Bitcoin Forum

even with >51% hash power, how the attacker would be able to build a longer chain with the 10 minutes interval?

the original chain would have less power, but the difficulty would adjust.

hmm they would be able to make a longer chain because the difficulty takes time to adjust, making the honest chain unusable. This is very bad, but I dont see how they can create a longer chain after the difficulty adjust.

why you are connecting the two thing? i can't really see how they are related, if there is a longest chain that is the legit chain, if the diff need to adjust the atatcker can still do all the attack with a 51% of the nethash, there must be away to identify the legit chain without basing the thing on the hash but on the legitimacy of the block maybe

Don't mix two things. I can't generally perceive how they are connected, if there is a longest chain that is the genuine chain and other stuff etc. May be writemypersonalstatement (http://writemypersonalstatement.net/) can help you.

also what the OP say doesn't make sense, why the diff should reajdust when there was no increase in hash, a 51% can be achieved with 51% of current hash mining on a single pool, without increase the total hashrate

also if you add only 51% of the current net you can't do 51% attack, because you would have 33% of the net you need to add 100%+, the diff increase in this case means only that the new attacked will make half of the block and nothign else

Theoretically, it is possible to hold more than 50%, but in reality it is very unlikely that it will happen, only virtual transactions can occur and not confirmed by the network.

You need to mined 2016 Block before difficulty retarget...

So even if you have the control over 51% of hash power you will not kill bitcoin. The community could come to some agreement about what the honest chain was before the attack and may be add a new hash function to avoid it again...

The 51% actually just gives you a higher possibility to mine a block before everyone else.... So that attacker may have the opportunity to hide the newly mined block, make changes to the block, double spending or start working on the subsequent blocks earlier etc.

You can actually perform the attack with any % of hashing power lower than 51%, but the probability of success decreases with less hash power. This is why BU will not HF with a 51% hashing power, but 75%.

those attack are only possible with some lower numbers of confirmations like the finney attack, they ar enot possible with 6 confirmations, but 51% ensure a proper attack even with 6 confirmations

What do you call the current miners mining their own transactions and avoid legitimate users transactions? IMO some of the biggest pools are attackers/ hostile/ malicious and are not really contributing anything to the community, they just want their profit.

Now I've got a question, how can we punish such pools? how can we cause a pool's block to get rejected or orphaned?

Fake Confirmations... That's the whole thing  :-\

Which pools? Hard proof or at least quotable suspicious actions by them leading to this theory?

you can actually do that?

i dont think anyone can get enough mine power to achieve this

Ha... it did happen before!

Besides the first 1-2 year when there was only a few miners around, 51% was actually achieved by GHash.IO mining pool in July 2014, Everyone was worry about the attack and moved their hash power to other pools. Sadly, GHash.IO is no longer around.

If you can resist doing it if reality is not possible then it happens, only transactions that will make and it's just a transaction that will not confirm.