Who Goes There?: Authentication Through the Lens of Privacy explores authenticationtechnologies (passwords, PKI, biometrics, etc.) and their implications for the privacyof the individuals being authenticated. As authentication becomes ever more ubiquitous, understanding its interplay with privacy is vital. The report examines numerousconcepts, including authentication, authorization, identification, privacy, and security. It provides a framework to guide thinking about these issues when deciding whetherand how to use authentication in a particular context. The book explains how privacyis affected by system design decisions. It also describes government’s unique rolein authentication and what this means for how government can use authenticationwith minimal invasions of privacy. In addition, Who Goes There? outlines usability andsecurity considerations and provides a primer on privacy law and policy.