Has anyone ever cancelled a BTC transaction after 1 confirmation?

[RockHound]

Is this even possible?

Thanks in advance  

[cooldgamer]

Is this even possible?

Thanks in advance 

Not possible, once it's confirmed it's in the blockchain forever.  That's the beauty of Bitcoin

[RockHound]

Nice one brother, that's what I thought.

There's another post regarding "how bitcoins are too slow" - This being a non-issue then

[Meuh6879]

even if you shutdown the client ... when you emit transaction, it's spread from 6 to 9 node at the same instant.
you can't stop the network even with 0 confirmation.

1 confirmation append from 15mins to 40mins.

yes; it's the beauty of a strong and unstoppable working network over the world (and behind ?).

[RockHound]

Nice one brother, that's what I thought.

There's another post regarding "how bitcoins are too slow" - This being a non-issue then

Many bitcoiners on here are frustrated with the #/time (confirmations) required from 3rd party bitcoin services.

As a business idea, could someone (probably me : )  offer a service where client inputs their transaction ID, sign the funds/xBTC over to me, then I instantly back them up for xBTC so that they can spend straight away?

[TrailingComet]

Not possible, can't be done

[DannyHamilton]

Is this even possible?

Thanks in advance  

It is possible, but it is difficult, expensive, and unreliable.

If you have enough hashpower, you could create a transaction that spends some bitcoins to another address that you own, and not broadcast that transaction.

Then you could mine a block with that transaction on top of the current blockchain.

As soon as you successfully mine a block, you could broadcast a different transaction that spends the same inputs sending the bitcoins to a merchant, and NOT broadcast the block you just solved.

While the network is working on confirming your transaction into a block that will compete with your block, you continue mining on top of your block.

Eventually, the network will solve a block with your transaction in it and the merchant will see 1 confirmation. You continue to mine on top of your block instead of on top of the network's block.

If you have enough hash power and are lucky enough to mine another block before the rest of the network does, you broadcast your two blocks.

There are other possible attacks as well, but none of them are cheap, easy, and 100% reliable.

Since your two blocks create a longer blockchain than the current blockchain that has only added one block, the entire network switches to your blockchain and the 1 confirmation transaction to the merchant disappears (since it competes with your first transaction that now has 2 confirmations).

The more confirmations you have, the more difficult, expensive, and unreliable an attack like this is.

[RockHound]

Cheers Dr Danny,

Interesting scenario there! But won't they have different txid's?

My proposed model for instant spendable BTC, would require enormous trust in it's clients. Would have to trust exact funds are transferred after our client receives full confirmations.

So to recap,  bitcoiners cannot spend their BTC until their 3rd party service allows? Even if they see the funds are incoming? WTF  given after 1st confirmation it can't be reversed (or very expensive, to do so)

Why can't we request redirection after 1 confirmation i.e as soon as fully confirmed it automatically goes to specified redirect address?

[DannyHamilton]

Cheers Dr Danny,

Interesting scenario there! But won't they have different txid's?

Absolutely.  How does this effect the original question?

My proposed model for instant spendable BTC, would require enormous trust in it's clients. Would have to trust exact funds are transferred after our client receives full confirmations.

I didn't see anything about a proposed model for anything.  I just saw a question about cancelling a BTC transaction after 1 confirmation.

So to recap,  bitcoiners cannot spend their BTC until their 3rd party service allows?

What 3rd party service are you asking about?

Even if they see the funds are incoming?

What do you mean by "see the funds incoming"?

WTF  given after 1st confirmation it can't be reversed (or very expensive, to do so)

Each receiver sets their own requirements of payment.

Why can't we request redirection after 1 confirmation i.e as soon as fully confirmed it automatically goes to specified redirect address?

Redirect address?  I don't understand how this relates to the question in this thread.

[sgbett]

Is this even possible?

Thanks in advance  

mostly, you don't even need 1 confirmation...

http://www.cryptocoinsnews.com/news/the-mathematically-secure-way-to-accept-zero-confirmation-transactions/2014/02/13

[RockHound]

Nice one brother, that's what I thought.

There's another post regarding "how bitcoins are too slow" - This being a non-issue then

Many bitcoiners on here are frustrated with the #/time (confirmations) required from 3rd party bitcoin services.

As a business idea, could someone (probably me : )  offer a service where client inputs their transaction ID, sign the funds/xBTC over to me, then I instantly back them up for xBTC so that they can spend straight away?

Cheers Dan, here's the rough model. I posted as a response to this thread.

[escrow.ms]

Yes but that case was different. (Fork)
A successful DOUBLE SPEND US$10000 against OKPAY this morning.
https://bitcointalk.org/index.php?topic=152348.0

[Yuki1988]

Yes but that case was different. (Fork)
A successful DOUBLE SPEND US$10000 against OKPAY this morning.
https://bitcointalk.org/index.php?topic=152348.0

And the story has a happy ending. OP of that thread sent the bitcoin back to OKPay.

[RockHound]

Nice one Escrow - that's a really interesting thread, however I think Franky1 explained this well:

"technically its not a double spend.. there is only one "receipt" of BTC that got confirmed on this main blockchain, meaning there is not 2 bunches of bitcoins that originated from one single bitcoin source on this main blockchain.

what happened is that businesses did not update the clients to be using the correct blockchain. thus the business does not see the correct transaction and ends out paying FIAT twice.

what needs to be done is to ensure forks dont happen, and in the small chance that a fork does occur, that businesses are not lazy about updating their clients, or double checking transactions before releasing different forms of funds or goods. (which would have prevented malleability issues if businesses had proper double checking methods in place)

there is not one single extra bitcoin on the blockchain that was cloned or not originate from a verified block reward. ill say it again a double spend is where 1 btc can be used twice. no coin has been used twice. all that has happened is that businesses have not had adequate checking processes in place. the bitcoin protocol and the blockchain does not show more confirmed coins then what has been released through blockchain rewards"

[Bitcoin Magazine]

it's like reverse killing a man.  impossible

[Lauda]

Is this even possible?

Thanks in advance  

It is possible, but it is difficult, expensive, and unreliable.

If you have enough hashpower, you could create a transaction that spends some bitcoins to another address that you own, and not broadcast that transaction.

Then you could mine a block with that transaction on top of the current blockchain.

As soon as you successfully mine a block, you could broadcast a different transaction that spends the same inputs sending the bitcoins to a merchant, and NOT broadcast the block you just solved.

While the network is working on confirming your transaction into a block that will compete with your block, you continue mining on top of your block.

Eventually, the network will solve a block with your transaction in it and the merchant will see 1 confirmation. You continue to mine on top of your block instead of on top of the network's block.

If you have enough hash power and are lucky enough to mine another block before the rest of the network does, you broadcast your two blocks.

There are other possible attacks as well, but none of them are cheap, easy, and 100% reliable.

Since your two blocks create a longer blockchain than the current blockchain that has only added one block, the entire network switches to your blockchain and the 1 confirmation transaction to the merchant disappears (since it competes with your first transaction that now has 2 confirmations).

The more confirmations you have, the more difficult, expensive, and unreliable an attack like this is.

Your knowledge always seems to amaze me. This is a bit complicated to do, and not worth it like you just said.

[Syke]

Any time a block is orphaned, there is a (very small) chance a transaction from the orphaned block won't get confirmed in the new chain. Typically there are about 2 orphans per day:

https://blockchain.info/charts/n-orphaned-blocks?timespan=30days&showDataPoints=false&daysAverageString=1&show_header=true&scale=0&address=

A single confirmation is by no means a guarantee that the transaction will stay valid. That is why the normal bitcoin client shows transactions as "unconfirmed" until there are 6 confirmations.

[activebiz]

I dont think its possible unless with miners thats why they cant spend mined blocks for 100blocks

[vnvizow]

virtually impossible, same concept as double spending

[omgeak]

"Event can occur, but with 0 probability", - my lecturer in probability theory said  )