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Questions tagged [checkpoints]

The tag has no usage guidance.

0
votes
1answer
30 views

Do checkpoints affect initial chain sync time?

I've seen some guides that suggest that initial sync time for a new full node can be accelerated by setting checkpoints: false but I don't understand why that would be the case. My thinking is the ...
4
votes
1answer
572 views

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 ...
5
votes
2answers
977 views

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 ...
1
vote
1answer
234 views

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 ...
1
vote
1answer
142 views

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 ...
1
vote
0answers
72 views

Reset bitcoin blockchain checkpoint to mine 0th block [duplicate]

I want to start a new block chain and mine the 0th block, but I guess the hardcoded checkpoint in chainparams.cpp won't allow that. I guess I need to reset the checkpoint hardcoded as follows before ...
2
votes
1answer
258 views

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 ...
2
votes
1answer
341 views

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 ...
0
votes
1answer
736 views

What values should be initially assigned to Checkpoints for a new Genesis block?

I have created a new Genesis block. What values should be assigned to these fields? namespace Checkpoints { typedef std::map<int, uint256> MapCheckpoints; struct CCheckpointData { const ...
4
votes
1answer
506 views

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 ...
2
votes
1answer
207 views

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 ...
0
votes
2answers
244 views

Why can't I create a fork of BTC that has no difficulty changes so I can premine the rest of the coins?

I don't want to necessarily do this, but what prevents this scenario from being possible? [just timestamps and a difficulty modifier alone? - if that's the case then why can't I modify the client to ...
2
votes
2answers
1k views

How to build a bitcoinj checkpoint file

How can I build a bitcoinj checkpoint file like the Bitcoin-wallet checkpoints?
7
votes
2answers
618 views

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? ...
4
votes
1answer
215 views

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 ...
10
votes
2answers
2k views

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?
34
votes
3answers
7k views

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? ...