Questions tagged [doublespend]
This tag should be used for questions related to double spending. Double spends are when a money is spent more than one time. This is considered a form of fraud.
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What is a Finney attack?
What is a Finney attack? Extra points for explaining its purpose, the prerequisites for it to be possible, how the attack can be performed and the origin of the name "Finney attack".
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What is a double spend?
What is a double spend?
As someone who uses Bitcoin, what do I need to know about how the Bitcoin system prevents double spends? Are there still circumstances where they can occur?
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Can bitcoins be counterfeited?
Traditional currencies have anti-counterfeiting features designed to make them hard to copy, but despite this attempt counterfeit money is a real threat. Since bitcoins are digital, it's trivial to ...
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How does Ripple solve the double-spend problem?
How does the Ripple system solve the double-spend problem? Does it also use some block-chain-like entity that officially dictates which transactions are confirmed and which are not, or does it use ...
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Would a reduced block generation time make the Finney attack more difficult?
Related Question:
What can be done to mitigate the risk of a Finney attack?
The Finney attack is a form of double-spending attack where the attacker pre-mines a block containing a conflicting ...
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How do I detect a double-spend?
As a vendor, how do you detect a double-spend? I'm happy to tell end-users that I'm proceeding with a transaction on 0 confirms, simply assuming everything is fine. I'm selling physical goods and so I ...
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Has there ever been a successful double spend attack on the Bitcoin network? If not, is it really necessary to wait for confirmations?
There is a lot of concern about waiting for confirmations to avoid a double spend attack, but has there ever actually been a double spend attack?
It seems to be that there are two types of double ...
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What does the Bitcoin client do when it receives conflicting transactions?
I've been assuming that the second transaction will simply be discarded as invalid, while the first waits at 0/unconfirmed until it actually gets into a block (requiring a "-rescan" or similar if the ...
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What is the best way to recover from an accidental double-spend?
Came across an issue where I was given the message:
"Error: The transaction was rejected. This might happen if some of the coins in your wallet were already spent, such as if you used a copy of ...
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How is a Transaction Output Marked as Spent?
The Bitcoin developer guide states that
each output of a particular transaction can only be used as an input once in the block chain. Any subsequent reference is a forbidden double spend—an ...
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In a double spend attempt, how is the valid transaction chosen?
Suppose I publish the private key of an address that contains 1 bitcoin. If two people try to transfer this bitcoin to another address before a new block is found, who gets it? How is this decision ...
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Could any standard fee transaction be double spent by using a higher fee?
I realize that if somebody makes a transaction without any fees and there have not yet been any confirmations, then the transaction could be double spent by just spending the same inputs to a ...
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Understanding a Bitcoin Double Spending Transaction by Performing one on yourself
Everyone talks about preventing a double spend transaction, but how does one do one to yourself in order to better understand the steps involved by the attacker?
What is required to do a double spend?...
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JSON-RPC to detect double-spent TXs
How can I be positive that one of the incoming payments to my bitcoin-core was double-spent after it was confirmed once by the network, through the JSON-RPC interface?
Related questions:
How do I ...
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double spending
I do understand the necessity for a proof of work to avoid malicious miners mining a fork on the current blockchain.
This is difficult as this proof of work takes lots of power (and time).
Yet I don'...
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Is there a risk of double-spending when making a face-to-face transaction?
When exchanging funds or services face-to-face, is there a risk of a double-spending attack? If there is, how could it be technically done?
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What are the pros and cons of Ripple's consensus as compared with Bitcoin's proof-of-work?
One of the major differences between Bitcoin and Ripple is how they process transactions. I can think of three ways in which Ripple's "consensus" scheme is superior to Bitcoin's proof-of-work:
Less ...
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Are there alternatives for proof of work?
Bitcoin uses proof of work to secure the network, Ripple uses a global consensus system and PPCoin uses proof of stake.
Are there any known alternatives to the above methods?
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Bitcoin without mining
Several months ago I've stumbled an interesting question about the Ripple system: How does Ripple solve the double-spend problem?
Specifically about how double-spending is solved in Ripple. As you ...
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Double spend attack by sending higher fee transaction directly to the pools possible?
The standard client prioritizes TXs by the time of receipt, e.g. a conflicting transaction will not be relayed. This is not enforced by the network, though. Is there anything that would prevent this ...
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How do people actually try double-spends?
I've occasionally seen people online claiming they were victims of a double-spend because they handed over something of value in exchange for a bitcoin payment with no confirmations.
Although I ...
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Speeding up confirmation by double-spending a transaction stuck in mempool
In the context of no-fee transactions that can take a long time to get their first confirmation, is it possible to use raw transactions and double-spend the original transaction by broadcasting ...
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Is there any software available for testing of Bitcoin security?
I'm currently in the process of working on my thesis about Bitcoin security and I'm wondering if there's any software available for testing of Bitcoin security? For example, are there any programs ...
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Double Spending - Does each node maintain a list of unspent transaction references?
My Understanding Of How Bitcoin Prevents Double Spending
Each transaction contains references to the input transactions and ever node has to verify all transactions from time immemorial to ensure ...
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How does a double spend get resolved when two miners find conflicting blocks at the same time?
I was trying to learn about Bitcoin and its flow. Actually, I was stuck how the control flows in solving the double spend.
For eg. if Ta and Tb are a double spend of the same transaction with ...
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How does SPV prevent double spending of UTXO?
I am new to Bitcoins. I have read about how double spending is prevented in Bitcoins.
Suppose A, a peer, receives 'B' BTCs from various transactions: B1,B2,B3, etc. Also, A had spent 'S' BTCs in ...
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Is it possible to use Selfish Mining to steal bitcoins?
Is it possible to use the Selfish Mining algorithm to steal bitcoins?
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How confirm my own doublespend transaction got confirmed
Transactions in the testnet are right now almost always double spent with a new txid (possible due to tx malleability). This is actually quite nice for testing purposes.
So I'm wondering - when I ...
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Double spending race attack first transaction
In tackling double spending, does the protocol enforces that only the first transaction (and by first i mean the first transaction to be send to the network) is considered as valid ?
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Does any pool accept higher-fee transactions of a double spend, instead of the earlier one?
Some pools use a modified bitcoind that uses different rules for choosing the transactions to include in a block. Are there any pools that knowing one transaction to be included in a block would ...
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How to minimize risk when accepting zero confirmation payments?
I'm trying to setup a way of accepting Bitcoin payments in real life situations, where waiting for confirmations is typically not an option. I understand this is never 100% risk free (especially with ...
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Why is Poisson instead of Negative Binomial used for computing attacker's potential progress?
In chapter 11 of the Satoshi's paper it is claimed that:
The recipient waits until the transaction has been added to a block
and z blocks have been linked after it. He doesn't know the exact
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Is performing a 51% attack / double spend on Bitcoin illegal?
Suppose I had an ultra large ASIC from the future, and could perform a double spend on the core Bitcoin network. At this point in Bitcoin's development, it is no longer a game - there's real money ...
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Double spend transactions flag the node as "bad"?
I'm playing with raw transactions. It's easy to send two signed valid transactions at the same time from the same output to different addresses (making a double-spend attack). My doubt is: if I make ...
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How to perform a double spend attack in websites that accept transactions with 0 confirmations?
To perform a Finney attack or a 51% attack I need to have lots of computational power, but in this case (a website that accepts transactions with 0 confirmations) it seems to me that I only need to ...
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What to do about a "stuck" transaction?
I started the standard client with --rescan instead of -rescan after switching wallets and before synchronizing with the latest blockchain, and made an going transaction.
This transaction got "stuck",...
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Is something gained by double spending myself on a 51% attack?
I try to understand what consequences double spending may have.
Let's assume I own 51% of the network and own three bitcoins wallets. If I double spend the coins from Wallet A to B and C - would I ...
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Broadcast a signed transaction
I sent money from 4 inputs to 2 outputs, one of which I don't control. The transaction's fee is too small (didn't change my settings and the transaction fees got a lot higher, recently) and will not ...
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Single tx included in two different blocks
https://www.blockchain.com/btc/tx/a7bacce00e5df85d3547a3f83ac10c65eec30f715c1d77d8d4a7bc17fd470965
How is it possible that a single tx is included in two different blocks?
Isn't it considered double ...
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reproduce CVE-2018-17144 (inflation bug) on regtest for learning
I'm reviewing CVE-2018-17144 inflation vulnerability for learning. I think I reproduced the error on regtest. Is it a correct way to reproduce it? I want to know if I'm missing something about it.
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Why we need mining?
I know is related to these:
What is the rationale behind Bitcoin mining?
Why do we need Proof of Work in bitcoin?
But I don't fully understand those answers, and I think usually is much easier to ...
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Which clients offer a way to replace unconfirmed transactions?
On this site, we see a lot of questions from people who have sent a transaction which isn't being confirmed, often because they have neglected to include an adequate fee. The Satoshi client doesn't ...
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If two parties submit a conflicting transaction between each other, how does the network decide which one is correct?
Let's say parties A and B both submit a transaction to the blockchain with a different version of what happened. Party A submits a transaction saying Party B gave him 3 BTC and Party B submits a ...
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What's the easiest way to someone to double-spend 0-confirmation transactions?
I heard there is a desktop app today that 'easily double spends 0-conf tx'. Which is it? Is anyone working on a mobile version of this app?
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Would first-seen prevent a double spend attack?
It takes approx. 8 seconds for a transaction to propagate through the entire Bitcoin network. If we got rid of the concept of replace-by-fee and replaced it (no pun intended) with a first-seen ...
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Is it possible to execute a double-spending attack in Ripple during a network split?
From the spec (emphasis added):
Under a net split, a ledger may be closed by the minority of network, this ledger may be discarded in the future.
Does this mean it would be possible to spend twice,...
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Race Attack vs. Double-Spending Attack: are they same?
Race Attack vs. Double-Spending Attack: are they same?
I know definition of both attack both some times it is called as "race attack" and most of the time called as "double-spending". I guess (maybe) ...
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Why can't a transaction be redirected after it is signed? [duplicate]
Scenario:
Step 1: User-1 initiates the TXN-1 to pay to User-2 and the TXN is not yet confirmed with the ongoing block POW.
Step 2: What prevents fraudster (anyone a miner or someone listening/...
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How does the blockchain prevent spending money during a "short fork"?
I'm currently reading "Mastering Bitcoin" (i haven't finished it tho, but i don't see my answer and it bother me so I prefer asking it here) and there's something i don't understand. So from what I ...
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how does bitcoin solve the same chain replay attack?
Let's say I send 10BTC to Bob. I have 30 BTC. So after transferring, I should have 20.
Now, after I transfered 10, transaction can be copied and broadcasted to the network again by Bob(he might have ...
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