Rejoice Petya-infected victims!
The master key for the original version of the Petya ransomware has been released by its creator, allowing Petya-infected victims to recover their encrypted files without paying any ransom money.
But wait, Petya is not NotPetya.
Do not confuse Petya ransomware with the latest destructive NotPetya ransomware (also known as ExPetr and Eternal Petya) attacks
Source: Private Decryption Key For Original Petya Ransomware Released