As the instances and threat of ransomware continues to wreak havoc on both businesses, governments and individuals around the world, it seems as though bitcoin has found itself closely intertwined with the malicious software.

As The Wall Street Journal pointed out on Friday (Aug. 19), cybercriminals have earned millions through ransomware schemes of encrypting computer systems and files, only to hold them hostage for ransom. Interestingly enough, bitcoin seems to be the currency of choice for many hackers when they are looking to collect untraceable funds from their victims.

Though ransomware isn’t a new threat, the availability of improved encryption software and the growing usage of bitcoin have contributed to a spike in the dangerous malware.

Data from the U.S. Department of Justice showed that in 2016 alone, the number of reported ransomware attacks have quadrupled since last year, reaching an average of 4,000 attacks per day.

These types of attacks could cost a business significantly when it comes to lost productivity and the labor it takes to recover and safeguard the captive data. According to research from the FBI released earlier this year, in the first three months of the year ransomware had already costs victims a total of nearly $209 million.

Cybercriminals are essentially making bank by extorting businesses and institutions to unlock computer servers, at a rate at which the FBI believes could result in ransomware soon becoming a $1 billion a year criminal industry this year. Shockingly, that number could end up being even higher after all of the related business costs are taken into consideration.

Researchers at U.K. corporate networking firm Citrix recently discovered that businesses are even shoring up reserves of bitcoin so they can pay ransoms as quickly as possible should they be hit with ransomware.

The company surveyed 250 IT and security professionals across U.K. businesses, and one-third said they were preemptively buying bitcoin in case of a ransomware attack, according to reports.

The survey also revealed other concerns regarding corporate cybersecurity measures. Nearly half of those questioned said their companies do not back up data at least once a day. Cybersecurity experts say data backups can be an effective deterrent against ransomware attacks.