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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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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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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How does bitcoin double-spend influence on omni asssets?

I have a question about omni layer and bitcoin double-spend. I'd be very grateful if someone answered on it. Assume that I performed a transaction tx_1 in bitcoin network from address X to adress Y ...
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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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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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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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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
52 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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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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54 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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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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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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What does a double spend (CVE-2018-17144) look like if I gettransaction it?

Just wondering what the output from gettransaction (or should I be using getblock?) would look like if I passed it a txid(or blockhash) that contained a set of transactions that exploited the double ...
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Is a 51% attack on bitcoin likely?

Given that the majority of bitcoin processing is done in China (source: https://bitcoinmagazine.com/articles/report-links-74-bitcoin-mining-china-sees-threat-network/), is it possible for a single ...
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Regarding CVE-2018-17144 and test cases

Regarding the serious bug found (CVE-2018-17144) I am note sure if I understand the full scope of it correctly. As far as I understand, any block containing a double-spend of a transaction output ...
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3answers
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Are bitcoins (or fractions of bitcoins) labeled with IDs?

Many sources describe the double spending problem by saying something like "people cannot be able to spend the same bitcoin twice." [1][2][3] So are bitcoins, or the smallest allowable bitcoin ...
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double spending problem

Why is double spending a problem. Suppose I have 1 bitcoin and I intend to send 1 btc to Alice and 1 btc to Bob. Once I send 1 btc to Alice, UTXO of 1btc will be unlocked,transferred to Alice.No ...
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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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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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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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27 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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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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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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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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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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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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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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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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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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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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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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112 views

Does double spending happen at all?

I'm a complete beginner to anything and everything about cyrpto. 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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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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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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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
72 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
91 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
147 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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706 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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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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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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474 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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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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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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67 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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108 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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468 views

Bitcoin Transaction Stuck, Attempt to double spend with higher fees

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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622 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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401 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 ...