How can you be sure if he is not supported by bot or if he hasn't some means of influencing what cards are dealt or knowing what cards have been dealt to you?
Is there some poker specific cryptographic tool for that or you must just assume that system you are using to play is completely secure?
Basically, the online casinos are making so much money, they want it to be on the up and up so they can keep taking the rakes.
The major poker sites are well know and trusted and have proved themselves competent in preventing 'cheating' like what you describe. They're very good at all things security, and you can even get a RSA keyfob to log into your account much like some online banks.
If I were successfully researching poker bot I would not go public with this.
That said, there has been at least one major incident where one of the original employees of a poker site used a "superuser" account to see his opponents' cards at the high stakes tables and win lots of money. The players figured it out based on his statistically improbable win rate and an accidental release of the full hand history of one of his tournaments.
http://news.cnet.com/60-minutes-report-how-online-gamblers-u...
I particularly enjoyed this quote:
"This Grey Cat person was new. And at first, he seemed like a live one. He seemed terrible," Witteles remembers. "He seemed to play crazy. It seemed like he was giving his money away. Except the only thing was, he wasn't losing. He was playing in a style that was sure to lose, but he was killing the game day after day."
If skilled player possessed backdoor access to poker system and used it wisely, peeking in only from time to time when it's necessary and might go unnoticed he'd be rather undetectable.
In an online game, how can anyone be sure that information sharing is not taking place?
Collusion over a very short period of time from specific (and easily changed) IPs can make a lot of shared money - it's not clear how (and even if) online poker sites would monitor this.
They obviously won't catch all people colluding but they will catch most of them. And just changing IPs won't help much when they ban your account/payment details and you have to arrange another fake identity that checks out at a payment processor regularly.