Summer Camp For Hackers

What the world's hackers have been up to at their big annual meetings Black Hat and Def Con in Las Vegas. Plus the man behind Amazon's Alexa business Dave Limp talks to us about how the service might develop. And we witness a - thankfully fictional - hacking challenge that involves preventing a rogue state from firing nuclear missiles. Presented by Jane Wakefield, with BBC Online tech editor Leo Kelion, and special guest William Goodwin, Commissioning Editor at Computer Weekly.

(Image: Man with computer code reflected in dark glasses, Credit: Getty Images).