Twitter is behind other Internet companies in providing the option of requiring a second form of authentication when accessing the service from an unidentified device. Such security usually involves typing in a one-time passcode sent to a mobile phone. Twitter recently had a full-time job posting for a software engineer with experience in designing and developing “user-facing security features” Last month, “extremely sophisticated” hackers breached the microblogging site’s servers and stole user names and encrypted/salted versions of passwords for 250,000 users.”]