Relates to attempts to harm the Bitcoin network. In cryptography, an attack is a method/technique to break the code. Bitcoin also has to deal with other types of attack, such as double spends and denial of service.

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How many bitcoins would it require for a sustained DOS attack on bitcoin network?

How many bitcoins would it require for a sustained DOS attack on bitcoin network? Without transaction fee, how many bitcoins would that be? How many transactions could we generate with 1 BTC ...
15
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219 views

Have any SPV users lost money because they accepted forged bitcoins?

I'm making a list of real-life examples of occasions where bitcoins were lost to various known attacks. One of these known attacks is that lightweight (SPV) wallets can't verify whether a transaction ...
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1answer
73 views

Implicit/Tacit mechanisms in Bitcoin Core disclosing Selfish Mining

I'm referring to the selfish mine attack described by two researchers from Cornell University who describe a "possible" attack with lower than 51% hashing power. Now it's interesting to know what ...
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80 views

Which release fixed CVE-2010-5141 (attacker can spend any coin)

This post by Mike Hearn relates an interesting bit of history: When Bitcoin was first released, it contained two completely fatal bugs that made the entire system worthless. Fortunately, they were ...
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148 views

Simultaneously Solo and Pool Mining

It's possible to send shares both to a localhost GBT "pool" (e.g., Bitcoin Core's) and to a remote Stratum pool.* Now, if I discover a block, won't both my localhost GBT "pool" and the remote pool ...
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1answer
86 views

How does bitcoin prevent this network splitting attack?

How are malicious nodes prevented from, after getting the nonce of a new block found by someone else, broadcast it to the other nodes claiming it to be its? Also, how does the bitcoin system solve ...
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1answer
96 views

How can one simulate and analyze attacks on the Bitcoin network?

Are there any other platforms or tools beside TestNet where I can simulate and analyze various attacks like double spending (finney/block withholding attacks etc.)?
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2answers
846 views

Why does an adversary have to control 50% of the computing power to double spend?

If transactions in a block are valid, in order to add that block in the block chain, a proof of work needs to be found. I have read the bitcoin paper by Satoshi. If the difficulty of the proof of ...
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1answer
73 views

Pseudo-Node and putative attack vectors on the network

Pseudo-Node is discussed here on Reddit's /r/Bitcoin Essentially it functions to relay calls from connected nodes in a random fashion. This was an experiment into how easily can full nodes be ...
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45 views

Is it possible to run a simple attack on a previous version of the client in testnet mode?

I need to simulate an attack locally or in testnet (if possible) for academic purpose, on an old and bugged version of the bitcoin core client. I am in posses of test BTC in the last version. I want ...
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1answer
156 views

What if some group of people start sending small transactions from wallet to wallet just to make the blockchain bigger?

What if some government start using their computers to move the tiniest amount of Bitcoin possible, from wallet to wallet, just to make the blockchain REALLY big? Is this possible? And also, is it ...
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2answers
176 views

How safe is bitcoin with regard to a random address generation attack? [duplicate]

Imagine an attacker implementing something like the following pseudocode on the fastest ASIC farm money can buy: attack(blockchain, my_address) addresses = ...
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1answer
547 views

When to worry about 1-confirmation payments

A customer sends me a payment for some digital good at my service, where delayed delivery is a deal-breaker, so I only wait for 1 confirmation by the network before releasing the links for the ...
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1answer
134 views

Specifics on “Race Double Spending Attacks”?

Hi guys I am doing some research on double spending in the bitcoin network several ideas have been confusing me: In prevention of Race attacks, merchants are advised to "connect to a large random ...
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2answers
197 views

What happens if I fork an older block chain and rejoin the network later?

Let's call it a "time machine attack". Suppose I have an isolated network of n clients with a significant hash rate, install my client software on that and start mining on an older blockchain. Since ...
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4answers
224 views

Wouldn't the “malleable transaction” attack be foiled by common sense?

I'm trying to understand the malleable transaction attack, as it seems to me that only a rather careless operator would be vulnerable in the first place, as described below. Mainly to clarify my ...
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1answer
95 views

Isn't bribe smearing possible because no payee signature is required?

The Bitcoin protocol does not require the payee to sign for a payment; only the payer signs (the payer signs a hash of the payee and payer's public keys). In other words, a payee signature is not ...
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2answers
406 views

Is there a real threat of so called “>50% attack”?

According to Bitcoin Wiki attacked who has majority of computing power of the bitcoin network can successfully do some nasty things such as potentially book double-spending or prevent transactions ...
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1answer
62 views

How the Bitcoin community will handle attacks on a Client's code?

I have some thoughts about the following scenario. The brightest future. The Bitcoin becomes a very popular and liquid currency all over the world. Some serious financial or political parties may ...
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1answer
435 views

What attacks are possible with a malicious bootstrap.dat?

The standard Bitcoin client normally needs to download the entire blockchain from the p2p network when first installed, but a shortcut is to provide it with a snapshot of the blockchain (at some point ...
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6answers
2k views

Is it possible to spam the bitcoin network with 'dust'?

Someone could buy or mine bitcoins, and send them in small transactions all day to spam the blockchain. Is this possible? And could this mean the end of the trust people have in bitcoin? edit: And ...
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3answers
271 views

Would it be feasible to attack the bitcoin network by buying and deleting large amounts of bitcoin?

Could a government, determined to stop bitcoins, just buy a lot of bitcoins and delete the wallet afterwards? Are the bitcoins gone then?
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2answers
202 views

Attack on bitcoin network with modified client?

Scenario: Mallory, Alice and Bob found block on their farm. They disconnect from internet, simulating split and change all of nodes in their segment to malicious. Malicious nodes decrease ...
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2answers
710 views

What happens if Bitcoin itself is obsoleted by another digital currency?

Unless Bitcoin is replaced with a Bitcoin-compatible currency, I believe that all holders of Bitcoin will be out of luck when the day comes that it is obsoleted by a superior system, as inevitably ...
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2answers
190 views

Government disrupting reception of bitcoins. Is it possible?

I was thinking of a very specific scenario: Suppose we have a new organization, let's call it "WikiLeaks2", which receives donnations mostly in the form of Bitcoins. Suppose a national government ...
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3answers
2k views

Why do pools get so often DDoS attacked?

In other words: who has incentives for attacking pools? Do you think it's the government?
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1answer
649 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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0answers
22 views

Could the target become unreachable? [duplicate]

As far as I understand it, the target T is a floating point number that is adjusted based on the moving average of the difficulty of some previous transactions. Mining a block happens when somebody is ...
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2answers
786 views

DDoS on big mining pools: a quick way to 51%?

Slush's Pool, the second biggest mining pool around, is currently down, allegedly due to a DDoS attack: News 16.04.2013 Pool is under DDoS attack. I'm working on recovering the service back to ...
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1answer
214 views

Can someone saturate the network?

Suppose I have 2 wallets and 1 bitcoin and I write a program to make transfers of 1 satoshi from one wallet into the other. No suppose I have 100 bitcoins. Wouldn't that saturate the network?
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2answers
768 views

Developments to prevent 51% hack [duplicate]

How might Bitcoin be made impervious from attack by large monied interests that could atttack with a brute force majority hashrate hack?
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1answer
977 views

Could a mining pool attack Satoshi Dice?

Is it possibile for a mining pool to attack Satoshi Dice? A strategy might be: bet on Satoshi Dice and if the bet wins, do nothing, if it looses, don't put the transaction in the block (try to double ...
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3answers
730 views

Is the minimum amount of money required to purchase >50% hash power equal to max worth of all existing bitcoins?

20 BFL Bitforce Mini Rigs (each, $30k) will give about 30THash/Sec hash power for $600k. That's way above 60% of hash power of then total 51THash/Sec. 10.694M total Bitcoin * $18.5 current mtgox best ...
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1answer
115 views

I'm developing on the Test network. Are there any “rules” or communication methods I should adopt?

I'm testing a C# port of the client on the Test network and need to test for a variety of conditions. Should I communicate to others regarding my actions on the network? If so, what method of ...
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2answers
425 views

What stops miners/nodes lying about what time a block was mined?

From what I understand, the difficulty required by the proof-of-work in bitcoin is a function of block history, specifically the average time between last ~2000 blocks, with the intention that its ...
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2answers
680 views

How much would it cost for a government to undermine Bitcoins?

Articles by for example the Economist stating that Bitcoins are being used for drug trading (Silk Road), I believe that the biggest risk to Bitcoins is that a government will pull a stunt similar to ...
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3answers
2k 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
231 views

How do mining pool payout methods affect the cost of executing a block withholding attack?

I'm wondering how each payout method (PPS, DGM, PPLNS, Proportional, etc) influences the cost of executing a block withholding attack. Does it matter how the payout method places variance between ...
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2answers
1k views

What is a block withholding attack?

How can a block withholding attack be performed, what would be its purpose and who is it a danger to? Edit: when I posted this I was thinking about withholding a block you mined in a pool. But ...
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2answers
3k 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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3answers
371 views

How can I assure my consumers they are actually paying the correct person? (prevent MITM attacks)

There are many network level attacks that give someone Man in the Middle ability to replace my Bitcoin address with their own. Since there is no way to cancel a transaction, and the best practice ...
5
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2answers
1k views

How can I find well-connected nodes?

If I am a merchant accepting 0-confirmation transactions I should protect myself against race attacks. Several resources state that I should configure bitcoin daemon to not listen for incoming ...
8
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3answers
788 views

Does the protocol ensures that private keys are unique?

There is a very very low chance for the same private key to be generated. (source) However, what happens when my generated private key matches a private key that is already used? Does the protocol ...
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3answers
358 views

What nodes are best for lessening the risk of loss from a race attack

A successful race attack is one where the payment recipient's node receives a spend transaction yet the next block that is mined has a different transaction that spends the same coin. Thus the ...
5
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1answer
700 views

What does a double spend look like?

What does a double spend look like? Can anyone link to an example on blockchain.info? Will invalid half of the double spend simply remain at 0-confirmations, or might it ever reach 1 or 2? Will the ...
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2answers
2k views

What is the story behind the “Linode problem”?

What is the story behind the "Linode problem"? How did the service become compromised and what has exactly happened because of it?
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1answer
421 views

What is the story behind MyBitcoin?

The name of MyBitcoin eWallet comes up quite often here and there. What is the story behind it and the attack on it they claimed occurred?
3
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1answer
120 views

Is an attack on a local bitcoind via an img or embedded flash viable?

In this thread on the Bitcoin forums it was suggested that a local attack on bitcoind might be possible through malformed img tags or (more likely in my opinion) through embedded flash. This also ...
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1answer
3k views

What is the story behind the attack on Coiledcoin?

A couple months ago I came across the news about Eligius pool being used to destroy an AltCoin called Coiledcoin. As I understand the miners of the pool did not know their hashing power was used in ...
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2k views

What can be done about the no-transaction block relayer (currently 71.123.170.150)?

An unknown major solo miner (currently IP 71.123.170.150), most likely a botnet, is relaying blocks with zero transactions. Two weeks ago this miner constituted ~15% of the network, now it constitutes ...