Quote from: nanona on November 05, 2017, 01:26:43 PM

The network suffered an instamining attack for the past two hours (10:50-12:40 GMT) done over the mine77 pool. I think I saw something like 350kH/s at work. 50kH/s of which are the genuine permanent miners in that pool, so the attacker used appr. 300kH/s. During these hours we saw blocks 30208 to 30406 which was 198 blocks in 110min or 1.8 blocks/min or an average block time of 33 seconds. The normal rate would have been 36 blocks during that time, therefore 162 blocks (nearly 14,000 IRD) were mined in excess due to the not fast enough difficulty re-target on this blockchain.

I suggest the dev team starts to implement a more up to date diffculty re-target function. In the past Sumokoin (SUMO) and Masari (MSR) suffered the same fate of getting raped by nicehash idiots, i.e. centralized hashrate for hire. Masari then adopted the retargeting from SUMO which stopped these attacks. I consider these attacks equivalent to someone going into a restaurant, eating and then running away while telling the waitress that the invoice will be paid by the next customer.

This is exactly what will happen now since the difficulty is slowly (and delayed) adjusting upwards long after the attack has stopped, which means the genuine 24/7 miners which actually secure the network will mine against a high difficulty (which comes too late), will waste lots of electricity and get very few blocks, i.e. coins. They basically subsidize the coins stolen by the nicehash idiot. Yes, I consider it theft because the nicehash attacker is not willing to mine at the difficulty his hashrate generates. That's why he ran away after a short time and doesn't mine 24/7, knowing exactly that the invoice (difficulty) is presented only after the fact and he can leave it to the other miners.

The difficulty re-target will always be a trailing indicator because it works based on the block times found previously. But it must be such that it can react very quickly on such hashrate attacks and drive difficulty up immediately when the blocks start flying. Once it stops, it must equally quickly adjust difficulty down of course. Other coins have solved this very well and this coin should upgrade as well on a coming HF. After all the block time is the heartbeat of the network and it must be predictable and constant. It is additionally controlling the issuance of the coins (inflation) and this must be fully under control and resilient to such nicehash attacks. Hence why I always recommend that pools do not accept nicehash workers. Nicehash is the exact opposite of a decentralized ledger and currency mined by decentralized miners. It's a centralized service which should be blocked wherever possible.

This is a very valid and important point. It has been happening with all CPU friendly coins, botnets like nicehash screwing up the diff. I don't believe the original dev cared enough to actually consider this, but we do! We will get on this upgrade immediately and begin the transformations. It may not be done quickly, but we will get it done. Thank you for pointing this out.

Windozxpert

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