Half a billion internet users may be unknowingly mining cryptocurrency

According to new research, the rapid expansion of scripts which allow website owners to profit using the CPU of visitors’ machines to mine cryptocurrency could mean that hundreds of millions of PCs are already being slowed down by the process.

Cryptocurrencies are supported by cryptocurrency mining. This requires heavy use of computing power to verify cryptocurrency transactions and add them to their public ledgers by crunching through computationally expensive mathematical problems. Being first to solve these problems earns financial rewards.

Now, research conducted by ad-blocking company AdGuard has estimated that half a billion internet users could be using their CPU to mine cryptocurrency in the background, mostly without their knowledge As many as 220 of the most popular websites run mining scripts, with a reader base of approximately 500 million. The website owners, and not the users themselves, tend to profit from running these scripts.

“220 sites may not seem like a lot,” the researchers wrote. “But CoinHive [a cryptomining script] was launched less than one month ago on September 14. The growth has been extremely rapid: from nearly zero to 2.2 per cent of Alexa’s top 100,000 websites.”

US websites were the worst offenders, the research suggested, with 18.7 per cent of websites running cryptocurrency mining scripts. Media streaming, file sharing and pornographic websites were most likely to include the scripts.

According to Ad Guard, these scripts hijack the CPU of a device, and reserve part of it for cryptocurrency mining, significantly slowing the machine’s performance and mounting significant energy bills.

Cryptocurrency mining can be a lucrative business, although it comes at great energy cost: according to Digiconomist, mining for Bitcoin alone accounts for just under one per cent (0.09) of the world’s electricity consumption. A website which – by legitimate or devious means – uses its users’ electricity to mine can do away with adverts or subscriptions, covering its running costs with the proceeds of cryptocurrency mining.

Last month, it was reported that Showtime and other websites had been surreptitiously running a script on their websites which used the excess CPU of its users’ devices to mine cryptocurrency. That particular script, CoinHive, was designed to mine an open-source cryptocurrency, Monero, at the expense of users.

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