A cyber security expert says there’s really no way to be sure if Cowboys Casino has plugged the security holes exploited by hackers last year.

Data from a 2016 hack was leaked online Sunday by the hackers, who said they would release more personal information unless the casino fixed security flaws.

The casino said problems were addressed last year, and there have been no hacks since that time.

University of Calgary professor and author Tom Keenan said the only way to know that for sure is for the hackers to test the claim.

“Your IT company can tell you anything. ‘Yeah we plugged all the holes.’ There just has to be one hole left for the bad guys to get through,” said Keenan

The message left with the leaked data said the casino would have a week to address its security problems, meaning more data could be leaked this coming Sunday.

Casino general manager Tyrone Waite told Metro he couldn’t comment on whether or not the hackers had made any financial demands of the casino, noting that Calgary police are still investigating.

Keenan said examples of hackers exposing flaws in security just for the sake of improving security are not unheard of.

He pointed to the case of hacker Chris Roberts, who was arrested after allegedly hacking into a commercial airliner’s control system via the entertainment system.

He said all casinos might benefit from limiting the personal data they keep on running computers, and look at offline storage options instead.

“If you can’t protect it, you shouldn’t collect it. That’s kind of a motto in privacy,” he said.