Malware
SunCrypt
According to PCrisk, Suncrypt ransomware prevents victims from accessing files by encryption.
SunCrypt is a Windows malware family.
Background
PCrisk explains that SunCrypt ransomware locks victims out of their files through encryption. It renames every encrypted file and drops a ransom note. The renaming works by attaching a string of random characters as the file's new extension.
Source: Malpedia (Fraunhofer FKIE).