I'd argue they make it less risky. Ransomeware has been around since the 90s, just not nearly as prevalent as it was harder to do without getting caught. They could easily instead demand somebody mail cash/money order to an abandoned address or mail forwarding service.
Not that "easily." Moving that much cash around requires a lot of manual effort and some skill at money laundering.
By removing that need, cryptocurrency makes ransomware scalable. And as Paul Graham and other Silicon Valley types have said a thousand times, scalability is the difference between a modest mom-and-pop operation and a rapidly growing enterprise.
You are correct in that handling that volume of physical cash is likely more difficult than I implied, though I don't think removal of cryptocurrency from the equation removes the ability to scale.
In my mind, the catalyzing effect of a cryptocurrency in this context is from:
1. The ability to move something of value digitally
2. The thing of value being resistant to governmental control--crypto can't be easily seized, but a US bank account can.
There may be other properties of crytocurrency that make it useful for ransomware, but I doubt there aren't other vehicles that could be used--though alternatives are likely less lucrative due to the overhead in laundering your ransomeware payment into hard currency.
It's a fascinating topic! Wikipedia has a pretty detailed entry on the topic and reports the earliest known ransomware attack to be as early as 1989[1][2]!
Interesting! I am a bit struck by how low the early ransoms seemed to be (looks like they were around $200 or less) even when they gained access to anonymous remote payment methods in ~2005 (e.g. eGold and Liberty Reserve).
It’s also interesting that all of those early anonymous remote payment methods have been significantly altered specifically to nerf their utility for extortion and scamming.
To be frank, it was the invention of bridges that enabled most of the crime. Bridges and round wheels. Humans lived happily in harmony with nature before that.