Quote from: Barek on February 12, 2014, 12:58:57 AM

Quote from: FeedbackLoop on February 12, 2014, 12:55:13 AM

Quote from: Barek on February 12, 2014, 12:47:35 AM

This changes nothing on the usual practice that once a transaction is part of the blockchain it is safe to trust it. A 51% attack actually rewrites the blockchain.

NO it actualy doesn't: https://en.bitcoin.it/wiki/Attacks#Attacker_has_a_lot_of_computing_power

Sorry for the tangent, second time that 51% BS was creeping in, and thank you DandT.

Uhm, yes, it does? With enough time and >50% you can start at any point in the blockchain and eventually overtake the current one.

That is why there is the 6 confirmations thing. The more confirmations there are the harder it is to create a malicious fork. With >50%, all bets are off.

You made it sound both as if the attacker could re-write past blocks (before he managed to compute a lot of blocks in a row) and that he could do whatever he wanted with the blocks he wrote and both are not true. I felt I should shortly dispel that idea in this thread due to the potential readership. But please lets not derail this. I will stop responding to this off-topic. Thanks again DT.