Is black-hat hacking haram?

I made a virus that mines Ethereum silently in the background. You can already see that this is just for money. But I plan on paying the victim back through donations. My target is some gaming station in my country, and they have really high-end gaming PCs. I noticed that they allow us to plug in our pendrive, so I just saw this as an opportunity. I've talked this out with my friends, but they all say it's haram without the slightest idea what Ethereum mining actually is, so please don't answer if you don't know anything about cryptocurrency mining. Some of my friends agree on this idea, but they say that I should use the money for good purposes, like charity, not just buying games on Steam. All I want is an expert's opinion on this. Is this haram, halal, or in between? Summary: -------- 1. I plan to use 50% of the money for donating to charity agencies 2. I plan to pay back the gaming station after I'm done reaching my goal