End-to-end encrypted messaging app Signal is secure for everyday use but shouldn't be used by government officials to have conversations regarding national security, cyber security experts say. It comes after US President Donald Trump's national security team accidentally included a journalist in a group chat, which was sharing information about plans for a military operation against the Iran-aligned Houthi rebel group. It's raised questions over the security of classified information shared by the Trump administration, and how safe it is to be sharing sensitive national security secrets on a platform such as Signal. What is Signal? Signal is a private...