Apple has put restrictions on apps that mine cryptocurrencies using device processing power, specifically disallowing such programs in its App Store.
In an update to the Hardware Compatibility section of its developer guidelines, Apple said "apps, including any third party advertisements displayed with them, may not run unrelated background processes, such as cryptocurrency mining."
Apple's concerns about cryptocurrency mining stem from power efficiency.
"Apps should not rapidly drain battery, generate excessive heat, or put unnecessary strain on device resources," the company stated in the paragraph banning cryptocurrency mining processes from running in the background.
However, cryptocurrency mining apps that don't use device processing power but instead run in the cloud are allowed in the App Store.
Wallets coded by developers enrolled as an organisation are also allowed, as are apps that facilitate transactions or transmissions of cryptocurrencies, provided these are offered by the exchanges in question.
Apple further disallowed cryptocurrency apps that reward users for completing tasks such as downloading other apps or coaxing other users to do the same or to make social media posts.
The company also warned developers that any apps that facilitate initial coin offerings (ICOs) and cryptocurrency futures trading must come from established banks and approved financial firms.
ICOs must comply with "all applicable laws", Apple said.
In February this year, a researcher discovered 4275 government sites, including many in Australia, had been hijacked to run the Coinhive cryptominer to generate Monero coins on users' machines.
The hijackers had compromised the Browsealoud accessibility library that reads out web pages to blind and partially sighted people.
One macOS app, Calendar 2, in March this year openly offered users the option to run a Monero cryptominer in return for a free, no frills version of the program.
After the cryptominer was found to contain buggy code that made CPU usage on users devices spike, Apple pulled Calendar 2 from the macOS App Store.
Eventually, the developer of Calendar 2 released a version without the cryptominer, citing the non-openness of the library that was used, and the bugs that caused excessive processor usage.