We live in dangerous times. Government agencies charged with keeping us safe must have access to information to protect us from terrorists and other threats. But we do have and need Constitutional safeguards. If last year’s revelations about the National Security Agency’s collection of Americans’ phone and Internet data taught us anything, it’s that we need a national discussion on how our information is obtained. As we search for a balance between protecting privacy and maintaining security, we must understand exactly how private our information is.