The suspension of a Google engineer who claimed a computer chatbot he was working on had become sentient and was thinking and reasoning like a human being has put new scrutiny on the capacity of, and secrecy surrounding, the world of artificial intelligence (AI).

Two security researchers have identified five related techniques for hijacking internet accounts by preparing them to be commandeered in advance. And they claim that when they analyzed 75 popular internet services, almost half were vulnerable to at least one of these techniques.