Last April, while security researcher Patrick Wardle was attending the RSA security conference in San Francisco, a Taiwanese friend who lived in the city asked to meet for coffee, and for his help with what she described as a serious problem: China, she said, was hacking her iPhone. Wardle, a former NSA staffer and a prominent Apple-focused hacker who founded Digita Security, had heard that request from paranoid friends and acquaintances plenty of times before, making him naturally skeptical.