There have been ways to store
encrypted files within Dropbox for quite some time.
Not exact matches
Ransomware often
encrypts user
files and threatens to delete the encryption key if a ransom is not paid
within some relatively short period of time, but other forms of ransomware involve a criminal actually stealing user data and threatening to publish it online if a ransom is not paid.
The attacker threatens that unless the ransom is paid, typically
within a couple of days, the
encrypted files will be forever lost and legal action may follow.
Risks (e.g. new allegations or defences added to pleadings, unexpected problems with degraded or
encrypted media or
files) that could threaten delivery of the project
within budget and schedule, and mitigation strategies