President Barack Obama has arrived in California to hold a summit on cybersecurity.<br /><br /> Fresh from the Sony hacking scandal and other hi-tech attacks, the US leader wants to encourage firms to share more data about cyber threats with the government and each other.<br /><br /> He is set to sign an executive order with that aim in mind. On Tuesday, the White House announced a new intelligence unit to coordinate analysis of cyberthreats.<br /><br /> But Silicon Valley giants are reluctant to fully support legislation requiring information sharing.<br /><br /> They want to see reforms to government surveillance practices exposed by former National Security Agency contractor Edward Snowden.<br /><br /> The recent attack on Sony Pictures has been described as “a game changer” by a senior White House official.<br /><br /> Hackers stole data, debilitated computers and pressured the studio to halt release of a satirical film about North Korean leader Kim Jong-un. The FBI took the unusual step of accusing Pyongyang of being responsible.<br /><br /> Friday
