From 2-spyware.com
Tisc ransomware is aiming to affect files as soon as it gets on the computer, so victims believe all the claims and pay the demanded sum. The virus belongs to a DJVU family of ransomware-type infections. This nasty malware will encrypt your files (video, photos documents) and makes them unopenable before marking files with an extension .tisc. All affected files on the machine or network receive the extension, so the user knows which pieces are encrypted.