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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2 votes
2 answers
108 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 ...
1 vote
1 answer
39 views

Modelling random walks for double spending based on hashrate

I'm reading Analysis of hashrate-based double-spending where the following assumptions are made (on page 5): The total hashrate of the honest network and the attacker is constant, say H. Let the ...
-1 votes
3 answers
76 views

How 2 chains co-exist together?

I am not able to understand, how 2 chains co-exist together, like these were the observations which are ambiguity for me: In one reading I have read, Only longest chain is valid and and rest chains ...
0 votes
3 answers
160 views

Can miners double-spend with two transactions in one block?

Let's say Alice sends 5 BTC to Bob and Alice tries to make double spending by again sending those same 5 BTC inputs to carl and lets say that Alice is also a one of the miner node. Here Alice tries ...
0 votes
3 answers
73 views

How does Bitcoin prevent double-spending without penalizing miners?

In the network nodes below as shown in picture: Let's say A is trying to double spend by sending bitcoins to B,C (A->B) and (A->C) and let's say A tried to relay (A->B) transaction to honest ...
0 votes
1 answer
67 views

Why does the network allow a fraudster (double spender) to broadcast a transaction to a single node (the victim)?

Let's assume for the sake of argument that a fraudster is able to create blocks faster than the rest of the network. Given that, they would be able to achieve double spending by making a fraudulent ...
2 votes
1 answer
75 views

Double Spend for small value transactions

maybe a naive q, but I read in a book that for small value items you don't really need to wait for confirmation of a BTC transaction (i.e. dont need to wait for it to be added to a block): I ...
2 votes
1 answer
121 views

What is an inflationary bug in the context of bitcoin?

I often hear that the worst bug that could impact bitcoin is an inflationary bug. But what exactly is meant by 'inflationary bug'?
1 vote
2 answers
100 views

Why does the longest chain rule make the most sense to deter double spending?

If there is double spending occuring, I don't understand why the longest chain rule would decrease the likelihood for only one transaction to be confirmed. Can someone explain step by step why this ...
0 votes
1 answer
85 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 ...
2 votes
2 answers
385 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" ...
0 votes
1 answer
46 views

What stage of the bitcoin protocol deals (or 'solves') the double-spend problem?

I understand that a key innovation in bitcoin is that it solves a key problem faced by previous attempts at a digital currency: the double-spend problem. In addition, I also understand that the ...
3 votes
3 answers
287 views

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 ...
0 votes
1 answer
45 views

Can Finney attacks only be made by miners?

I read this article about double spending attacks. The article has a sentence that goes like this: "Finney attacks can only be executed by miners, and are therefore fairly technical and obscure.&...
0 votes
1 answer
63 views

what kind of a double spend attack is a career attack?

there is an article that name different type of double spent attach like "Several variations of attacks could allow miners with bad intentions to double spend. Included are the Finney attack, ...
1 vote
2 answers
204 views

What is the downside of having a default setting in which nodes will invalidate blocks that comprise a surprise reorg?

Suppose that suddenly, out of nowhere, a longest-chain appears that reorgs the last 15 blocks. Such an attack could be accomplished from time-to-time even by a minority attacker who is either lucky ...
3 votes
2 answers
83 views

What verb best describes "causing another block to become stale"?

For example, suppose I'm selfish mining; you publish a block and then I immediately publish two, what did I do to your block? Similarly, if I'm executing a double-spend attack, my goal is to ?___? the ...
0 votes
2 answers
119 views

Why is PoW even necessary?

So I understand the concept behind PoW (that if someone wants to overturn the current chain, they'd have to do all that work again). But why is it even necessary since transactions are confirmed only ...
1 vote
3 answers
60 views

What happens if a transaction is duplicated across different blocks?

I'm sure I am missing something trivial here but I have a question. Let's say there are Node A and Node B. We send a transaction to both nodes. Both nodes now contain an unconfirmed transaction in ...
0 votes
2 answers
43 views

Why won't the second transaction pass the confirmation process

I'm reading How does a block chain prevent double-spending of Bitcoins? , and it says The first transaction would be approved via the confirmation mechanism and then verified into the subsequent ...
0 votes
2 answers
90 views

How can double-spending occur?

I'm new to Bitcoin and trying to understand how the double-spending problem can occur and implicitly, the need for "mining". Let's say Bitcoin worked the following way: In the network, one ...
0 votes
0 answers
40 views

Why the Proof of Work solve the double spending problem?

I'm learning about blockchain and I somehow struggled to understand why the POF is the solution of double spending in bitcoin. From my understanding, the POF is the method to create new block, which ...
0 votes
1 answer
75 views

Where is there a graph of total miner revenue (BTC) per unit time (e.g. day)?

Basically I'm looking for this graph, but denominated in BTC https://www.blockchain.com/charts/miners-revenue or this graph plus the block reward https://www.blockchain.com/charts/transaction-fees I'...
1 vote
1 answer
62 views

Noob question: Why is there not a limit of the number of blocks in a chain revision?

I have a noob idea and I want to understand where I'm going wrong :) Say nodes agreed on a block revision limit, say, 6. This would mean that if they see an incoming chain that is longer than the ...
0 votes
2 answers
53 views

If there was an easy way to check for double spends, will consensus algorithms be needed?

Currently, checking for double spends is very computationally expensive, so consensus algorithms, like POW, were put in place to more easily prevent double spends among other things. Ignoring the fact ...
1 vote
1 answer
96 views

What happens if a miner deliberately ignores a transaction, and "wins"?

Suppose a miner decides to solve the nonce for a particular block, where the miner deliberately excluded a particular transaction from this block. The miner "wins", i.e. they found the nonce ...
0 votes
1 answer
61 views

Why can the race between the honest chain and an attacker chain be characterized as a Binomial Random Walk?

I am not familiar with Bitcoin, hope someone can tell me why. Thank you! Let's consider the following scenario. The probability of the attacker finds the next block is q and the probability of the ...
0 votes
0 answers
53 views

How to create a double spend to prioritize a new transaction over a previous unconfirmed transaction?

I'd like to generate a double spend transaction and increase the gas fees over the previous, unconfirmed transaction that has been stuck for a week. I know there's other answers regarding double spend ...
1 vote
1 answer
177 views

Why don't bitcoin nodes invalidate new blockchains that don't contain all the data of the old blockchain?

If nodes only accepted new valid blockchains that contained all the data of the old blockchain, then miners will still be able to add blocks to the current blockchain because their blockchain will ...
0 votes
1 answer
88 views

Duplicate Transaction Prevention

I'm trying to understand Bitcoin a bit more and I'm struggling to find an answer for this scenario. Say for example I have access to a wallet and I have give a person on the other side of the world ...
1 vote
2 answers
112 views

Mitigating a Double Spend Attack by Punishing the Attacker?

One of the main reasons it's not safe to accept Bitcoin with 0 confirmations is due to the possibility of a double spend (where Mr. Scammer first sends 1 BTC to Alice and then creates an identical ...
0 votes
1 answer
50 views

terminology and conceptual question about progress of PoW

what is wrong about thinking prbobability of attacker increases with time t that goes into PoW since they have more time to secretly mine their alternate blockchain ? This refer to double ...
6 votes
2 answers
343 views

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 ...
1 vote
1 answer
53 views

What were some discussed and current potential issues with pre-forked Bitcoin coins from August 2017 that have never moved since then?

I was speaking to a friend that mentioned that there were issues with pre-forked Bitcoin coins from Aug 2017 that never moved. He wouldn't tell me exactly what the potential issue was, but what were ...
2 votes
1 answer
183 views

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 ...
1 vote
1 answer
60 views

Does difficulty adjustment apply when you mine in secret?

Imagine you have an enormous amount of hashpower (say a nation state level attack) and you mine in secret. Does the difficulty adjustment apply specifically to your secret chain? Because that would ...
0 votes
1 answer
98 views

Do you have to keep broadcasting transactions until mined?

From what I know, you can broadcast a transaction including input addresses, output addresses, and amounts, which is signed by your private key. I often hear that your transaction might not be mined ...
1 vote
1 answer
176 views

Safely Accept Bitcoin Payments with 0 Confirmations [duplicate]

GAP600 is a service (that has processed $5 billion in cryptocurrency) which allows exchanges and payment service providers to process Bitcoin payments instantly (0 confirmation trx). It guarantees a ...
0 votes
1 answer
39 views

Is PoW and consensus unnecessary without double spending?

Satoshi's whitepaper claims that the reason there must be a consensus on all transactions is to solve the problem of double spend. I'm curious then, how would a non-consensus based system work if ...
1 vote
2 answers
64 views

Notable examples of double-spends

Do you know any real-world examples of double-spends, where the second transaction was accepted to the block? There's https://doublespend.cash/ for BCH but for BTC I would like some examples where the ...
3 votes
2 answers
51 views

Which transaction would get confirmed in an uncongested network?

Scenario: Mallory sends some bitcoin with a $1 fee Later, Mallory double spends her transaction with a $5 fee A new block is found In an uncongested network with an average transaction fee of ~20 ...
0 votes
1 answer
129 views

why is transaction history from genesis to date necessary to store on the blockchain to prevent double spending?

I am beginning to understand the mechanism of bitcoin blockchain, and I was wondering something. The transactions history represents the 'state' of the bitcoin at any point (or EVM according to the ...
2 votes
2 answers
3k views

Negative Bitcoin Balance

I was playing around with bitcoin and I discovered an address that appears to have a negative balance on the blockchain. The details of this address are below. At the time of writing the blockchain ...
1 vote
1 answer
69 views

How the bitcoin network solves the double-spending problem by adding all the transactions that happened at the same time into one block

According to my research, I understand if person A sends 2 BTC to person B and at the same time person A sends the same input to himself before the input is considered as spent. So, now there will be ...
3 votes
3 answers
325 views

NBitcoin - how to set RBF to true in order to give higher fee for transaction

I have a few transactions staying unconfirmed - been a few days now. I suspect the minimum mining fee was upped - 15 minutes prior I was still doing hundreds of transactions a day at that fee - but ...
1 vote
1 answer
89 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 ...
1 vote
1 answer
374 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 ...
1 vote
1 answer
75 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 ...
1 vote
3 answers
203 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 ...
0 votes
2 answers
210 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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