Recently I was thinking if things like bitsocket, multisig setup, miniscript etc. can be used to make better ransomware. This post doesn’t encourage the use of ransomware to target people, however it is necessary to understand how things work and how can they evolve with time to prepare for solutions to prevent such attacks.
Any of those 4 setups can be used to make the app which encrypts/decrypts and communicate after being executed on victim's machine.
Triggering tasks based on Bitcoin events, communicate using Bitcoin transactions, using opentimestamps to store some data on Bitcoin blockchain can help to make better ransomware.
Ethereum smart contracts can also be used to make ransomware. I found two relevant medium articles and appreciate Jeffrey for the research.