A demand for 100 Bitcoins (approx. AUD$439,995) has been published in the dark web following a ransomware attack that devastated over 16,000 computers in 64 countries. In return for the payment, the hackers promise a private security key that could decrypt files that have been locked by the Petya/Goldeneye malware. 

https://www.news-mail.com.au/news/hackers-linked-ransomware-attack-issue-new-demand/3197266/