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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28 views

double spend the mempool to outbid an attacker

if I spend some input in a tx and a few seconds later spends the same input with other inputs in another tx with higher fees. If the first tx is still in the mempool would the 2nd tx replace the first ...
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1answer
39 views

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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1answer
35 views

Exchange Confirmation Requirements

What does the minimum confirmations required for a deposit mean for the security of exchanges? For example, Coinbase requires 3 confirmations for Bitcoin deposits. Suppose an adversary deposits 10 ...
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1answer
16 views

How does longest chain propagation take place in bitcoin?

Let's say the valid blockchain that Node A has is: B1->B2->B3 Now, I am gonna cheat since I have lots of computing power. What I do is I download the above blockchain that Node A has and start ...
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3answers
178 views

Does double spending happen at all?

I'm a complete beginner to anything and everything about crypto. I've been trying to research a lot about it, and I have recently just been trying to learn and understand some of the basics. I was ...
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2answers
296 views

Double spending on testnet or regtest?

I'm currently doing a research on bitcoin and I would like to know if there is anyway to replicate double spending in the testnet or regtest? If isn't possible is there any other type of "attacks" ...
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2answers
198 views

How would one relay a raw tx double spend to a node that accepts it?

All of the pushtx sites reject the tx as a double spend. Would I have to run my own node through bitcoind? How would one do this?
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1answer
39 views

How to find if two transactions in mempool are conflicting?

There are lots of transactions over the mempool of the bitoin. However, there might be double spends. How can we verify whether two transactions are conflicting, i.e. they are double spends of a ...
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4answers
38k views

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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1answer
33 views

Could it be possible to secure transactions against double-spending with other utxos?

I'm new to Bitcoin Script, and I was wondering if it is possible to use funds from one utxo to "insure" that other utxo will not be double-spent (until the Lightning Network will save us all). Suppose ...
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2answers
3k views

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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4answers
161 views

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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1answer
572 views

Bitcoin Transaction Stuck, Attempt to double spend with higher fees [duplicate]

I made a BTC transaction a few days ago, where I set the fee amount way too low. It seemed that the transaction was lost in limbo. I did some research, and apparently you are able to double spend ...
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2answers
72 views

Cryptocurrency acceptance

I heard that the recommended waiting confirmation time for a bitcoin transaction is 6 blocks/ 1 hour. So a shop which lets its customer to pay in bitcoin without any waiting for confirmation would ...
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0answers
60 views

Wallet's role in a double spend attack

How does my wallet allow me to double spend? As soon as I make a payment, shouldn't my wallet delete those bitcoins or does it leave them until the transaction is added into the blockchain?
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1answer
45 views

Handling “dead” (double-spent) transactions in my mempool

Say I receive transaction A and it is in my node's mempool and unconfirmed. Then a block gets mined directly, which spends one of transaction A's inputs, rendering transaction A invalid. What can I ...
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0answers
27 views

Double spending problem 2.0 [duplicate]

How is the following case handled in bitcoin blockchain? Initially Alice has only 2 bitcoins. Suppose Alice sends 2 bitcoins to herself(tr1 i.e. Alice to Alice) and then 2 bitcoins to Bob(tr2 i.e. ...
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2answers
64 views

Double spending problem in Bitcoin

Suppose Alice sent 2 bitcoins to Bob, Bob ships the product to Alice, then Alice sends 2 bitcoins to herself. Why is this a problem ? If both the transactions are approved then also Bob gets his 2 ...
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1answer
39 views

If I were executing a 51% attack, would I be broadcasting my state of the network to nodes?

In the scenario where an entity has control of greater than 51% of the hash power and wishes to build a longer chain where they double-spend previously confirmed transactions, do they broadcast the ...
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1answer
51 views

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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1answer
45 views

Understand double spending through an example

Let’s suppose you have 1 BTC which you try to spend twice. You made the 1 BTC transaction to a merchant (Transaction T1). Now, you again sign and send the same 1 BTC on another Bitcoin address to try ...
2
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1answer
58 views

What happens if I spend a double spend?

Given I can receive a double spend and potentially re-spend it after 1 confirmation, what happens to that transaction once the double spend is detected during a blockchain reorg?
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1answer
189 views

Which wallets support double spending?

Which wallets support double spending? i.e. cancelling a transaction with 0 confirmations by using higher fees
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1answer
25 views

Double Spend Behavior on First Network Propagation

Supposing there is a double spend, call the transactions T1 and T2. If someone propagated both transactions within a short space of time to the network, of course only one of them can make it into the ...
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2answers
239 views

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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1answer
75 views

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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1answer
500 views

Does proof-of-work contribute directly to prevent double-spending?

I know similar questions have been asked before (e.g. How proof of work prevents double spend) but I'm struggling to visualise the solution to double-spending being directly reliant on proof of work. ...
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1answer
65 views

How to prevent double spending Bitcoins?

If I create a transaction, my node will check my UTXO's and if i have enough BTC to do this transaction it will be mined. So let's say I want to spend 12 BTC to Anna. The System will check if i ...
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1answer
4k views

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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0answers
38 views

Bitcoin, BTC.com and monitoring double-spend attempts

I'm reading Analysis of hashrate-based double-spending article. On page 10 there's a table listing probability of successful double-spend attack in relation to required number of confirmation. ...
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2answers
15k views

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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2answers
212 views

Can a malicious Internet Service provider launch a double spend attack?

If a malicious internet service provider completely controls a user's connection, can it launch a double-spend attack against the user? How much computational effort would this take?
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1answer
42 views

Who first defined/coined The Double-Spending Problem?

The Double-Spending problem is a variant of the Byzantine Generals Problem which has a nice write up by Lamport, Shostak and Pease. But who first coined/defined the specific Double-Spending problem? ...
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3answers
96 views

What happen when 2 transactions with one doublespending the other reachs the same block?

Let’s have 2 transactions. The second one is duplicating Input of the first one. Both have very high fees so they are selected by miner to be included in the same block but before passing validation (...
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1answer
249 views

Proof of Stake - double spending

I'm unsure how Proof of Stake prevents double spending. In PoW it's evident that I need 51% of the hashing power of the network, to "overtake" the real chain with my fraudulent fork. But what stops ...
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1answer
3k views

Can someone explain this double spend on blockchain.info?

I'm confused by double-spend linked below, in which both transactions ended up in blocks mined by different miners. Specifically, I'm wondering if there's any way to tell what exactly happened based ...
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2answers
2k views

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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2answers
650 views

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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1answer
30 views

how is the current hashing power (of the entire network) measured (in real time)?

1) does hash power refers to mining nodes only ? 2) we don't know how many nodes there are on the bitcoin network , correct ? how do we count them ? 3) would we need to know [2] in order to figure ...
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2answers
191 views

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 ...
2
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1answer
990 views

My blockchain.info wallet was hacked. How can I create a double send to foil the attacker?

This is the transaction. https://blockchain.info/address/1F8EP97jgQx8QD6XMRg2bCHHrJrZEMUTRt Which is still unconfirmed. I am trying to use https://coinb.in to create a double spend transaction with ...
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1answer
472 views

Ripple's validation of transactions / Ripple white paper?

Is there a ripple white paper or some safe source to understand how the transactions are validated and made in the ripple network? VS Bitcoin, XRP is not mined, so how is the agreement reached? (I ...
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1answer
76 views

Why isn't the block hash used to calculate accumulated work?

Why is this idea flawed? It doesn't seem to be a bad idea at first, because the miners should be incentivized to extend existing chain, instead of to "remine existing blocks", since such "remining" ...
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2answers
2k views

What is the Ripple equivalent of the “51% attack?”

In Bitcoin, if a participant gains control of more than 50% of the hash power, they can execute a double-spending attack. The "attack" could come from within, say if the existing powerful miners ...
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2answers
111 views

Can two or more transactions sent from the same address be mined in the same block in Bitcoin's blockchain?

Imagine a person Bob has 10 bitcoins in his wallet. He wants to send 5 bitcoins to Alice and another 5 bitcoins to Uncle Tom simultaneously (in separate transactions). Will both Bob's transactions be ...
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1answer
67 views

double spend attack: Is this actually true for the more time progress the higher the probability of success for attacker

I'm new here. I have a question here. Some experts keep saying that this assumption isn't formally correct and I don't really understand why or why they might be wrong. In the double spend attack; ...
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2answers
44 views

can attacker and honest node in double spend ever tie?

in bitcoin white paper there are only attacker and honest nodes. you have p, and q for probabilities. in double spend attack, in bitcoin whitepaper, can we talk about possible tie of attacker and ...
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1answer
38 views

Why “double spent” can only happen if attacker controls 51% (or more) of the network compute power?

As per many descriptions block hash is calculated based on it's headers and nonce field. The latter gives a chance to get the value that is less then a target by incrementing it. If it's a lottery why ...
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0answers
142 views

Sybil attack with IOTA? [closed]

IOTA is one of the DLTs uses DAG (Directed Acyclic Graph) as data structure. The solutions to attacks proposed by IOTA white paper seems unconvincing, in particular, in case of double-spending, it ...
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1answer
52 views

in the white paper you have 2 sides : attacker and honest node

What does it mean that there is either the attacker or honest node. This means that within 10 minutes either attacker or honest node mines a block but what about neither OR another side ? How could ...

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