Bitcoin double spend | Bitcointalksearch.org

pooya87

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Quote from: BlackHatCoiner on May 29, 2021, 12:23:57 AM

I think that when the developers started implementing RBF, they used a very misleading word as a verb to this procedure. Double spending is prevented using a peer-to-peer network as the whitepaper says, but they chose that phrase as the proper one for RBF. Maybe a better formulation would be re-broadcasting or broadplacing?

The term used to describe RBF transaction is a correct term and not at all misleading. Double spending in bitcoin simply means spending the same transaction output more than once in different transactions. The term itself doesn't have any indication of success of the act.
1. You can double spend outputs in an already confirmed transaction
2. You can double spend outputs in an unconfirmed transaction without RBF
3. You can double spend outputs in an unconfirmed transaction with RBF
#1 is obviously rejected by all full nodes because it is invalid. #2 is rejected by most full nodes because it is non-standard and #3 is accepted by most full nodes because it is optional.

o_e_l_e_o

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Quote from: hosseinimr93 on May 31, 2021, 01:32:30 PM

Once you use RBF feature and replace the original transaction with a new one, the original transaction and all its children become invalid and you no longer need to worry about the transaction made for implementing CPFP.

That's not strictly true. The transaction which is being replaced, and any children based on that transaction, only become invalid when the RBF transaction confirms and the inputs the original transaction uses are no longer available. Until the RBF transaction confirms, the original transaction and its children are still perfectly valid. Now, most mempools will eject them in favor of the RBF transaction, but that doesn't make them invalid, and any node or miner could still choose to mine them over the RBF transaction.

There are other ways an attacker could guarantee their CPFP confirms instead of your RBF, such as by using transaction pinning to make the RBF fee you would have to pay prohibitively large, or by creating and broadcasting enough child transactions to prevent RBF from occurring, as per rule 5 of BIP 125.

hosseinimr93

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Quote from: khaled0111 on May 29, 2021, 02:03:42 PM

there is always a possibility to lose your money if the receiver spends the unconfirmed transaction and his cpfp transaction gets confirmed before the rbf transaction.

It's not possible.
Once you use RBF feature and replace the original transaction with a new one, the original transaction and all its children become invalid and you no longer need to worry about the transaction made for implementing CPFP.

I agree that no one should use this service, off course.

khaled0111

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Quote from: franky1 on May 29, 2021, 05:29:01 AM

it asking you to fund them first .. where they then perform the double spend for you.. well thats iffy at best. you have to trust they will. and from the look of the site seems dodgy.

You have to send them the amount you want to double spend plus their fee (4.9%) which is rediculous since you can do it for free with any wallet that supports rbf.
Although they give you the private key for the address you have to fund, it's still risky as they can sweep it anytime they want.
Even if they are not going to scam, there is always a possibility to lose your money if the receiver spends the unconfirmed transaction and his cpfp transaction gets confirmed before the rbf transaction.

In any case, don't use this service!

franky1

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double spend is not actually blockchain confirmed double spend

it can only happen if you find an idiot service that accepts payment without confirmation..
its like double-chequing
having only $50 in your account but writing 2 cheques for $50 each..
only one will clear. but by the time its cleared and one loser finds out. you have walked away with the goods from both services

..
however this topics question is if the service he linked is a scam of itself.. and from my view. it asking you to fund them first .. where they then perform the double spend for you.. well thats iffy at best. you have to trust they will. and from the look of the site seems dodgy.

ranochigo

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Quote from: BlackHatCoiner on May 29, 2021, 12:23:57 AM

I think that when the developers started implementing RBF, they used a very misleading word as a verb to this procedure. Double spending is prevented using a peer-to-peer network as the whitepaper says, but they chose that phrase as the proper one for RBF. Maybe a better formulation would be re-broadcasting or broadplacing?

Double spending is impossible in Bitcoin if and only if you're looking at the blockchain alone; a single chain cannot have two of the same inputs being spent twice. You can however, choose to spend an input that has been spent before and is currently in the mempool. Technically, by being able to broadcast a transaction which spends the same inputs as another in the mempool is regarded as double spending it, though obviously the other gets kicked out.

This is not an accelerator as some of the users here are claiming. This is a site to broadcast two competing transactions by broadcasting a conflicting transaction after the other. This site isn't intended to help users to use RBF to unstuck your transaction but rather to help users intentionally replace a current transaction with their own. You can do so with any wallet that support RBF.

Blowon

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I don't understand about this double bitcoin run-out. But reading the site, you can buy things without losing your bitcoin. Do you have to send fake bitcoins to the target address and then the actual bitcoins will come back to you? It looks like a scam.

franky1

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RBF is a bitcoin feature

but if someone else is doing RBF on your behalf. hey have to have the coins to do it
meaning you give them the coin in the first place with you having to trust that they are going to broadcast back to you later.

the trick is not RBF. the trick is you 'fund payment' them first

when you realise the game is not about presenting the seashells. and is about your money is gone as soon as you put it on the table. .. you lost before you even get to see the seashells move

so do RBF yourself . dont fund someone elses scheme

BlackHatCoiner

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Quote from: Lora Grahem on May 28, 2021, 05:16:23 PM

Hi guys I'm trying to use this site bitcoindoublespend.info to double spend btc anyone use this site before is this trust

I think that when the developers started implementing RBF, they used a very misleading word as a verb to this procedure. Double spending is prevented using a peer-to-peer network as the whitepaper says, but they chose that phrase as the proper one for RBF. Maybe a better formulation would be re-broadcasting or broadplacing?

Anyway, in Bitcoin you can't double-spend. You may be able to increase the fee by re-broadcasting your transaction, but that won't mean that you double-spent it.

As for the site, it seems way too suspicious. Try electrum as Charles-Tim mentioned.

Quote from: Coin_trader on May 28, 2021, 05:32:20 PM

This is a shady website as well as there service offer. First of all, What is your reason for using this kind of service?

I agree that it looks shady, but RBF isn't a scam and it's different than accelerating a transaction. It's more practical to pay for a higher fee than forcing a service to accelerate your transaction.

FinneysTrueVision

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On the manual page it says they are just using RBF to replace an unconfirmed transaction. It is much more simpler to just do this yourself without having to pay a fee to some shady website. Electrum already has an option to cancel a transaction and send the unconfirmed coins back to yourself.

franky1

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shady website offering a service to scam.. usually ends up with you being scammed
oopsie you deposited funds but the scamsite double spend on you.. you aint getting coins back

whats next.
stand on a street corner playing the 3 seashell trick with a hustler
put your money under the shell.. if you can guess which shell the money is under you get it back.. oops you lost
(heres the secret. hustler pocketed the money when putting the shell on the table.. no shell has the money)

Lora Grahem

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Thanks bro for all information i think electrum is the best choice for replace by fee thx for help me

Charles-Tim

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Quote from: Coin_trader on May 28, 2021, 05:32:20 PM

Stay away on that services. If you want boost your unconfirmed transaction. Its better to use TX accelerator services like viabtc. https://www.viabtc.com/tools/txaccelerator

Any Bitcoin transaction with less than 10 sat/byte (not sat/vbyte) can not be freely accelerated by ViaBTC acceleratator, the paid one may become the only choice at times, and of which not also recommended because of high fee that will be demanded by the paid accelerator.

It is better to use electrum, making sure the transaction support replace-by-fee, even if the transaction has a very low fee, it can easily be pumped to any higher fee amount. Pumping the fee is the best choice, but a transaction that does not support replace-by-fee can not be easily pumped, the sender may not even have choice than to wait for it to be confirmed which might take days or weeks or even more months.

Coin_trader

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Quote from: Lora Grahem on May 28, 2021, 05:16:23 PM

Hi guys I'm trying to use this site bitcoindoublespend.info to double spend btc anyone use this site before is this trust
I am looking to your answers.
Thanks

This is a shady website as well as there service offer. First of all, What is your reason for using this kind of service? There tool is for scamming people and I don't know if double spending is still possible on the current code of Bitcoin.

Stay away on that services. If you want boost your unconfirmed transaction. Its better to use TX accelerator services like viabtc. https://www.viabtc.com/tools/txaccelerator

Charles-Tim

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The mistake of most people is that they are not using Bitcoin wallet that can double-spend. If you want to be able to double-spend unconfirmed Bitcoin in a transaction, all you need to do is to make use of electrum wallet. You can use this guild to know how you can download electrum from https://electrum.org and verify its signature.

On electrum wallet, you can create a transaction that support replace-by-fee, if you send Bitcoin to an address, and not yet confirmed, if the transaction support replace-by-fee, you can double-spend the Bitcoin into another address with high fee. But know that if the Bitcoin transaction has been confirmed, it can not be double-spent again, only unconfirmed Bitcoin transaction can be double-spent with higher fee into another address or cancelled in a way it will be sent back into another address on your elecrum wallet.

Lora Grahem

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Hi guys I'm trying to use this site bitcoindoublespend.info to double spend btc anyone use this site before is this trust
I am looking to your answers.
Thanks

Topic: Bitcoin double spend (Read 268 times)