Remark: I normally don't mention BETA programs... but this development is highly interesting. IF you decide you want to try this (or any other) BETA program, realize you are proceeding at your own risk.
https://securityintelligence.com/news/opera-offers-first-built-in-cryptojacking-protection-tool/
According to ZDNet, the beta version of Opera 50 is the first major browser to offer a built-in mechanism that blocks cryptojacking, a new form of malware that leverages the victim’s computer to mine cryptocurrency without permission.
The new antimining tool, called NoCoin, is part of the ad blocker function in Opera. It is disabled by default but can be enabled through the Settings or Preferences page. According to an Opera blog post, the tool blocks cryptocurrency mining scripts just as an ad blocker would disable banner ads and pop-ups.
Without a tool such as NoCoin, a cryptocurrency miner might go undetected until the central processing unit (CPU) usage dramatically increased for no obvious reason, preventing the victim from executing his or her own programs.
