How does Lichess verify that a User is cheating?

I just got some points back because apparently I had lost to a cheater. How does Lichess know for sure that that person was cheating. I looked back at the game I lost to them and they weren't even played against that user and they hadn't even played perfectly, I just played a lot worse.

So now I'm wondering, how can Lichess tell for sure that someone is using computer assistance?

We have about 20 mods going through games. Both from player reports and from tools that generate alerts for suspicious games.

Sometime it's hard to see the reason, but the mod tools gives a lot of insight that regular players don't have access to.

This seems like a good question and new information. It may be worth adding this to the Q&A.

I´´ m quite new to the platform. Last month played and won against a similar rated opponent. He challenged me for a rematch and beat me in 27 movements. No blunders, no mistakes and no impresicions from his side. It was clear to me that he was cheating.
Last week i received increase in points (but no info on who was the cheater). I guess such a unbelievable level in playing rang some bells and admins did their job. However i did not raise any flag on the user because i dont know how to.

Imo there is no need to inform everyone about which user that was marked. I think it would only lead to an increase in public shaming.

You can report a user by either:

• going here: https://en.lichess.org/report
• going to his account and pressing the triangle in the top right corner of his profile.

Revealing how cheaters are caught will make it easier for them to go undetected. So I would prefer for the information not to be revealed. I mean, some of the clues are obvious but I suspect there are lots of sophisticated extra methods that are less so.

Engines will catch you using an engine, mods verify.

This is just my guessing on how they do it.

Think of it like this. Every game you play is run through an engine. Simple question is asked of the engine. "Is this a human, or is this a machine playing?" If it marks it as a machine playing then the game is taken, and tagged secretly. The engine gives a % number on how likely it is an engine. The first "This is probably an engine" from an engine will probably not get you tagged a cheater. Get a few in there though, and the engine will make a case for it, then it goes to a mod. The mod reviews what the engine has brought it, all these red flagged games, and then puts a cheater tag on the player.

@lurarose Engines will catch you using an engine, mods verify.

Yes, it seems that all of the identified cheaters "decoy", which was supposed to detect fraud. The suspicion may occur only upon complaint by the offended player. If you never complained about fraudsters who are cashing in at Your expense, probably, these crooks continue to cheat.

#3 What is the new information?

I think they have a look on reported games and they decided he or she is cheater or not.