Questions tagged [attack]

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.

Filter by
Sorted by
Tagged with
0
votes
0answers
15 views

Mathematics behind sidechain SPV skiplist proof attack

I am reading about verifying SPV proofs of a sidechain where we don't want to verify all N blocks of the sidechain. In the example instead of verifying that each block meets the target difficulty (...
0
votes
1answer
35 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 ...
0
votes
1answer
42 views

What is the SPV Mining Exploit?

Can anyone explain this simply? I am not finding enough explanation exactly on this type of attack. If possible, add some additional reading to your answer so that I can understand more.
2
votes
1answer
66 views

attack bitcoin through writing data directly into output's scriptPubKeys

In this post, Steve Ellis wrote : "[...]Writing data directly into a output's scriptPubKey is not prunable[...]where as non-prunable outputs will forever create bloat and slowdown the set ...
0
votes
2answers
36 views

What are some potential scenarios that a state actor can harm bitcoin if they control more than 51% of the hashing power?

As reported recently, China controls more than 51% of the hashing power and just in one province in China controls 54%. Assuming China has bad intentions and forces all these mining operators to ...
0
votes
1answer
28 views

Bitcoin 51% majority miner attack - question on the role of user activated soft forks as defense tactic

If one mining entity has alone 52% hash power of the overall network, then this party can block transactions for example and try to "build" up a forked, longer chain while time passes, right?. As I ...
1
vote
1answer
209 views

Can i trace a hacker by collecting data from Bitcoin api?

In Japan, MtGox, the biggest bitcoin exchange went down and went bankrupt due to hackers. So I'm working on a project in my College to enhance security of bitcoin transactions using the data mining ...
0
votes
2answers
2k views

Hacked bitcoin account.

I believe that my account was hacked: a "send" transaction occurred on my account an hour ago and I lost $62 without my raising any transaction. The transaction is still unconfirmed, how do reverse it ...
0
votes
1answer
61 views

Is OP_RETURN dangerous for Bitcoin?

Please explain something about OP_RETURN to me? https://bitcointalk.org/index.php?topic=1166928.0 I saw a discussion that the contents of OP_RETURN can open the value of access to the private key. I ...
0
votes
0answers
27 views

How could an attacker with more than 50% of full nodes hurt the bitcoin network the most? [duplicate]

According to Luke Dashjr's stats there are currently around 61.000 bitcoin nodes supporting the bitcoin network. https://luke.dashjr.org/programs/bitcoin/files/charts/historical.html What if an ...
19
votes
6answers
7k views

51% attack - apparently very easy? refering to CZ's “rollback btc chain” - How to make sure such corruptible scenario can never happen so easily?

I was shocked to see binance CZ comment to literally "roll back" the bitcoin chain by just "calling" in some favors from "friendly" Asian miners . This ONE person could effectively do it??? I mean ...
0
votes
1answer
645 views

How to find one private key from the list of 15 million public keys for the sake of experimentation?

Recently found a list of compressed public keys. The total number of 15 000 000 public keys. Practical for all compressed public keys Balance: 0.000100 BTC I do not set malicious goals. All just for ...
0
votes
0answers
14 views

Regarding 51% attacks in blockchain [duplicate]

Can anyone tell me, What is 51% attack in blockchain how this attack is prevented
0
votes
2answers
738 views

How does changing transaction data in a block change the hash of previous block?

I am reading this article, within which it mentions that "Imagine this for a second, a hacker attacks block 3 and tries to change the data. Because of the properties of hash functions, a slight ...
2
votes
2answers
75 views

Probability an honest node finds the next block vs. probability the attacker finds the next block

I am trying to understand Satoshi's paper [1]. On page 6 of the paper, he calculates the probability that someone can attack the blockchain from z blocks behind. He begins by defining: My question: ...
5
votes
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?...
3
votes
2answers
306 views

To what extent does asymmetric cryptography secure bitcoin transactions?

Is there a specific attack or bug which asymmetric cryptography prevents during bitcoin transactions?
0
votes
1answer
59 views

Possibility of a DDoS attack

Theoretically. This is not a mechanism of any kind of attack, but It's about the "lost" coins. May be. It is just for an educational experiment. What if someone has the ability to send transactions ...
33
votes
2answers
14k 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".
2
votes
1answer
103 views

Is this a collision attack or a 2nd-preimage attack?

This question revolves around Bitcoin Optech newsletter #51 (1) and an email thread from the bitcoin-dev mailing list (2). I asked the same question in a reply-email of the newsletter and the response ...
1
vote
2answers
112 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?
0
votes
1answer
64 views

How to re-secure a multisignature wallet if private key is stolen

Here are two attack scenarios on bitcoin private keys: 1) Assume that, BitCorp has just noticed that a Mallory has just compromised one of their servers holding their Bitcoin Private keys. Luckily,...
1
vote
1answer
55 views

What are the consequences if I spoof an IP address in the node_announcment message?

According to BOLT 07 the node accountment message looks like this: type: 257 (node_announcement) data: [64:signature] [2:flen] [flen:features] [4:timestamp] [33:node_id] [3:...
4
votes
1answer
82 views

Malicious full nodes causing denial of service attacks

To control >51% of the mining power in bitcoin is impractical due to the immense investment that will be required. Also, The Bitcoin Core client has DoS protection against malicious nodes forwarding a ...
0
votes
1answer
25 views

What stops miners from no longer submitting failed hashes to the network, to reduce the difficulty and block time?

As I understand it, the difficulty adjusts based on the hashrate to keep the block times at 10 minute intervals. But if Alice and Bob are the only ones mining on the network, what's to stop Alice from ...
6
votes
1answer
882 views

What is time warp attack and how does it work in general?

I am trying to understand the recent time warp attack on verge but since the attack is universal across all POW block chain i figure I could also ask here since people here are .. more knowledgeable. ...
5
votes
2answers
619 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 ...
0
votes
2answers
1k views

What prevents an attacker from doing DDOS on bitcoin network by sending billions of transaction to himself?

I know that transacion fees on low-priority transactions adds additional cost, but what if an attacker uses a lot of 0.100001 BTC transactions, so he doesn't have to pay the fee, because transactions ...
4
votes
1answer
72 views

Serialized transaction bigger than the actual transaction object? CVE-2013-4627

I'm surveying old Bitcoin DoS vectors and came across CVE-2013-4267, for which there appears to be little public information available. This thread should shed some light on this CVE. There's a ...
10
votes
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 ...
4
votes
2answers
764 views

How does the Bitcoin network deal with bad actors?

Can someone explain at a high level how the network deals with bad actors (either intentionally (ie- attacker) or unintentional (ie- misconfigured node or a node running outdated code, forked code, ...
1
vote
2answers
35 views

What happens when the verification of a manipulated transaction fail?

If a malicious miner changes the amount in a given transaction, the hash value of the block changes. Thus, he has to find the required hash value again in that block. Let's say he successfully found ...
1
vote
2answers
380 views

Set up a Bitcoin full node: static or dynamic IP address?

I am trying to set up a new Bitcoin full node and my institution ISP is trying hard to not give me a static IP address for this purpose. I guess because of the concern that the node will be DDoSed, ...
3
votes
1answer
163 views

Bitcoin is attacked by China miners by screwing with the network, what will Bitcoin do?

There was a report recently (https://arxiv.org/pdf/1810.02466.pdf) that stated that China controls 74% of the hashing power. They can choose to collude and attack the network by either doing a 51% ...
4
votes
1answer
105 views

POW based blockchains systems Majority Attack

TL;DR: With only 30% of network power a Majority Attack is possible and profitable. Am I missing anything? Generally speaking, blockchains based on Proof-of-Work authentications are using amount of ...
8
votes
1answer
1k views

What prevents similar time-warp attacks in Bitcoin as happened to Verge?

Right now (may 2018), Verge (an altcoin with proof of work) was attacked by time-warp attack. More can be read here https://blog.theabacus.io/the-verge-hack-explained-7942f63a3017 What exactly ...
3
votes
1answer
70 views

Why was this transaction accepted?

In testnet, txid:fb7a8658ec015133e36e2cf7ddf7e8c887c3a5becec2f30f24ebfe43e72f4b59 transaction has two inputs. This two inputs indicate the same txid and vout, ...
2
votes
1answer
178 views

Is there a limit to how many blocks can be rolled back from a 51% attack?

I was wondering if we where to ever face a 51% attack is there some sort of limit as to when the longest chain doesn't matter? For example if I owned 51%+ of the network, mined 1000 blocks privately ...
1
vote
1answer
49 views

Possibility of broadcasting new block to only a fraction of honest nodes?

Consider in a block-withholding attack (aka selfish mining attack), attacker after creating a new block decides to broadcast this new block only to a fraction of network, such that eventually only a ...
1
vote
3answers
80 views

What prevents DoS based on near-valid block timestamps?

Upon receiving a newly mined block, the block timestamp validation is performed here: https://github.com/bitcoin/bitcoin/blob/master/src/validation.cpp#L3263-L3270 Q1: As for the second check (block ...
1
vote
1answer
53 views

Mining Theory: A theoretical mining based attack

Okay, so, here is my scenario: Imagine a group of miners who are mining a coin are responsible for a large portion of the hash rate on the network (let's say not quite 50%). Looking at the parameters ...
15
votes
2answers
5k views

Why do we call it a 51% attack instead of a 50% attack?

From the Bitcoin paper: p = probability an honest node finds the next block q = probability the attacker finds the next block qz = probability the attacker will ever catch up from z blocks behind qz ...
2
votes
1answer
175 views

Hypothetical Scenario - Address collision with address with already confirmed outgoing transaction

In a typical case of finding a collision with an address, as long as the private key provided has a consistent public key that hashes to the address, then the coins in that address can be spent. The ...
5
votes
1answer
90 views

Can corrupted unspent transaction outputs list leading to higher than expected fee be seen as an actual threat?

Let's imagine, an attacker managed to corrupt your local list of unspent transaction outputs (or a blockhain explorer you use) in a way that certain unspent transaction outputs seem to hold less coins ...
0
votes
4answers
750 views

How much computing power is required to bruteforce a Litecoin private key in reasonable time?

Say I want to break a Litecoin private key having the public key using brute force. How much computing power is required for that? Does any hardware exist which can find a matching private key in, say,...
1
vote
1answer
52 views

How prevalent are coin attacks with botique altcoins?

I have deployed several altcoins using various PoW algorithms on my LAN for my buddies and I to mine/learn from. We ultimately want to go the distance of deploying an altcoin to the world, writing the ...
0
votes
1answer
33 views

What stops people attacking my new coin?

Say I just made a new altcoin. I mined it for a few days at some reasanoble difficulty - 2000 for example. I got to the 10 000th block and I am happy with my premine and network. Then, an attacker ...
10
votes
3answers
4k views

Why can't mining pools provide fake transactions within the generated blocks?

Suppose Alice wants to add a fake transaction where she receives X ammount of BTC. I understand that in order to add that transaction to the blockchain she would have to compete against all the other ...
3
votes
1answer
147 views

How does headers-first prevent fill-disk attack?

Checkpoints prevented an attack where a node could mine many many low-difficulty blocks from an early point in the blockchain and serve those blocks to syncing nodes who would see their disks fill up. ...
0
votes
1answer
125 views

What exactly is selfish mining?

What is a selfish mining attack MonaCoin suffered from?