Your digital security, any sufficiently paranoid person will remind you, is only as good as your physical security. The world's most sensitive users of technology, like dissidents, activists, or journalists in repressive regimes, have to fear not just hacking and online surveillance, but the reality that police, intelligence agents, or other intruders can simply break into your home, office, or hotel room.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.