The most popular cryptocurrencies mined by malware were Zcash and Monero, according to Kaspersky. This is noteworthy, because it reinforces the notion that mining Bitcoin, the most popular and valuable cryptocurrency, is just too difficult for normal people to engage in (or for hackers controlling other people's computers). The Bitcoin mining space is dominated by gigantic firms that run server farms, largely in China. Smaller or newer currencies like Zcash and Monero are thus more likely to pay off. In addition, Ivanov noted, Zcash and Monero promise more privacy for users and, as it happens, criminals, than Bitcoin and Ethereum.