While the cryptocurrency trend kicks into high gear for legitimate purposes, North Korean hackers are also capitalizing on the digital tokens by hijacking computers to mine for cryptocurrencies, according to Bloomberg.

A hacking group within the reclusive regime has been leading the effort as the country looks for new ways to generate money while international sanctions continue to strangle its more conventional means of generating revenue.

The hacking unit, known as Andariel, reportedly took control of a server belonging a South Korean company in the summer of 2017 and used it to mine for Monero, a popular cryptocurrency that touts its privacy features that make it nearly impossible to trace the origins of transactions.

The hijacked server was allegedly used to mine for about 70 Monero coins, which are valued at about $26,000 at the time of publication. The North Korean hackers appear to prefer to operate in Monero, which has proved to be easier to hide and use to launder funds than other cryptocurrencies like Bitcoin.

Like Bitcoin, Monero uses its network of miners to verify transactions on the blockchain, a public ledge of activity. However Monero mixes its transactions to make it harder to trace funds back to their origin and takes steps to hide recipients of funds.

Andariel has reportedly been busy chasing cryptocurrency at every turn, and has generated much of their digital token stash by taking over computers and using their resources for mining. The mining process uses computer’s processor to solve complex mathematical equations, which in turn releases coins as a reward for contributing the resources.

Finding that computing power to mine for Monero and other cryptocurrencies is an important part of the equation for the hacking group, as it requires a significant amount of resources to mine the tokens.

While it’s possible for a person or group to mine for currency on their own machine or machines, the process is cost-prohibitive. A report last year from Digiconomist estimated that it requires about 215 kilowatt-hours (KWh) to process a single Bitcoin transaction. The average American household consumes 901 KWh per month, meaning a single Bitcoin transaction requires the same amount of energy that it takes to keep the lights on in a home for about a week.

According to South Korea, their neighbors to the north are also the prime suspects for ongoing attacks that have targeted cryptocurrency exchanges located in Seoul. The attacks have been happening since at least April 2017.

The alleged attacks on the cryptocurrency exchanges are just some of the cyber crimes North Korea has been accused of in the past year. The country was also pinpointed as the likely culprit of the WannaCry ransomware attack that affected more than one million machines globally in 2017. The attack demanded a ransom of Bitcoin be paid in order to unlock files that the malicious software encrypted and made inaccessible.

The tactic of hijacking computers to mine for cryptocurrencies is not limited to North Korean hackers. It has also been used by a number of websites, browser extensions and other add-ons to hijack the processing power of users’ computers to generate digital currencies for attackers. The tactic is referred to as cryptojacking.