SplinterJoke Ransomware encrypts user files and data and asks them to contact them for the decryption key. After encryption, it changes the wallpaper of the system saying that this ransomware is a Proof of Concept (POC) for SentinelOne.
It's strange that the SentinelOne antivirus engine detects the executable file as malicious. In addition, in the text note, the name of the company is spelt with an error - SetinelOne. Thus, it is unclear who did this, see below for real antivirus detections. It is closely related to DeathRansom Ransomware
SplinterJoke Ransomware Signatures
SplinterJoke Ransomware Download