Efudex (Fluorouracil): Side Effects, Uses, Dosage ... - RxList
: While rare, some security researchers have noted that certain ransomware can "hijack" EFS to encrypt a user's files using Windows' own tools. If you see this window and haven't intentionally encrypted anything, it’s a good idea to run a malware scan.
: Normally, yes. It is a core part of Windows security.
The core technology that scrambles files to prevent unauthorized access. DRA (Data Recovery Agent)