The Password Life Cycle: User Behaviour in Managing Passwords.

Users need to keep track of many accounts and passwords. We conducted a series of interviews to investigate how users cope with these demanding tasks, and used Grounded Theory to analyze the interview results. We found that most users cope by reusing passwords and writing them down, but with a rich variety of behaviour and diverse personalized strategies. These approaches seem to disregard security advice, but at a detailed level they involve perceptive behaviour and careful self-management of user resources. We identify a password life cycle that follows users' password behaviour and how it develops over time as users adapt to changing circumstances and demands. Users' strategies have their limitations, but we suggest they indicate a rational response to the requirements of password authentication. We suggest that instead of simply advising against such behaviour, new approaches could be designed that harness existing user behaviour while limiting negative consequences.