A mid-year report from blockchain analytics firm Chainalysis published last year shows that thus far in 2021, addresses tied to ransomware attacks have hauled in as much as $81 million.

The firm stressed that the $81 million figure is “must be considered a floor for the time being, as the figure will almost certainly grow as we identify more ransomware addresses.” Per Chainlayis’s report, some $406 million in crypto payments were made to ransomware addresses in 2020, the highest figure on record.

Ransomware is malicious software that locks down a victim’s computer and files until they pay, typically in the form of cryptocurrency, for the system to then be unlocked. National headlines in the U.S. have honed in on ransomware in recent days because of the recent attack on Colonial Pipeline, a major energy transportation firm.

Colonial ultimately paid $5 million in bitcoin after its system was hit by ransomware, causing a shutdown of a pipeline system said to supply nearly half of the fuel on the East Coast U.S. Recent reports indicate that the group behind the attack, DarkSide, has since encountered problems of its own including the seizure of its servers. 

Data published last week by analysis firm Elliptic identified DarkSide’s bitcoin wallet, showing that the 75 BTC payment from Colonial was issued on May 8. That wallet also showed a $4.4 million payment made by Brenntag, a European chemical distributor, which was also affected by a DarkSide ransomware attack.