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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106 views

In Litecoin every single block is mined every 2.5 minutes, double spending?

In Bitcoin it takes roughly 10 minutes for every block to be mined. In Litecoin it takes 2,5 minutes. 2.5 minutes in Litecoin mean that transactions can be confirmed faster. In Bitcoin these 10 ...
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2answers
45 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
42 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 ...
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54 views

double spending , you can create money out of thinner air [duplicate]

I am a little confused about how doublespending is done. The basic case is basically creating transactions to the seller and yourself and simultaneously broadcasting those. This is the very classic ...
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1answer
55 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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1answer
44 views

what does it mean to have >51% hashing power for mining a block? [duplicate]

Can someone please shine some light on this and how it links to the analogy between honest node and attacker ? also can attacker start mining 2 blocks ahead ? or 3 or 4 blocks ahead ? In the white ...
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1answer
45 views

Security via Proof - of - Work

I am reading Satoshi's original paper, merely for the sake of understanding the concept. I have minimal computer science background (some), mostly just mathematics. In Section 4. Proof of Work of ...
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2answers
187 views

What happens if full nodes don't check for double spends or deliberately lets a double spend TX pass and then this full node relays the transaction?

I am studying about Bitcoin and Blockchain tech via the Princeton crypto course, and it mentions that Full nodes do the following checks : i)transaction is valid with the current blockchain, ii)...
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1answer
104 views

What happens to rejected transactions ( i.e double spend or invalid transactions)?

Do they get put in an orphaned block or not get put into any block at all?
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2answers
210 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 ...
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2answers
228 views

Possible error in the white paper Calculations section?

Section 11 presents calculations of the probability of double spending, P(z, q), given an attacker relative hash rate q and a block count z. P(z, q) can only be understood by knowing exactly what z ...
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4answers
198 views

What can make an unconfirmed transaction (0-conf) an invalid one other than Double-spend?

It's obvious that inputs that already been spent will make the transaction invalid (pure double-spend scenario), but is there's anything else that could make a tx invalid? Invalid inputs? Invalid ...
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1answer
49 views

Can there be double spend between propagation of block chains between 2 set of peers?

It shouldn't be as simple to do a double spend. I think I am missing something here. I understand Consensus rules and P2P networking. But since a node is connected only to some limited number of other ...
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2answers
117 views

How two transactions with the same hash can cause double-spending

Let's consider following situation: Vendor owns address X. Adversary sends transaction T1 to X with hash Y and receives product from vendor. Adversary sends transaction T2 to address which he owns ...
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3answers
190 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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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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2answers
241 views

Why are blocks in a permissioned blockchain linked together?

My question: Do the blocks in a blockchain without proof-of-work (i.e. a permissioned blockchain) have to be linked together via a cryptographic hash? Longer version of my question: (Please correct ...
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0answers
27 views

Can low-cost purchases be accepted safely with no confirmations? [duplicate]

From reading online, the general sentiment to this seems to be "no". You need at least 1 confirmation to prevent a double spend attack. But in Mastering Bitcoin, there's this note: A common ...
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1answer
148 views

Is “fee higher than block reward” attack possible?

Imagine the following scenario: I send you 1000 BTC. After 6 confirmations, you give me what I bought. I create another transaction with 900 BTC to my own wallet and 100 BTC as transaction fee, using ...
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1answer
135 views

Transactions in a shorter blockchain branch

As I understand it, in a situation where two miners solve a block at the same time, a branch is created on the blockchain which is resolved when one branch is built upon, and thus becomes longer than ...
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1answer
212 views

Double spending UTXOs

I know that the inputs for a transaction(which is not coinbase) are UTXOs. Are UTXOs kept track of by some servers and also the owner's wallet? If there are servers which keep track of UTXOs, is it ...
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1answer
880 views

How does the bitcoin exactly prevent Double spending attacks?

I recently started reading about Bitcoin, the idea seems hard to get, and I'm trying to understand the basics now. I read the white paper by Satoshi Nakamoto but I still have some confusions First, ...
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1answer
43 views

In case of a double spend (after double spend and prior getting resolved) what is actual account balance?

For eg. if Ta and Tb are a double spend of the same transaction with different outputs. These two transactions can flow through different path in the network, and assume flow in exactly opposite path. ...
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1answer
100 views

Mining & The Double Spending Dilemma

My understanding of the double spending problem is as follows: Suppose account A has 1 Bitcoin and sends it to account B and then creates another transaction which sends the same Bitcoin to account ...
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490 views

why is the double spending problem is a problem in cryptocurrency?

The bitcoin original has the "double spending problem." But in a transaction using standard currency (dollar), the double spending problem is not a problem. Why is this a problem in crypocurrency?
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how to double spend Bitcoin transaction?

How it's possible to double spend a transaction if the transaction outputs are already spent? and why these types of attacks are not preventable? is it about blockchain sync time between nodes?
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288 views

Not sure if I accidentally double spent my LTC LITECOIN

LEDGER NANO S - CHROME APP LTC LITECOIN I just sent two transactions (with different amounts) from one address to the same receiver one after another. While sending the second the first was still ...
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3k views

How do I double spend using electrum?

I have created a transaction several days ago, with a very low fee. The transaction was meant to remove dust from my wallet, so increasing the fee won't help as the transaction is very big (1.6KB), ...
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1answer
71 views

What are the mechanics of verifying that an output transaction is not spent?

I am trying to understand the mechanics of how a bitcoin transaction works. When the output gets consumed by a later transaction, who and how prevents this output from being consumed a second time? Do ...
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2answers
120 views

Can I save stuck bitcoins by creating a completely new transaction? [duplicate]

I tried to make a bitcoin payment but accidently set a too low transaction fee so it got stuck. By now the payment is cancelled so I don't want to do this transaction anymore. Can I now instruct my ...
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1answer
658 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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1answer
1k views

From multibit to electrum : low fee and unconfirmed parent

I made 3 btc transfer from my old Multibit classic wallet a few weeks ago (dec. 11), then I discovered that the fee was far too low for the transfers to be confirmed. I then restored my original ...
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1answer
495 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
255 views

Why is CPFP (Child pay for parent) immune to double spend?

Assuming I have 10 Bitcoins in my wallet and I send 4 BTC with a tiny fee and it gets stuck in the mempool due to a low transaction fee. If I understand CPFP correctly I would then send a second ...
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1answer
98 views

Can I double spend this transaction?

b9d6d458f312b6ce2ef27bbb4a4a88f95e4a5db7aa04c9ab1f6225ecde47a77e Can I move it ? Thanks for your help
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1answer
64 views

Complete Tech Spec

Where can I find a comprehensive description of exactly how Bitcoin works. I'm not interested in an analogy, I want to know everything, including the maths.
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2answers
106 views

Does the entire blockchain have to be recomputed to validate a transaction?

Are transactions validated by recomputing the entire blockchain? If not, how else can it be confirmed that a bitcoin I'm attempting to transact is one that I actually had come into acquisition of ...
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1answer
1k 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
787 views

Unconfirmed transaction / double spend warning [duplicate]

I transferred some coins from my Electrum Wallet to my Coinbase Wallet, however the transaction got stuck as unconfirmed (possibly because of low fees). It has been already 19 days since the ...
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1answer
206 views

Is this considered double spend?

I had a Receive transaction worth 0.185btc I was confident that it was ok since I saw 5 confirmation before I close the wallet. The next day when I checked I saw a sent transaction with 0.185 btc ...
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1answer
268 views

After being officially canceled, SegWit2x is live. Will transaction replaying be massive ? If yes what does this means?

As you know, segwit2x was officially canceled last week, but some miners decided to still go forward today, and some exchanges like coinbase plan to support the hard fork. So things will happen like ...
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1answer
129 views

double spend problem and trust

I am very new to bitcoin and sorry if the following is too simple. As far as I understood, if there is a double spend problem, the longest chain - collecting most work - will take over. However, ...
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2answers
126 views

How does the network know the legitimate chain in a double-spend attempt?

Apologies if this has been covered, but there's one area of the Bitcoin network that is not clear in my head, and it's intimately linked to the double-spend problem. Suppose Person A is purchasing an ...
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1answer
40 views

Can one node receive two transactions from the same user (doublespend)?

I'm learning how the blockchain works. I've read that when someone (say Alice) send twice a transaction to two different peoples (Bob and Charlie) such that Alice has only enough to pay Bob or Charlie,...
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2answers
57 views

Is in-person double-spending attacks negligible on bitcoin payments?

If I'm planning to accept in-person payments in a store, is it negligible a double-spending attack or isn't it too hard to do?
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0answers
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Bitcoin Paper: Why do we need the probability of catching up in double spend attack?

In the Bitcoin original paper, we have two probabilities: 1- Probability of generating k number of blocks in the period T in which z confirmations are generated. 2- Probability that the attacker ...
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2answers
82 views

What is the average time for an honest network to find a block when its hash rate is p?

let p be the hash rate that belongs to honest network and T be the time a block is found. In the Bitcoin paper it's said "assuming the honest blocks took the average expected time per block...". In ...
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1answer
164 views

do isolated blocks create forks in block chain? (with forks I mean branches that are no longer valid) If yes then how does the node redeem itself? [duplicate]

I'm a newbie to cryto and wanted understand this. what happens to the chain when the isolated block is formed (in case of a double spend) ? Since chains only add blocks that come from the longest ...
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1answer
2k views

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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2answers
622 views

100% double spending attack probability

When we plot the attacker's computational power against the probability of double spending with a number of blocks equal to zero, we always get a chance of 100%. This plot is based on the original ...