SydneyMorningHerald: Former prime minister Malcolm Turnbull's handpicked cybersecurity tsar Alastair MacGibbon is quitting his role and has declared cyber attacks "the greatest existential threat we face". Mr MacGibbon has been the face of cybersecurity for federal authorities for the past three years, handling the public response to the cyberattack on the national census in 2016 and the hacking earlier this year of the Parliament and the major political parties...