not overlook the ability of a simple , cheap NFC tag...  The NXP ntag216 is able to store 888 bytes of data....  also BitNFC  has a cool open source wallet with NFC tag  bitcoin transfer....

Does the tag sign the transaction on the tag itself?  If not, then it's not as secure as this.

I am curious now to what hardware you had in mind that was cheap, disposable, and able to sign transactions...  The only off the shelf boards that I know of for prototyping, that are really cheap would be an arduino pro micro ......Is this what you are going for??

http://www.ebay.com/itm/Pro-Micro-Atmega-32U4-MU-5V-16MHz-Board-Module-For-Arduino-Compatible-/231451407743?pt=LH_DefaultDomain_0&hash=item35e394357f

[btcspry]

No, I'm not going to write a program for an Arudino...that's kind of insulting that you think it's what we had in mind.

We would likely use a similar chips compared to what's on an Arduino (only because they're very popular).  We would design a very simple board with 1 or 2 GPIO pins (not the 13+ that Arduino have to offer), and we'd include a single-time programmable chip (the details of which we haven't worked out yet) that would allow the device to only be written to once.  We would encase the whole thing in 1/8" plate steal (folded) to ensure it's difficult to get in (maybe, again that's just an idea).

We don't really have many intentions of working on this right away, it's just an idea.

[bitnanigans]

Wouldn't this be a waste of physical resources? Unless the wallets are made of biodegradable materials, why not just stick with software?

[btcspry]

Wouldn't this be a waste of physical resources? Unless the wallets are made of biodegradable materials, why not just stick with software?

Simplicity and cheapness, also as a business model it's pretty great.  Chips are so cheap that it's not a big deal.  Also, security because you can't accidentally erase it, and someone can't load another address onto your device (which could be an issue).  Just some thoughts though.

[noel57]

I think this will be more secure since the address is single and cannot be faked but what I am thinking of is the cost of shipping to individual country, how can someone use 15$ to ship in $5 worth of item, this might be better if it is a software.

[btcspry]

I think this will be more secure since the address is single and cannot be faked but what I am thinking of is the cost of shipping to individual country, how can someone use 15$ to ship in $5 worth of item, this might be better if it is a software.

I order $1 things on eBay all the time - some of that goes to shipping.

The idea is that you'd order 10 of them for different times and whatnot.  $5 shipping, shipping is less than 10% of the cost.  They'd be so small that it wouldn't be an issue, just a little bubble-wrap packed envelope would be perfect.

[PolarPoint]

I hear a lot of people are doubting the use of a physical disposable hardware wallet. If the price is cheap enough, there are many good uses for them.

Forwarding address is one use for them. Loading them and giving them out as gifts to non bitcoin users would be another obvious use. Use them to replace paper wallet cold storage could be another. Users could store small amounts on many of them to "spread" the risk of hardware failure.

There are even uses for these wallets if the private key is not known to anyone including the manufacturer, the owner, and the user. There will be no risk of leaked keys, or multiple people controlling the same address, the bearer of the device is the only one controlling the funds in the address. Lawyers and escrows could use a device such as this.

[btcspry]

I really like the last post explaining possible applications.  Those are the major things we've thought of (plus some) in terms of what this could be used for.

We hadn't really considered the applications that involve nobody knowing the private key.  We could maybe sell two version - one that releases the private key at the beginning, and one that makes it so that nobody knows the key (for the gift example like you mentioned).