According to the official announcement made on April 2nd, 2018, Google will no longer accept cryptocurrency mining extensions to the Chrome Web Store. The statement cites security issues as the main reason for the change in the policy:
“As the extensions ecosystem continues to evolve, we remain focused on empowering developers to build innovative experiences while keeping our users as safe as possible.”
Already available mining extensions will be deleted from the Chrome Web Store in two months. The ban won’t affect other blockchain-based extensions.
There indeed has been a rise in extensions which provide users with false information about their intended purpose and run mining scrips in the background without user’s approval.
According to the Chromium Blog, these mining scrips vastly increase the CPU load and power consumption. The previous set of policies considered the miming application legitimate if the purpose of the app was explicitly stated. It turned out that 90% of submitted apps failed to comply with the imposed standards. Google stated:
This policy is another step forward in ensuring that Chrome users can enjoy the benefits of extensions without exposing themselves to hidden risks.