Great analysis of the trojan here: http://researchcenter.paloaltonetworks.com/2016/03/new-os-x-ransomware-keranger-infected-transmission-bittorrent-client-installer/
Business Insider article about this video: http://www.businessinsider.com/what-its-like-to-be-infected-with-keranger-ransomware-for-os-xmacs-2016-3
Cause somebody is gonna ask: http://j-walkispissed.bandcamp.com/album/assqu-ke
KeRanger is a file encrypting ransomware trojan hidden inside of a compromised copy of Transmission that runs on Mac OS X. As of the Sixth Day of March in the Year of our Lord two thousand and Sixteen there is not a free decryption tool for KeRanger encrypted files.