Quote from: xtraelv on January 21, 2019, 11:43:14 AM

Quote from: Timelord2067 on January 21, 2019, 11:25:48 AM

@xtraelv Muchly Wow!

As a non-employee you would lecture now about multiple 51% attacks you know nothing about?

Held to ransom is what Cryptopia did to the SexCoin community and to about another 100+ alts coins similarly affected. And as @einsteinium correctly points out, there were multiple attacks over many weeks over many, many alt coins.

You should read up on these posts before you click reply.

How do you propose that an exchange detects 51% attacks ?

(Keep in mind an exchange wallet could contain up to a 100000 public and private keys and take a week or more to sync.) Each coin would have at least 5 or more wallets and I think they list around 400 coins.

Why did the coin devs not alert them about an attack on the blockchain ? Surely something with $?? millions in marketcap is not left unattended or unchecked for blockchain exploits ?

Bitcoin for instance tracks all the ophaned blocks https://www.blockchain.com/btc/orphaned-blocks

Keep in mind that in a 51% attack the blockchain held balance is being exploited and manipulated - not anything on their exchange servers. Confirmations come from the blockchain nodes.

A 51% double spend attack alters the balance held on the blockchain well after the blockchain has provided the set confirmations that (I'm assuming) have been agreed upon by the coin devs and the exchange as being adequate for that coin. (If the confrimations were inadequate then why didn't the coin devs alert them. If the coin network devs were aware of the attack why did they not alert them - which are both a listing requirement in their TOS).

I am not aware of the full extend or specific details but I spent quite a bit of my spare time analyzing some 51% attacks for the article I wrote.

Could you give me the link to the article you wrote about the 51% attacks? I would like to understand how this happens. Thank you