Can you sum up what happened in Intense? In our case it was not 51% attack of double spend. We had several types of attacks. First one was abusing vulnerability in difficulty algo which we were going to close - in the same day we put preparation on github there was an attack - having >51% hashrate they managed to temporarily lower the difficulty and got ~10k krb. in an hour. We decided that it's not worth rolling back chain. Aftherwards there were two spam attacks - spamming transactions with large mixins that were large in size and hard to verify so some nodes were crashing, after we set limit to max mixin they started to just spam so we had to set higher fee.
read yourself
https://intensecoin.com/2018/04/16/imminent-hard-fork-and-network-attack/
“As almost 6,000 blocks were stolen by the attacker(s), the blockchain will be rolled back to the last normal block before the attack started.”
As far as I understand blocks were actually mined by attacker due to exploit in diff algo. Read yourself:
“Most significantly, the attacker manipulated timestamps of the blocks to exploit a weakness in the difficulty calculation algorithm of the coin. This manipulation allowed the attacker to find about 8 days worth of blocks in several hours.”
Highly likely this attack was conducted via NiceHash.
By the way, Karbo after recent hardfork is protected against this type of attack.
“The Intense Coin blockchain will hardfork to version 4 in the next several days as the developers conduct testing. Version 4 will include several new features:
- Adoption of zawy12’s LWMA difficulty algorithm, which is much more responsive to hash power fluctuations. LWMA has been live on several coin networks for a few months. Zawy and the coin developers have worked out the bugs, and the algorithm has proven to be very reliable in testing and production.”
Karbo successfully adopted zawy12’s diff algo about a year ago. So Karbo is actually the first from these “several coin networks”.
