... so-called dark web, according to the firm, which helps companies such as cryptocurrency exchanges investigate and prevent illegal transactions.
source https://www.google.com/url?rct=j&sa=t&url=https://www.bloomberg.com/news/articles/2019-07-01/bitcoin-criminals-set-to-spend-1-billion-on-dark-web-this-year&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNEagR_TESH6zdlPiWXmbxD6lV-lYQ
