Questions tagged [checkpoints]
23 questions
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What are checkpoints?
I often read that checkpoints protect the network from a 51% attack because an attacker cannot reverse transactions made before the last checkpoint.
How exactly does this checkpoint mechanism work? And who creates the checkpoints?
nmat
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Why does Bitcoin no longer have checkpoints?
I've read that checkpoints in Bitcoin were removed because they were not preventing any meaningful attack.
Why should a regular checkpoint not prevent majority attacks? For instance, if a checkpoint is made every N blocks and (for example) 3/4 of…
Anon
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Which blocks get to be checkpoints?
Which blocks get to be checkpoints, and why is one block chosen to be a checkpoint, rather than another block? And where can I find a list of checkpoint blocks?
user189
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What alternatives are there to hardcoding checkpoints into the Bitcoin client?
Checkpoints seem like a crucial part of the security & validation apparatus in Bitcoin. Is there a written policy in place, among the developers defining the maximum interval between checkpoints?
What happens when the Bitcoin client becomes mature…
gosmond
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51% attack and rewriting to the latest checkpoint
This is not a question about the consequence of a 51% on the price nor as to the motivation of the attacker. Let say we don't care that it's not realistic and we don't care that the attacker wouldn't be rational.
Let's just assume an attacker has…
Cedric Martin
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Why is it important for checkpoints to contain well-formed blocks?
In the source code of the standard client, checkpoints.cpp has this comment:
//
// What makes a good checkpoint block?
// + Is surrounded by blocks with reasonable timestamps
// (no blocks before with a timestamp after, none after with
// …
Nick ODell
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Do all Bitcoin client enforce checkpoints?
The core Bitcoin client has a list checkpoints - blocks where it will only accept a particular block header. This means that if someone builds a blockchain with more work that does not include these checkpoints, Bitcoin Core will not accept…
Nick ODell
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Why does the daemon require peers in order to start mining?
I wanted to start mining Bitcoin from the genesis block, so I cloned Bitcoin and removed the checkpoints. Then I compiled and started up the daemon. I wasn't connected to any other peers, however, so it wouldn't let me mine. I did ./bitcoin-cli…
morsecoder
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Do checkpoints in the block chain help to avoid a 51% attack that rewrites the entire blockchain?
I have read sometimes in the web, that in the blockchain are checkpoints, so that an 51% could not the blockchain before that checkpoint even with over 51%. Is this true?
In this answer this is missing completely:
Can an attacker with 51% of hash…
user54512
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Why are broadcast checkpoints considered bad?
warren, a LiteCoin dev, said of Peercoin:
Good Luck Removing PPC's Centralized Checkpoints
Regarding PPC... these amount to empty obfuscating defensive excuses. Sure he wants to remove the broadcast checkpoints. Novacoin's Balthasar made similar…
Claudiu
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How to build a bitcoinj checkpoint file
How can I build a bitcoinj checkpoint file
like the Bitcoin-wallet checkpoints?
Gordon
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How does a node find the active chain?
Let's say a user joins the Bitcoin network and downloads the latest state of the blockchain (all blocks, which includes the forks/uncles). How does this user find/determine the active blockchain on which they should build upon? I'm not asking about…
E. Kruminis
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Is Block Finalization a valid development to remove the threat of 51% attacks?
https://www.reddit.com/r/btc/comments/bq8cqo/btctop_currently_has_51_hashing_power/eo2p4md?utm_source=share&utm_medium=web2x
A recent comment from a Reddit user in response to BTC.top acquiring 54 of the Bitcoin Cash has hate noted that a Block…
AdaptiveAnalysis
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Is there anything I can do to speed up the synchronization of litecoinj?
I am using litecoinj which is forked from bitcoinj but compared to bitcoinj, the wallet creation and block synching is slow when using litecoinj. So, I searched for a solution and found a post that suggests to download checkpoints in a file and pass…
Aman Vyas
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What kind of attacks do exactly check-points prevent?
I'm aware of this post and this one.
If it's used to prevent an attacker from forking old blocks (or chain), then a client can detect it because the fork length would be shorter than the length of the existing (correct) chain.
Question: What…
user153465
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