The Author of Original Petya Ransomware – a person/group going by the name of Janus Cybercrime Solutions Published Master Decryption Key.
This key can decrypt all ransomware families part of the Petya family except NotPetya, which isn’t the work of Janus. This list includes:first petya ransomware version ,second petya version (mischa ransomware),third petya version (golden eye ransomware).
The author Janus released the master key on Wednesday in a tweet that linked to an encrypted and password-protected file uploaded on Mega.nz. But this key will only help those victims who cloned their drives and saved a copy of the encrypted data.
This key won’t help NotPetya victims because the NotPetya ransomware was created by “pirating” the original Petya ransomware and modifying its behavior by a process called patching. NotPetya used a different encryption routine and was proven to have no connection to the original Petya.