From 2-spyware.com
AgeLocker ransomware is a cryptovirus[1] that encrypts data in the infected device. This ransomware[2] also is known as .sthd2 file virus because all infected files get .sthd2 extension. The infection encrypts all types of files, such as pictures, video, banking data, or backups.
AgeLocker virus is a little bit different than other ransomware because it is using the age encryption library/binary of the cryptographer Filippo Valsorda. The victims get a ransom note via email.