I've just participaded in one game, in which I'm 90% sure (player's behaviour strongly suggested it, but obviously I can't get any proof). It looked like someone being logged in as 2 or 3 users (not sure about the 3rd). None of them attacked each other. That 3rd player didn't attack during the whole game, because he was cut off by 1st player. He just clicked on "end turn" for the whole game, way after he accumulated 32 surplus points. 1st and 2nd were neighbors and didn't attack each other even once, even though they became the strongest ones quite quickly (they just finished off the next strongest player one by one). Out of curiosity... do you at least store ppl's IPs? Here are the nicks (just for "research" purposes, if you do store IPs): TEH_NICK, Axiom, Axis (3rd, uncertain).

Are there any anti-cheating measures?

Here are couple proposals:

* save IP and cookie identifier for each session that's opened by a player. cookie - set a browser cookie IF THERE WAS NONE BY NOW. cookie should contain some unique string (I called it "cookie identifier" before).
* some possible rules:
* users can't play together if they have the same IP right now.
* users can't play together if they have the same last byte of IP.
* users can't play together if they had the same IP at least once during last x days (for example in the last two weeks).
* users can't play together if they had the same cookie at least once during last x days
* let people see the most recent IP of any user in his profile.
* let people report abuse. if you do it right, you could automatically weed out many cheaters (for example "someone is banned if he has at least x reports in two weeks AND he's been reported after at least x% of games within the last two weeks").
* do not reveal your anti-cheating measures. Cheaters don't need to know what they're fighting against.

This are just some ideas... there could be more (like for example comparing md5 hases of passwords or - if you don't hash passwords - you could do something like calculating levenshtein distance.

Anyways - kdice is a great game!