But in fact, ransomware that targets the health-care sector is just returning to its roots. A research paper on ransomware from Palo Alto Networks, a cybersecurity company, shows that the first-ever ransomware attack went after AIDS researchers—and it was distributed on 5.25-inch floppy disks.

The year was 1989, and the AIDS epidemic was in full swing. The number of reported AIDS cases had hit 100,000 for the first time. An evolutionary biologist named Joseph Popp came up with a computer-based questionnaire he said would help determine patients’ risk of contracting AIDS, and he distributed 20,000 copies of it to researchers in 90 countries.

But the surveys on Popp’s floppy disks were a ruse. When participating scientists loaded the disk, their computers became infected with what would come to be known as a digital version of the AIDS virus. It lay dormant for a while: For the next 89 times the computer was turned on, everything would seem normal. But on the 90th boot, an angry red message splashed across the screen.

(Palo Alto Networks)

The virus scrambled the contents of the victims’ computers and offered to unlock them only in return for a “licensing fee.” It worked by encrypting filenames, a relatively primitive attack that still rendered most computers unusable.

Soon, security researchers produced antidotes that would recover the files locked away by the virus. The development of those tools, plus the difficulty of actually paying the ransom—it required sending a cashier’s check or an international money order to a P.O. Box in Panama—kept Popp from profiting much from his trick.

The biologist was soon arrested and charged with blackmail in the U.K. He claimed in court to have planned to donate the spoils of his caper to AIDS research, but The Guardian reported that his stunt was a reaction to being rejected for a job at the World Health Organization. He was eventually ruled mentally unfit to stand trial (the journalist Alina Simone found British reports citing his propensity for wearing condoms on his nose and curlers in his beard to protect from radiation) and was deported to the U.S., where he remained free until his death in 2007.

Now, nearly 30 years later, ransomware generally falls into two camps—and both draw on elements of Popp’s early virus.

The first type of modern ransomware, known as scareware, relies on computer users’ unfamiliarity with the inner workings of important software—and their profound fear of breaking their machines. Bandying about phrases like “SYSTEM WARNING” and “CRITICAL ERROR,” this type of malware tries to convince the user that something is horribly, terribly, wrong with their computer with insistent alerts and frightening splash screens, and then promises to sell just the tool to fix the problem for a bargain: a sum usually under 100 dollars. Once the unsuspecting user pays up, the alerts go away. (In one version, the scareware imitates the FBI, demanding a fine for the fictitious child pornography found on your laptop.)