Instant New Way to Send Bitcoins

[jimbobway]

Right now making payments via Bitcoins is not instant since you have to wait for confirmations which could take 10 or more minutes.  You have to use a third party to transfer bitcoins, such as mybitcoins.com.

So I have an idea to transfer bitcoins instantly using the current system without using a third party.

First the bitcoin app needs to be able to support multiple wallets.  If I want to instantly send bitcoins to another user, I create wallets containing coins in certain denominations.  For instance, I have a pre-made wallet with 1 coin in it.  If I want to pay someone, I send him my ENTIRE wallet.

This way I can go to anyone with a phone or a store and pay him instantly by handing the wallet without waiting for confirmations.

Summary: Ability to have multiple wallets and ease of use.  What do you guys think?  Maybe we can explore this idea?

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[davout]

how would you prevent double spending ?

[jimbobway]

how would you prevent double spending ?

Doh!  My idea is screwed.

[grondilu]

lol


if it was that easy to transfer money, we wouldn't need bitcoin at all

[jimbobway]

I would delete this thread if I could.

[davout]

just let me screencap it before XD

[ribuck]

It would be a good way to transfer coins between friends where trust already exists, and where there is no need to write the transaction to the block chain. It may also have some application to sending coins over ad-hoc networks where the block chain is unavailable.

[davout]

It would be a good way to transfer coins between friends where trust already exists, and where there is no need to write the transaction to the block chain. It may also have some application to sending coins over ad-hoc networks where the block chain is unavailable.

A cleaner way could then be to send someone an already signed transaction that would just be broadcast whenever the bitcoin network becomes reachable. Well, it doesn't solve the double spending problem much better acutally. But I mean in the friends use case, why not simply promise the coins and transfer them once the network is available ?

jimbobway, your solution makes sense for small amounts where there is some level of trust (I'd rather not be expected with a shotgun next time I go buy cigarettes), but there would then be the problem of employees being able to easily steal from the shop by simply copying a file.

[jgarzik]

Handing out wallet.dat files is just fine.  I think it's a great idea.

Sure, there is the possibility of double-spending...  but only by the person handing out the wallets.  Presumably, you trust yourself

[jimbobway]

My idea kind of resembles a gift card.  A gift card has a credit card number which the giver can write down.  He doesn't though, so he gives it to gift card receiver who is free to use that gift card.  In this case there is a lot of trust.

On a similar note watch out for gift card scams where people go to the store, write down the gift card number, and wait for it to be loaded.  They will check for loaded gift cards, and once they contain money they will spend it!

[mndrix]

Right now making payments via Bitcoins is not instant since you have to wait for confirmations which could take 10 or more minutes.  You have to use a third party to transfer bitcoins, such as mybitcoins.com.

You don't have to wait for confirmations.  For small transfers, your probable loss from a double-spend is so small that you can accept a valid bitcoin transaction as payment; assuming the transaction will eventually be incorporated into the block chain.  Your definition of "small" depends on how much risk you're willing to accept.

Most large USD transactions I've been involved with take longer than 10 minutes just for the paperwork.  If Bitcoin payment was made up front, one could be signing paperwork while the confirmation blocks arrived.

[jimbobway]

Handing out wallet.dat files is just fine.  I think it's a great idea.

Sure, there is the possibility of double-spending...  but only by the person handing out the wallets.  Presumably, you trust yourself

Yes, if you trust yourself, which obviously we most likely do, and have a really good reputation where users trust the giver, then this would work.  I guess it all boils down to trust.

[Mike Hearn]

Yeah, exactly. Once a transaction appears as 0/unconfirmed, what that actually means is that the payment is valid (as in, is spending existing coins that have not already been double spent) and it's just waiting for the network to generate a block with that transaction in.

Causing problems once a valid transaction is broadcast is a pretty difficult attack.

[teknohog]

Handing out wallet.dat files is just fine.  I think it's a great idea.

Sure, there is the possibility of double-spending...  but only by the person handing out the wallets.  Presumably, you trust yourself

So double spending is possible in general? I can just make 10 copies of my wallet, and buy something worth 10 times my balance?

[MoonShadow]

Handing out wallet.dat files is just fine.  I think it's a great idea.

Sure, there is the possibility of double-spending...  but only by the person handing out the wallets.  Presumably, you trust yourself

So double spending is possible in general? I can just make 10 copies of my wallet, and buy something worth 10 times my balance?

Define possible.  Probably not on any realistic level.  The conditions required are pretty narrow.

[jgarzik]

So double spending is possible in general? I can just make 10 copies of my wallet, and buy something worth 10 times my balance?

In general it is not possible.  P2P nodes won't accept a double-spend, making it very difficult.  See the snack machine thread for interesting reading.

[davout]

When I mentioned double spends in my first post I was merely speaking about the following case :
 - I buy an item giving a copy of my wallet (first spend)
 - I spend the coins contained in the original before the payee does (second spend)

[Gavin Andresen]

I think of this as a subset of the "I want to move N bitcoins from my wallet to a USB stick that I'll put in my safe deposit box so it cannot be hacked", "bitcoins as a long-term store of value" feature:
  https://github.com/bitcoin/bitcoin/issues#issue/2

A solution should:
 + Make accidental double-spending impossible (or at least, very hard)
 + Remove the private keys from your wallet so if the wallet is stolen they coins are safe
 + Be as close to 100% safe as possible, even if your computer gets hit by lightning at exactly the wrong time.

That last one is the tricky bit.