Your next car will be hacked. Will autonomous vehicles be worth it?

Self-driving cars could cut road deaths by 80%, but without better security they put us at risk of car hacking and even ransom demands, experts at SXSW say

You're about to drive to work. You turn on the ignition - and a message on the dash lights up. "We've hacked your car! Pay 10 bitcoin to get it back."

Hacking into software and then demanding a ransom to release it - what's known as ransomware - is not new. Finnish security expert Mikko Hypponen fully expects it to become a reality as self-driving or "autonomous" cars start to become more commonplace.