It's not possible when it has at least one confirmation your money is fully gone, ...
false.
please read previous posts on this thread to get some hints on why it's possible.
Topic: Has anyone ever cancelled a BTC transaction after 1 confirmation? (Read 2425 times)
false.
please read previous posts on this thread to get some hints on why it's possible.
April 24, 2014, 11:21:43 AM
It's not possible when it has at least one confirmation your money is fully gone, if it doesn't get any confirmations for a long time i think It would get back to your wallet, at least someone said that to me.
April 24, 2014, 11:17:01 AM
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 Thanks in advance
We now have miners with hundreds of thousands of dollars of equipment which run it off a raspberry pi. Who send their coins directly to coinbase to be sold. Who have never used a Bitcoin client of any kind (except for the coinbase webwallet), certainly not a full node, and they have no concept of why they'd want to. The name they trust most in mining is operator of their chosen pool— who could be robbing them blind, but maybe isn't— who has a financial interest to the tune of— say— >$700,000/month in keeping miners on their pool, and who tells them they don't need to worry about things, and who is believed because far too many people— including you— overly fixate on "51%" and ignore the fact that someone who controls 25% hashpower can reorg 6 confirms with 5% success or 2 with 31% success.
bold is mine
April 24, 2014, 11:11:31 AM
How do I vouch for a Bitcoin expert badge (https://bitcointalksearch.org/topic/m.4233210) for Danny?
You don't. Only a core developer or other "Bitcoin Expert" is allowed to recommend that someone receive the "Bitcoin Expert" badge.
I have seen multiple times that Danny is a true expert of the Bitcoin protocol. So, I guess, he deserves the title.
Titles don't mean much to me. My advice and assistance stand on their own merits.
April 24, 2014, 09:35:15 AM
Is this even possible?
Thanks in advance
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.
How do I vouch for a Bitcoin expert badge (https://bitcointalksearch.org/topic/m.4233210) for Danny ? I have seen multiple times that Danny is a true expert of the Bitcoin protocol. So, I guess, he deserves the title.
April 24, 2014, 09:28:29 AM
Is this even possible?
Thanks in advance
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.
You know,there's already a service which offers such a thing for transactions with 0 confirmations. I'm not sure about the one with 1 confirmation as it would be a lot harder,but yes,the possibility is almost 0.
April 24, 2014, 09:25:37 AM
virtually impossible, same concept as double spending
Yet it is possible. Please do more research or just read the damn replies in the thread! 
April 24, 2014, 05:49:51 AM
You can't even cancel a BTC transaction after ZERO confirmations.
April 24, 2014, 05:04:54 AM
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 Thanks in advance
Not exactly true. If it is confirmed, but that block is part of a fork and the competing block wins, then it will become "unconfirmed" *if* it doesn't also appear in the competing fork.
April 24, 2014, 04:24:47 AM
"Event can occur, but with 0 probability", - my lecturer in probability theory said )
April 24, 2014, 02:42:39 AM
virtually impossible, same concept as double spending
April 24, 2014, 01:13:00 AM
I dont think its possible unless with miners thats why they cant spend mined blocks for 100blocks
April 23, 2014, 09:39:00 PM
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.
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.
April 23, 2014, 03:03:08 PM
Is this even possible?
Thanks in advance
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.
April 23, 2014, 02:46:14 PM
it's like reverse killing a man. impossible
April 23, 2014, 01:40:56 PM
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"
"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"
April 23, 2014, 01:39:19 PM
Yes but that case was different. (Fork)
A successful DOUBLE SPEND US$10000 against OKPAY this morning.
https://bitcointalksearch.org/topic/a-successful-double-spend-us10000-against-okpay-this-morning-152348
A successful DOUBLE SPEND US$10000 against OKPAY this morning.
https://bitcointalksearch.org/topic/a-successful-double-spend-us10000-against-okpay-this-morning-152348
And the story has a happy ending. OP of that thread sent the bitcoin back to OKPay.
April 23, 2014, 01:33:10 PM
Yes but that case was different. (Fork)
A successful DOUBLE SPEND US$10000 against OKPAY this morning.
https://bitcointalksearch.org/topic/a-successful-double-spend-us10000-against-okpay-this-morning-152348
A successful DOUBLE SPEND US$10000 against OKPAY this morning.
https://bitcointalksearch.org/topic/a-successful-double-spend-us10000-against-okpay-this-morning-152348
April 23, 2014, 01:31:39 PM
Nice one brother, that's what I thought.
There's another post regarding "how bitcoins are too slow" - This being a non-issue then
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.
April 23, 2014, 01:31:24 PM
Is this even possible?
Thanks in advance
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
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