Tool : REvil / Sodinokibi Ransomware Decryptor
Use Type : Free To Use
Author : Bit Defender

REvil is a Ransomware-as-a-Service (RaaS) operator. It encrypts your files and asks for ransom money. Bit Defender in collaboration with a trusted law enforcement partner created a free universal decryptor for REvil/Sodinokib Ransomware. 

Note : Before using this tool, make backup of your all files. 

(Link sends you to official site)