Twitter’s former security chief has told US Congress there was “at least one agent” from China’s intelligence service on the social network’s payroll and that the company knowingly allowed India to add agents to the company roster as well, potentially giving those nations access to sensitive data about users. These were some of the troubling revelations from Peiter “Mudge” Zatko, a respected cybersecurity expert and Twitter whistleblower who appeared before the Senate Judiciary Committee to lay out his allegations against the company. Mr Zatko told legislators that the platform is plagued by weak cyber defences that make it vulnerable to…