If you mine cryptocurrency such as bitcoin, you're making money. If you're also in the US (or are a US citizen abroad), Uncle Sam wants his cut.
source https://www.google.com/url?rct=j&sa=t&url=https://hendrixjoseph.github.io/example-schedule-c-for-cryptocurrency-mining/&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNFWXDOgqXqPBO_MRNAsNJUhSAhj7g
